Tweak changes.

* refs/remotes/tmux-openbsd/master:
  Draw bottom border with pane status line at the top.
  Bound the memory used by buffered control mode command replies (to 64 MB), GitHub issue 5565 from kagari dot shusei at proton dot me.
  Do not adjust prompt position on invalid Unicode, from Kaixuan Li.

.github/workflows/lock.yml

@@ -17,8 +17,9 @@ jobs:
   action:
     runs-on: ubuntu-latest
     if: github.repository == 'tmux/tmux'
+    timeout-minutes: 10
     steps:
-      - uses: dessant/lock-threads@v6
+      - uses: dessant/lock-threads@89ae32b08ed1a541efecbab17912962a5e38981c # v6
         with:
           github-token: ${{ github.token }}
           issue-inactive-days: '30'

.github/workflows/regress.yml

@@ -17,7 +17,7 @@ jobs:
     name: ${{ matrix.name }}
     runs-on: ${{ matrix.runner }}
     if: github.repository == 'tmux/tmux'
-    timeout-minutes: 45
+    timeout-minutes: 300
 
     strategy:
       fail-fast: false
@@ -38,7 +38,9 @@ jobs:
 
     steps:
       - name: checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
+        with:
+          persist-credentials: false
 
       - name: dependencies
         if: runner.os == 'Linux'
@@ -81,7 +83,7 @@ jobs:
 
       - name: logs
         if: failure()
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
         with:
           name: regress-logs-${{ matrix.name }}
           path: regress/logs/*.log

CHANGES

@@ -9,7 +9,12 @@ CHANGES FROM 3.7c TO 3.8
 
   - modal panes may be created with new-pane -O; a window can have one modal
     pane and it prevents interaction with the other panes while it is active.
-    A modal pane is now used for the editor in buffer mode;
+    -C closes the pane when the mouse is clicked outside it and -K sends all
+    keys, including the prefix key, to the pane. A modal pane is now used for
+    the editor in buffer mode;
+
+  - new-pane -A creates a floating pane which remains above a zoomed pane;
+    modal panes do this by default;
 
   - move-pane and resize-pane can now move and resize floating panes, including
     mouse dragging;
@@ -24,10 +29,15 @@ CHANGES FROM 3.7c TO 3.8
     -k for choose commands kills the pane when the mode exits, which is useful
     for modes in floating panes;
 
-  - pane-border-status has top-floating and bottom-floating, and there are new
-    default bindings under C-b g for common move and resize operations;
+  - command-prompt -P opens a prompt inside a pane rather than on the status
+    line;
 
-  - floating panes are unzoomed before creation to avoid a crash.
+  - pane-border-status has top-floating and bottom-floating, and there are new
+    default bindings under C-b g for common move and resize operations.
+
+* Layout strings now use a JSON subset format which includes floating panes.
+  The old format is still accepted; control mode clients receive old layouts
+  unless they set the new-layouts flag.
 
 * Add support for themes and improve default colours:
 
@@ -74,7 +84,7 @@ CHANGES FROM 3.7c TO 3.8
 
   - new hooks to cover areas including client create and destroy, pane
     activity, pane mode and prompt changes, pane movement and resizing, session
-    group changes and window creation, close and zoom;
+    group changes and window creation, close, swap and zoom;
 
   - OSC 133 escape sequences now trigger events: pane-command-started,
     pane-command-finished and pane-shell-prompt.
@@ -87,10 +97,23 @@ CHANGES FROM 3.7c TO 3.8
   while scrolling or while hovered and disappears after pane-scrollbars-timeout
   (Michael Grant).
 
-* Extend the fill-character option so both inside and outside the window can be
-  changed.
+* Add a clear-on-attach server option. When disabled, tmux does not enter the
+  alternate screen on attach and instead scrolls the existing terminal content
+  into the scrollback buffer so it remains accessible (issue 5508).
 
-* Change set-option and set-hooks to use formats and add a -F flag to each.
+* Copy mode can now automatically refresh as pane content changes with the
+  refresh-on, refresh-off and refresh-toggle commands. Automatic refresh is off
+  by default; refresh-now refreshes once and is bound to r. These replace
+  refresh-from-pane (issue 5165).
+
+* Extend the fill-character option so both inside and outside the window can be
+  changed, with a new default for unused areas inside the window.
+
+* Change show-options and show-hooks to use formats and add a -F flag to each.
+
+* Allow individual terminal features to be disabled by adding @ to their names
+  in terminal-features, and add a utf8 feature for terminals which support
+  UTF-8 output.
 
 * Add a #{A/count:frames} modifier to show a series of frames as an animation
   in the status line (issue 5412 from Fernando Daciuk).
@@ -105,6 +128,10 @@ CHANGES FROM 3.7c TO 3.8
 * Add new-window -E, respawn-pane -E and respawn-window -E as more convenient
   methods to create an empty pane (rather than using '' for the command).
 
+* Add capture-pane -I to include the time each line entered history.
+
+* Add a default C-b T binding to change the current pane title.
+
 * Menus now belong to the window, so appear on all clients.
 
 * Dragging over an existing copy mode selection now adjusts it (Michael Grant).
@@ -118,6 +145,13 @@ CHANGES FROM 3.7c TO 3.8
 * Copy mode no longer exits at the bottom while a selection is in progress
   (issue 5349).
 
+* Add copy-mode-current-line-style to set the style of the line containing the
+  cursor in copy mode (issue 5391).
+
+* Copy mode word commands now recognise all Unicode whitespace characters; a
+  space in word-separators matches any Unicode whitespace character (issue
+  5562).
+
 * Add style attributes for dimming colours (dim=) and for hyperlinks (link= and
   nolink) (issues 4842 and 4280 from Moritz Angermann).
 
@@ -128,7 +162,9 @@ CHANGES FROM 3.7c TO 3.8
 
 * Add or improve format variables including client_colours,
   pane_start_command_list, window_manual_width, window_manual_height,
-  pane_last_output_time, pane_modal_flag and window_modal_pane.
+  pane_last_output_time, pane_modal_flag, window_modal_pane, pane_private_modes,
+  pane_output_generation, history_added, history_collected, history_generation,
+  hook_fire_count and hook_fire_time.
 
 * Add additional pane sort orders, and a z sort order for choose-tree so
   floating panes can be sorted by z-index.
@@ -140,12 +176,18 @@ CHANGES FROM 3.7c TO 3.8
 
 * The mouse option now defaults to on.
 
+* The active-pane client flag has been removed.
+
 * Fix send-keys -K so keys are inserted in the correct place in the input
   queue, like keys from key bindings (issue 3476).
 
 * Fix control mode clients hanging on exit if pty data was still queued (Ben
   Maurer, issue 5356), and avoid sending notifications to clients which are
-  already exiting (Ben Maurer, issue 5357).
+  already exiting (Ben Maurer, issue 5357). Queue notifications so they are not
+  sent inside %begin/%end (issue 5458), do not let a stuck client prevent the
+  server from exiting (issue 5444), and reset control mode offsets when a pane
+  is respawned (issue 5498). Bound buffered command replies so a control mode
+  client that stops reading cannot consume unlimited memory (issue 5565).
 
 * Fix grouped sessions sometimes being left as unusable command targets while
   they are being killed (Bryce Miller, issue 5180).

Makefile.am

@@ -174,6 +174,7 @@ dist_tmux_SOURCES = \
 	input-keys.c \
 	input.c \
 	job.c \
+	json.c \
 	key-bindings.c \
 	key-string.c \
 	layout-custom.c \

arguments.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: arguments.c,v 1.66 2026/06/26 09:54:56 nicm Exp $ */
+/* $OpenBSD: arguments.c,v 1.67 2026/08/25 06:04:33 nicm Exp $ */
 
 /*
  * Copyright (c) 2010 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -762,8 +762,6 @@ args_make_commands_now(struct cmd *self, struct cmdq_item *item, u_int idx,
 		cmdq_error(item, "%s", error);
 		free(error);
 	}
-	else
-		cmdlist->references++;
 	args_make_commands_free(state);
 	return (cmdlist);
 }
@@ -827,8 +825,10 @@ args_make_commands(struct args_command_state *state, int argc, char **argv,
 	int			 i;
 
 	if (state->cmdlist != NULL) {
-		if (argc == 0)
+		if (argc == 0) {
+			state->cmdlist->references++;
 			return (state->cmdlist);
+		}
 		return (cmd_list_copy(state->cmdlist, argc, argv));
 	}
 

client.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: client.c,v 1.167 2026/08/17 07:56:56 nicm Exp $ */
+/* $OpenBSD: client.c,v 1.168 2026/08/17 20:14:31 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -712,6 +712,9 @@ client_dispatch_wait(struct imsg *imsg)
 		fprintf(stderr, "server version is too old for client\n");
 		proc_exit(client_proc);
 		break;
+	default:
+		log_debug("unknown message type %u", imsg->hdr.type);
+		break;
 	}
 }
 
@@ -798,5 +801,8 @@ client_dispatch_attached(struct imsg *imsg)
 		system(data);
 		proc_send(client_peer, MSG_UNLOCK, -1, NULL, 0);
 		break;
+	default:
+		log_debug("unknown message type %u", imsg->hdr.type);
+		break;
 	}
 }

cmd-capture-pane.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-capture-pane.c,v 1.68 2026/07/20 11:16:33 nicm Exp $ */
+/* $OpenBSD: cmd-capture-pane.c,v 1.69 2026/09/08 07:31:59 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Jonathan Alvarado <radobobo@users.sourceforge.net>
@@ -42,8 +42,8 @@ const struct cmd_entry cmd_capture_pane_entry = {
 	.name = "capture-pane",
 	.alias = "capturep",
 
-	.args = { "ab:CeE:FHJLMNpPqRS:Tt:", 0, 0, NULL },
-	.usage = "[-aCeFHJLMNpPqRT] " CMD_BUFFER_USAGE " [-E end-line] "
+	.args = { "ab:CeE:FHIJLMNpPqRS:Tt:", 0, 0, NULL },
+	.usage = "[-aCeFHIJLMNpPqRT] " CMD_BUFFER_USAGE " [-E end-line] "
 		 "[-S start-line] " CMD_TARGET_PANE_USAGE,
 
 	.target = { 't', CMD_FIND_PANE, 0 },
@@ -200,7 +200,7 @@ cmd_capture_pane_pending(struct args *args, struct window_pane *wp,
 				tmp[0] = line[i];
 				tmp[1] = '\0';
 			} else
-				xsnprintf(tmp, sizeof tmp, "\\%03hho", line[i]);
+				snprintf(tmp, sizeof tmp, "\\%03hho", line[i]);
 			buf = cmd_capture_pane_append(buf, len, tmp,
 			    strlen(tmp));
 		}
@@ -259,7 +259,7 @@ cmd_capture_pane_history(struct args *args, struct cmdq_item *item,
 	struct grid_cell		*gc = NULL;
 	struct window_mode_entry	*wme;
 	int				 n, join_lines, number_lines, flags = 0;
-	int				 show_flags, hyperlinks;
+	int				 show_flags, show_time, hyperlinks;
 	u_int				*links = NULL, nlinks = 0;
 	u_int				 i, sx, top, bottom, tmp;
 	char				*cause, *buf = NULL, *line, b[64], *cp;
@@ -342,6 +342,7 @@ cmd_capture_pane_history(struct args *args, struct cmdq_item *item,
 		flags |= GRID_STRING_TRIM_SPACES;
 	number_lines = args_has(args, 'L');
 	show_flags = args_has(args, 'F');
+	show_time = args_has(args, 'I');
 	hyperlinks = args_has(args, 'H');
 	if (hyperlinks)
 		links = xreallocarray(NULL, gd->sx, sizeof *links);
@@ -358,6 +359,7 @@ cmd_capture_pane_history(struct args *args, struct cmdq_item *item,
 			free(line);
 			continue;
 		}
+		gl = grid_peek_line(gd, i);
 
 		if (number_lines) {
 			if (i >= gd->hsize)
@@ -368,11 +370,16 @@ cmd_capture_pane_history(struct args *args, struct cmdq_item *item,
 			if (n >= 0)
 				buf = cmd_capture_pane_append(buf, len, b, n);
 		}
+		if (show_time) {
+			n = snprintf(b, sizeof b, "%llu ",
+			    (unsigned long long)grid_line_time(gl));
+			if (n >= 0)
+				buf = cmd_capture_pane_append(buf, len, b, n);
+		}
 		if (show_flags) {
 			cp = b;
 			*cp = '\0';
 
-			gl = grid_peek_line(gd, i);
 			if (gl->flags & GRID_LINE_DEAD)
 				*cp++ = 'D';
 			if (gl->flags & GRID_LINE_HYPERLINK)
@@ -393,7 +400,6 @@ cmd_capture_pane_history(struct args *args, struct cmdq_item *item,
 		}
 		buf = cmd_capture_pane_append(buf, len, line, linelen);
 
-		gl = grid_peek_line(gd, i);
 		if (!join_lines || !(gl->flags & GRID_LINE_WRAPPED))
 			buf[(*len)++] = '\n';
 

cmd-command-prompt.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-command-prompt.c,v 1.75 2026/06/25 11:39:11 nicm Exp $ */
+/* $OpenBSD: cmd-command-prompt.c,v 1.76 2026/08/25 06:04:33 nicm Exp $ */
 
 /*
  * Copyright (c) 2008 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -242,9 +242,11 @@ cmd_command_prompt_callback(struct client *c, void *data, const char *s,
 	} else if (item == NULL) {
 		new_item = cmdq_get_command(cmdlist, NULL);
 		cmdq_append(c, new_item);
+		cmd_list_free(cmdlist);
 	} else {
 		new_item = cmdq_get_command(cmdlist, cmdq_get_state(item));
 		cmdq_insert_after(item, new_item);
+		cmd_list_free(cmdlist);
 	}
 	cmd_free_argv(argc, argv);
 

cmd-display-menu.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-display-menu.c,v 1.52 2026/07/14 19:07:03 nicm Exp $ */
+/* $OpenBSD: cmd-display-menu.c,v 1.53 2026/08/31 07:46:55 nicm Exp $ */
 
 /*
  * Copyright (c) 2019 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -591,6 +591,8 @@ cmd_display_popup_exec(struct cmd *self, struct cmdq_item *item)
 		server_client_clear_overlay(tc);
 		return (CMD_RETURN_NORMAL);
 	}
+	if (tc->flags & CLIENT_CONTROL)
+		return (CMD_RETURN_NORMAL);
 	if (!modify && tc->overlay_draw != NULL)
 		return (CMD_RETURN_NORMAL);
 

cmd-display-message.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-display-message.c,v 1.65 2026/02/23 08:46:57 nicm Exp $ */
+/* $OpenBSD: cmd-display-message.c,v 1.66 2026/09/08 08:33:10 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Tiago Cunha <me@tiagocunha.org>
@@ -39,8 +39,8 @@ const struct cmd_entry cmd_display_message_entry = {
 	.name = "display-message",
 	.alias = "display",
 
-	.args = { "aCc:d:lINpt:F:v", 0, 1, NULL },
-	.usage = "[-aCIlNpv] [-c target-client] [-d delay] [-F format] "
+	.args = { "aCc:d:jlINpt:F:v", 0, 1, NULL },
+	.usage = "[-aCIjlNpv] [-c target-client] [-d delay] [-F format] "
 		 CMD_TARGET_PANE_USAGE " [message]",
 
 	.target = { 't', CMD_FIND_PANE, CMD_FIND_CANFAIL },
@@ -67,14 +67,15 @@ cmd_display_message_exec(struct cmd *self, struct cmdq_item *item)
 	struct winlink		*wl = target->wl;
 	struct window_pane	*wp = target->wp;
 	const char		*template;
-	char			*msg, *cause;
+	char			*msg, *cause = NULL;
 	int			 delay = -1, flags, Nflag = args_has(args, 'N');
 	int			 Cflag = args_has(args, 'C');
 	struct format_tree	*ft;
 	u_int			 count = args_count(args);
 	struct evbuffer		*evb;
+	struct json_node	*jn;
 
-	if (args_has(args, 'I')) {
+	if (args_has(args, 'I') && !args_has(args, 'j')) {
 		if (wp == NULL)
 			return (CMD_RETURN_NORMAL);
 		switch (window_pane_start_input(wp, item, &cause)) {
@@ -107,7 +108,9 @@ cmd_display_message_exec(struct cmd *self, struct cmdq_item *item)
 		template = args_string(args, 0);
 	else
 		template = args_get(args, 'F');
-	if (template == NULL)
+	if (args_has(args, 'j') && template == NULL)
+		template = "";
+	else if (template == NULL)
 		template = DISPLAY_MESSAGE_TEMPLATE;
 
 	/*
@@ -129,7 +132,7 @@ cmd_display_message_exec(struct cmd *self, struct cmdq_item *item)
 	ft = format_create(cmdq_get_client(item), item, FORMAT_NONE, flags);
 	format_defaults(ft, c, s, wl, wp);
 
-	if (args_has(args, 'a')) {
+	if (args_has(args, 'a') && !args_has(args, 'j')) {
 		format_each(ft, cmd_display_message_each, item);
 		format_free(ft);
 		return (CMD_RETURN_NORMAL);
@@ -139,6 +142,19 @@ cmd_display_message_exec(struct cmd *self, struct cmdq_item *item)
 		msg = xstrdup(template);
 	else
 		msg = format_expand_time(ft, template);
+	if (args_has(args, 'j')) {
+		jn = json_parse(msg, &cause);
+		if (jn == NULL) {
+			cmdq_error(item, "%s", cause);
+			free(cause);
+			free(msg);
+			format_free(ft);
+			return (CMD_RETURN_ERROR);
+		}
+		free(msg);
+		msg = json_to_string(jn);
+		json_destroy_node(jn);
+	}
 
 	if (cmdq_get_client(item) == NULL)
 		cmdq_error(item, "%s", msg);

cmd-find.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-find.c,v 1.87 2026/07/17 12:42:51 nicm Exp $ */
+/* $OpenBSD: cmd-find.c,v 1.88 2026/09/07 12:05:12 nicm Exp $ */
 
 /*
  * Copyright (c) 2015 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -388,9 +388,11 @@ cmd_find_get_window_with_session(struct cmd_find_state *fs, const char *window)
 
 	/* Try as an offset. */
 	if (!exact && (window[0] == '+' || window[0] == '-')) {
-		if (window[1] != '\0')
-			n = strtonum(window + 1, 1, INT_MAX, NULL);
-		else
+		if (window[1] != '\0') {
+			n = strtonum(window + 1, 1, INT_MAX, &errstr);
+			if (errstr != NULL)
+				return (-1);
+		} else
 			n = 1;
 		s = fs->s;
 		if (fs->flags & CMD_FIND_WINDOW_INDEX) {
@@ -626,9 +628,11 @@ cmd_find_get_pane_with_window(struct cmd_find_state *fs, const char *pane)
 
 	/* Try as an offset. */
 	if (pane[0] == '+' || pane[0] == '-') {
-		if (pane[1] != '\0')
-			n = strtonum(pane + 1, 1, INT_MAX, NULL);
-		else
+		if (pane[1] != '\0') {
+			n = strtonum(pane + 1, 1, INT_MAX, &errstr);
+			if (errstr != NULL)
+				return (-1);
+		} else
 			n = 1;
 		wp = fs->w->active;
 		if (pane[0] == '+')

cmd-if-shell.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-if-shell.c,v 1.86 2025/08/01 09:05:51 nicm Exp $ */
+/* $OpenBSD: cmd-if-shell.c,v 1.87 2026/08/25 06:04:33 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Tiago Cunha <me@tiagocunha.org>
@@ -98,6 +98,7 @@ cmd_if_shell_exec(struct cmd *self, struct cmdq_item *item)
 			return (CMD_RETURN_ERROR);
 		new_item = cmdq_get_command(cmdlist, cmdq_get_state(item));
 		cmdq_insert_after(item, new_item);
+		cmd_list_free(cmdlist);
 		return (CMD_RETURN_NORMAL);
 	}
 
@@ -164,9 +165,11 @@ cmd_if_shell_callback(struct job *job)
 	} else if (item == NULL) {
 		new_item = cmdq_get_command(cmdlist, NULL);
 		cmdq_append(c, new_item);
+		cmd_list_free(cmdlist);
 	} else {
 		new_item = cmdq_get_command(cmdlist, cmdq_get_state(item));
 		cmdq_insert_after(item, new_item);
+		cmd_list_free(cmdlist);
 	}
 
 out:

cmd-list-panes.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-list-panes.c,v 1.40 2026/06/01 14:01:09 nicm Exp $ */
+/* $OpenBSD: cmd-list-panes.c,v 1.41 2026/09/08 10:20:08 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -97,6 +97,7 @@ cmd_list_panes_window(struct cmd *self, struct session *s, struct winlink *wl,
     struct cmdq_item *item, int type)
 {
 	struct args		*args = cmd_get_args(self);
+	struct client		*c = cmdq_get_client(item);
 	struct window_pane	*wp, **l;
 	u_int			 i, n;
 	struct format_tree	*ft;
@@ -147,7 +148,7 @@ cmd_list_panes_window(struct cmd *self, struct session *s, struct winlink *wl,
 		wp = l[i];
 		ft = format_create(cmdq_get_client(item), item, FORMAT_NONE, 0);
 		format_add(ft, "line", "%u", n);
-		format_defaults(ft, NULL, s, wl, wp);
+		format_defaults(ft, c, s, wl, wp);
 
 		if (filter != NULL) {
 			expanded = format_expand(ft, filter);

cmd-list-sessions.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-list-sessions.c,v 1.36 2026/02/27 08:25:12 nicm Exp $ */
+/* $OpenBSD: cmd-list-sessions.c,v 1.37 2026/09/08 10:20:08 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -53,6 +53,7 @@ static enum cmd_retval
 cmd_list_sessions_exec(struct cmd *self, struct cmdq_item *item)
 {
 	struct args		 *args = cmd_get_args(self);
+	struct client		 *c = cmdq_get_client(item);
 	struct session		**l;
 	u_int		 	  n, i;
 	struct format_tree	 *ft;
@@ -76,7 +77,7 @@ cmd_list_sessions_exec(struct cmd *self, struct cmdq_item *item)
 	for (i = 0; i < n; i++) {
 		ft = format_create(cmdq_get_client(item), item, FORMAT_NONE, 0);
 		format_add(ft, "line", "%u", i);
-		format_defaults(ft, NULL, l[i], NULL, NULL);
+		format_defaults(ft, c, l[i], NULL, NULL);
 
 		if (filter != NULL) {
 			expanded = format_expand(ft, filter);

cmd-list-windows.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-list-windows.c,v 1.50 2026/02/27 08:25:12 nicm Exp $ */
+/* $OpenBSD: cmd-list-windows.c,v 1.51 2026/09/08 10:20:08 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -60,6 +60,7 @@ cmd_list_windows_exec(struct cmd *self, struct cmdq_item *item)
 {
 	struct args		*args = cmd_get_args(self);
 	struct cmd_find_state	*target = cmdq_get_target(item);
+	struct client		*c = cmdq_get_client(item);
 	struct winlink		*wl, **l;
 	struct session		*s;
 	u_int			 i, n;
@@ -94,7 +95,7 @@ cmd_list_windows_exec(struct cmd *self, struct cmdq_item *item)
 		s = wl->session;
 		ft = format_create(cmdq_get_client(item), item, FORMAT_NONE, 0);
 		format_add(ft, "line", "%u", n);
-		format_defaults(ft, NULL, s, wl, NULL);
+		format_defaults(ft, c, s, wl, NULL);
 
 		if (filter != NULL) {
 			expanded = format_expand(ft, filter);

cmd-new-window.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-new-window.c,v 1.103 2026/07/08 08:07:42 nicm Exp $ */
+/* $OpenBSD: cmd-new-window.c,v 1.104 2026/09/03 21:04:11 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -60,7 +60,8 @@ cmd_new_window_exec(struct cmd *self, struct cmdq_item *item)
 	struct client		*tc = cmdq_get_target_client(item);
 	struct session		*s = target->s;
 	struct winlink		*wl = target->wl, *new_wl = NULL;
-	int			 idx = target->idx, before, count = args_count(args);
+	int			 idx = target->idx, before;
+	int			 count = args_count(args);
 	char			*cause = NULL, *cp, *expanded, *wname = NULL;
 	const char		*template, *name;
 	struct cmd_find_state	 fs;
@@ -74,8 +75,10 @@ cmd_new_window_exec(struct cmd *self, struct cmdq_item *item)
 	}
 
 	/*
-	 * If -S and -n are given and -t is not and a single window with this
-	 * name already exists, select it.
+	 * If -S is given, select an existing window instead of creating a
+	 * new one: preferring -t if it already points at a window, or
+	 * otherwise -n if one exists with that name. If neither matches,
+	 * fall through and create a window as normal.
 	 */
 	name = args_get(args, 'n');
 	if (name != NULL) {
@@ -88,32 +91,39 @@ cmd_new_window_exec(struct cmd *self, struct cmdq_item *item)
 		wname = clean_name(expanded, 0);
 		free(expanded);
 	}
-	if (args_has(args, 'S') && wname != NULL && target->idx == -1) {
-		expanded = format_single(item, wname, c, s, NULL, NULL);
-		RB_FOREACH(wl, winlinks, &s->windows) {
-			if (strcmp(wl->window->name, expanded) != 0)
-				continue;
-			if (new_wl == NULL) {
-				new_wl = wl;
-				continue;
+	if (args_has(args, 'S')) {
+		if (idx != -1)
+			new_wl = winlink_find_by_index(&s->windows, idx);
+		else if (wname != NULL) {
+			expanded = format_single(item, wname, c, s, NULL, NULL);
+			RB_FOREACH(wl, winlinks, &s->windows) {
+				if (strcmp(wl->window->name, expanded) != 0)
+					continue;
+				if (new_wl == NULL) {
+					new_wl = wl;
+					continue;
+				}
+				cmdq_error(item, "multiple windows named %s",
+				    wname);
+				free(wname);
+				free(expanded);
+				return (CMD_RETURN_ERROR);
 			}
-			cmdq_error(item, "multiple windows named %s", wname);
-			free(wname);
 			free(expanded);
-			return (CMD_RETURN_ERROR);
 		}
-		free(expanded);
-		if (new_wl != NULL) {
-			free(wname);
-			if (args_has(args, 'd'))
-				return (CMD_RETURN_NORMAL);
-			if (session_set_current(s, new_wl) == 0)
-				server_redraw_session(s);
-			if (c != NULL && c->session != NULL)
-				s->curw->window->latest = c;
-			recalculate_sizes();
+	}
+
+	/* Found an existing window to select instead of creating a new one. */
+	if (new_wl != NULL) {
+		free(wname);
+		if (args_has(args, 'd'))
 			return (CMD_RETURN_NORMAL);
-		}
+		if (session_set_current(s, new_wl) == 0)
+			server_redraw_session(s);
+		if (c != NULL && c->session != NULL)
+			s->curw->window->latest = c;
+		recalculate_sizes();
+		return (CMD_RETURN_NORMAL);
 	}
 
 	before = args_has(args, 'b');

cmd-parse.y

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-parse.y,v 1.58 2026/04/27 12:31:11 nicm Exp $ */
+/* $OpenBSD: cmd-parse.y,v 1.60 2026/09/08 10:20:08 nicm Exp $ */
 
 /*
  * Copyright (c) 2019 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -210,7 +210,7 @@ expanded	: format
 				cmd_find_from_client(&fs, c, 0);
 				fsp = &fs;
 			}
-			ft = format_create(NULL, pi->item, FORMAT_NONE, flags);
+			ft = format_create(c, pi->item, FORMAT_NONE, flags);
 			format_defaults(ft, c, fsp->s, fsp->wl, fsp->wp);
 
 			$$ = format_expand(ft, $1);
@@ -802,6 +802,7 @@ cmd_parse_expand_alias(struct cmd_parse_command *cmd,
 	if (last == NULL) {
 		pr->status = CMD_PARSE_SUCCESS;
 		pr->cmdlist = cmd_list_new();
+		cmd_parse_free_commands(cmds);
 		return (1);
 	}
 
@@ -814,6 +815,7 @@ cmd_parse_expand_alias(struct cmd_parse_command *cmd,
 	pi->flags |= CMD_PARSE_NOALIAS;
 	cmd_parse_build_commands(cmds, pi, pr);
 	pi->flags &= ~CMD_PARSE_NOALIAS;
+	cmd_parse_free_commands(cmds);
 	return (1);
 }
 

cmd-queue.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-queue.c,v 1.122 2026/08/03 13:38:42 nicm Exp $ */
+/* $OpenBSD: cmd-queue.c,v 1.123 2026/08/24 20:34:26 nicm Exp $ */
 
 /*
  * Copyright (c) 2013 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -850,7 +850,18 @@ cmdq_error(struct cmdq_item *item, const char *fmt, ...)
 
 	if (c == NULL) {
 		cmd_get_source(cmd, &file, &line);
-		cfg_add_cause("%s:%u: %s", file, line, msg);
+		if (!cfg_finished) {
+			if (file != NULL)
+				cfg_add_cause("%s:%u: %s", file, line, msg);
+			else
+				cfg_add_cause("%s", msg);
+		} else {
+			if (file != NULL) {
+				server_add_message("message: %s:%u: %s", file,
+				    line, msg);
+			} else
+				server_add_message("message: %s", msg);
+		}
 	} else if (c->session == NULL || (c->flags & CLIENT_CONTROL)) {
 		server_add_message("%s message: %s", c->name, msg);
 		if (~c->flags & CLIENT_UTF8) {

cmd-resize-pane.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-resize-pane.c,v 1.67 2026/07/10 13:38:45 nicm Exp $ */
+/* $OpenBSD: cmd-resize-pane.c,v 1.68 2026/08/31 07:44:39 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -92,6 +92,7 @@ cmd_resize_pane_exec(struct cmd *self, struct cmdq_item *item)
 		return (CMD_RETURN_NORMAL);
 	}
 	server_unzoom_window(w);
+	lc = wp->layout_cell; /* may have been replaced by unzoom */
 
 	if (args_has(args, 'x')) {
 		x = args_percentage(args, 'x', 0, PANE_MAXIMUM, w->sx, &cause);

cmd-run-shell.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-run-shell.c,v 1.93 2026/07/17 12:42:51 nicm Exp $ */
+/* $OpenBSD: cmd-run-shell.c,v 1.94 2026/08/25 06:04:33 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Tiago Cunha <me@tiagocunha.org>
@@ -233,9 +233,11 @@ cmd_run_shell_timer(__unused int fd, __unused short events, void* arg)
 	} else if (item == NULL) {
 		new_item = cmdq_get_command(cmdlist, NULL);
 		cmdq_append(c, new_item);
+		cmd_list_free(cmdlist);
 	} else {
 		new_item = cmdq_get_command(cmdlist, cmdq_get_state(item));
 		cmdq_insert_after(item, new_item);
+		cmd_list_free(cmdlist);
 	}
 
 	if (cdata->item != NULL)

cmd-select-layout.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-select-layout.c,v 1.43 2026/07/10 13:38:45 nicm Exp $ */
+/* $OpenBSD: cmd-select-layout.c,v 1.45 2026/09/09 07:03:39 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -73,12 +73,13 @@ cmd_select_layout_exec(struct cmd *self, struct cmdq_item *item)
 {
 	struct args		*args = cmd_get_args(self);
 	struct cmd_find_state	*target = cmdq_get_target(item);
+	struct client		*c = cmdq_get_target_client(item);
 	struct winlink		*wl = target->wl;
 	struct window		*w = wl->window;
 	struct window_pane	*wp = target->wp;
 	const char		*layoutname;
-	char			*oldlayout, *cause;
-	int			 next, previous, layout;
+	char			*oldlayout, *cause = NULL;
+	int			 next, previous, layout, flags = 0;
 
 	server_unzoom_window(w);
 
@@ -89,8 +90,12 @@ cmd_select_layout_exec(struct cmd *self, struct cmdq_item *item)
 	if (args_has(args, 'p'))
 		previous = 1;
 
+	if (c != NULL &&
+	    (c->flags & CLIENT_CONTROL) &&
+	    (~c->flags & CLIENT_CONTROL_NEWLAYOUTS))
+		flags |= LAYOUT_CUSTOM_OLD_FORMAT;
 	oldlayout = w->old_layout;
-	w->old_layout = layout_dump(w, w->layout_root);
+	w->old_layout = layout_dump(w, w->layout_root, flags);
 
 	if (next || previous) {
 		if (next)

cmd-select-pane.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-select-pane.c,v 1.77 2026/07/17 12:42:51 nicm Exp $ */
+/* $OpenBSD: cmd-select-pane.c,v 1.78 2026/08/20 09:19:24 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -160,6 +160,7 @@ cmd_select_pane_exec(struct cmd *self, struct cmdq_item *item)
 	char			*title;
 	const char		*style;
 	struct options_entry	*o;
+	int			 visible, Zflag = args_has(args, 'Z');
 
 	if (entry == &cmd_last_pane_entry || args_has(args, 'l')) {
 		/*
@@ -185,14 +186,18 @@ cmd_select_pane_exec(struct cmd *self, struct cmdq_item *item)
 			server_redraw_window_borders(lastwp->window);
 			server_status_window(lastwp->window);
 		} else {
-			if (window_push_zoom(w, 0, args_has(args, 'Z')))
+			if (w->modal != NULL && lastwp != w->modal)
+				visible = 1;
+			else
+				visible = window_pane_is_visible(lastwp);
+			if (!visible && window_push_zoom(w, 0, Zflag))
 				server_redraw_window(w);
 			window_redraw_active_switch(w, lastwp);
 			if (window_set_active_pane(w, lastwp, 1)) {
 				cmd_find_from_winlink(current, wl, 0);
 				cmd_select_pane_redraw(w);
 			}
-			if (window_pop_zoom(w))
+			if (!visible && window_pop_zoom(w))
 				server_redraw_window(w);
 		}
 		return (CMD_RETURN_NORMAL);
@@ -268,14 +273,18 @@ cmd_select_pane_exec(struct cmd *self, struct cmdq_item *item)
 
 	if (wp == w->active)
 		return (CMD_RETURN_NORMAL);
-	if (window_push_zoom(w, 0, args_has(args, 'Z')))
+	if (w->modal != NULL && wp != w->modal)
+		visible = 1;
+	else
+		visible = window_pane_is_visible(wp);
+	if (!visible && window_push_zoom(w, 0, Zflag))
 		server_redraw_window(w);
 	window_redraw_active_switch(w, wp);
 	if (window_set_active_pane(w, wp, 1))
 		cmd_find_from_winlink_pane(current, wl, wp, 0);
 	cmdq_insert_hook(s, item, current, "after-select-pane");
 	cmd_select_pane_redraw(w);
-	if (window_pop_zoom(w))
+	if (!visible && window_pop_zoom(w))
 		server_redraw_window(w);
 
 	return (CMD_RETURN_NORMAL);

cmd-set-buffer.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-set-buffer.c,v 1.37 2026/02/15 17:43:26 nicm Exp $ */
+/* $OpenBSD: cmd-set-buffer.c,v 1.38 2026/08/24 07:05:23 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -100,6 +100,7 @@ cmd_set_buffer_exec(struct cmd *self, struct cmdq_item *item)
 			cmdq_error(item, "%s", cause);
 			goto fail;
 		}
+		free(bufname);
 		return (CMD_RETURN_NORMAL);
 	}
 
@@ -107,8 +108,10 @@ cmd_set_buffer_exec(struct cmd *self, struct cmdq_item *item)
 		cmdq_error(item, "no data specified");
 		goto fail;
 	}
-	if ((newsize = strlen(args_string(args, 0))) == 0)
+	if ((newsize = strlen(args_string(args, 0))) == 0) {
+		free(bufname);
 		return (CMD_RETURN_NORMAL);
+	}
 
 	if (args_has(args, 'a') && pb != NULL) {
 		olddata = paste_buffer_data(pb, &bufsize);
@@ -127,6 +130,7 @@ cmd_set_buffer_exec(struct cmd *self, struct cmdq_item *item)
 	if (args_has(args, 'w') && tc != NULL)
  		tty_set_selection(&tc->tty, "", bufdata, bufsize);
 
+	free(bufname);
 	return (CMD_RETURN_NORMAL);
 
 fail:

cmd-source-file.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-source-file.c,v 1.62 2025/11/18 08:42:09 nicm Exp $ */
+/* $OpenBSD: cmd-source-file.c,v 1.63 2026/08/18 08:05:05 nicm Exp $ */
 
 /*
  * Copyright (c) 2008 Tiago Cunha <me@tiagocunha.org>
@@ -50,6 +50,7 @@ const struct cmd_entry cmd_source_file_entry = {
 
 struct cmd_source_file_data {
 	struct cmdq_item	 *item;
+	struct client		 *client;
 	int			  flags;
 
 	struct cmdq_item	 *after;
@@ -60,10 +61,24 @@ struct cmd_source_file_data {
 	u_int			  nfiles;
 };
 
-static enum cmd_retval
-cmd_source_file_complete_cb(struct cmdq_item *item, __unused void *data)
+static void
+cmd_source_file_free_data(struct cmd_source_file_data *cdata)
 {
-	struct client	*c = cmdq_get_client(item);
+	u_int	i;
+
+	for (i = 0; i < cdata->nfiles; i++)
+		free(cdata->files[i]);
+	free(cdata->files);
+	if (cdata->client != NULL)
+		server_client_unref(cdata->client);
+	free(cdata);
+}
+
+static enum cmd_retval
+cmd_source_file_complete_cb(struct cmdq_item *item, void *data)
+{
+	struct cmd_source_file_data	*cdata = data;
+	struct client			*c = cdata->client;
 
 	if (c == NULL) {
 		cmd_source_file_depth--;
@@ -74,36 +89,36 @@ cmd_source_file_complete_cb(struct cmdq_item *item, __unused void *data)
 	}
 
 	cfg_print_causes(item);
+	cmd_source_file_free_data(cdata);
 	return (CMD_RETURN_NORMAL);
 }
 
 static void
-cmd_source_file_complete(struct client *c, struct cmd_source_file_data *cdata)
+cmd_source_file_complete(struct cmd_source_file_data *cdata)
 {
+	struct client		*c = cdata->client;
 	struct cmdq_item	*new_item;
-	u_int			 i;
 
-	if (cfg_finished) {
-		if (cdata->retval == CMD_RETURN_ERROR &&
-		    c != NULL &&
-		    c->session == NULL)
-			c->retval = 1;
-		new_item = cmdq_get_callback(cmd_source_file_complete_cb, NULL);
-		cmdq_insert_after(cdata->after, new_item);
+	if (!cfg_finished) {
+		cmd_source_file_free_data(cdata);
+		return;
 	}
 
-	for (i = 0; i < cdata->nfiles; i++)
-		free(cdata->files[i]);
-	free(cdata->files);
-	free(cdata);
+	if (cdata->retval == CMD_RETURN_ERROR &&
+	    c != NULL &&
+	    c->session == NULL)
+		c->retval = 1;
+	new_item = cmdq_get_callback(cmd_source_file_complete_cb, cdata);
+	cmdq_insert_after(cdata->after, new_item);
 }
 
 static void
-cmd_source_file_done(struct client *c, const char *path, int error,
-    int closed, struct evbuffer *buffer, void *data)
+cmd_source_file_done(__unused struct client *oc, const char *path,
+    int error, int closed, struct evbuffer *buffer, void *data)
 {
 	struct cmd_source_file_data	*cdata = data;
 	struct cmdq_item		*item = cdata->item;
+	struct client			*c = cdata->client;
 	void				*bdata = EVBUFFER_DATA(buffer);
 	size_t				 bsize = EVBUFFER_LENGTH(buffer);
 	u_int				 n;
@@ -127,7 +142,7 @@ cmd_source_file_done(struct client *c, const char *path, int error,
 	if (n < cdata->nfiles)
 		file_read(c, cdata->files[n], cmd_source_file_done, cdata);
 	else {
-		cmd_source_file_complete(c, cdata);
+		cmd_source_file_complete(cdata);
 		cmdq_continue(item);
 	}
 }
@@ -187,6 +202,9 @@ cmd_source_file_exec(struct cmd *self, struct cmdq_item *item)
 
 	cdata = xcalloc(1, sizeof *cdata);
 	cdata->item = item;
+	cdata->client = c;
+	if (c != NULL)
+		c->references++;
 
 	if (args_has(args, 'q'))
 		cdata->flags |= CMD_PARSE_QUIET;
@@ -249,7 +267,7 @@ cmd_source_file_exec(struct cmd *self, struct cmdq_item *item)
 		file_read(c, cdata->files[0], cmd_source_file_done, cdata);
 		retval = CMD_RETURN_WAIT;
 	} else
-		cmd_source_file_complete(c, cdata);
+		cmd_source_file_complete(cdata);
 
 	free(cwd);
 	return (retval);

cmd-split-window.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-split-window.c,v 1.148 2026/08/07 08:10:53 nicm Exp $ */
+/* $OpenBSD: cmd-split-window.c,v 1.150 2026/08/20 09:19:24 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -40,8 +40,8 @@ const struct cmd_entry cmd_new_pane_entry = {
 	.name = "new-pane",
 	.alias = "newp",
 
-	.args = { "bB:Cc:de:EfF:hIkl:LMm:Op:PR:s:S:t:T:vWx:X:y:Y:Z", 0, -1, NULL },
-	.usage = "[-bCdefhIklMOPvWZ] [-B border-lines] "
+	.args = { "AbB:Cc:de:EfF:hIkl:KLMm:Op:PR:s:S:t:T:vWx:X:y:Y:Z", 0, -1, NULL },
+	.usage = "[-AbCdefhIkKLMOPvWZ] [-B border-lines] "
 		 "[-c start-directory] [-e environment] "
 		 "[-F format] [-l size] [-m message] [-p percentage] "
 		 "[-s style] [-S active-border-style] "
@@ -89,6 +89,7 @@ cmd_split_window_exec(struct cmd *self, struct cmdq_item *item)
 	struct cmd_find_state	 fs;
 	struct key_event	*event = cmdq_get_event(item);
 	int			 input, empty, is_floating, flags = 0;
+	int			 restore_zoom = 0;
 	const char		*template, *style, *value;
 	char			*cause = NULL, *cp, *title;
 	const struct options_table_entry *oe;
@@ -96,10 +97,16 @@ cmd_split_window_exec(struct cmd *self, struct cmdq_item *item)
 	enum pane_lines		 lines;
 	u_int			 count = args_count(args);
 
+	if (window_active_pane_is_over_zoom(w))
+		restore_zoom = 1;
+
 	if (cmd_get_entry(self) == &cmd_new_pane_entry)
 		is_floating = !args_has(args, 'L');
 	else {
-		window_unzoom(w, 1);
+		if (!window_pane_is_visible(wp))
+			restore_zoom = 0;
+		if (!restore_zoom)
+			window_unzoom(w, 1);
 		is_floating = window_pane_is_floating(wp);
 		flags |= SPAWN_SPLIT;
 	}
@@ -133,7 +140,11 @@ cmd_split_window_exec(struct cmd *self, struct cmdq_item *item)
 	if (args_has(args, 'Z'))
 		flags |= SPAWN_ZOOM;
 	if (args_has(args, 'O'))
-		flags |= SPAWN_MODAL;
+		flags |= SPAWN_MODAL|SPAWN_FLOATOVERZOOM;
+	if (is_floating && args_has(args, 'A'))
+		flags |= SPAWN_FLOATOVERZOOM;
+	if ((w->flags & WINDOW_ZOOMED) && (flags & SPAWN_FLOATOVERZOOM))
+		restore_zoom = 1;
 
 	input = args_has(args, 'I');
 	if (input || (count == 1 && *args_string(args, 0) == '\0'))
@@ -169,6 +180,8 @@ cmd_split_window_exec(struct cmd *self, struct cmdq_item *item)
 	if (cause != NULL) {
 		cmdq_error(item, "%s", cause);
 		free(cause);
+		if (restore_zoom)
+			window_pop_zoom(w);
 		return (CMD_RETURN_ERROR);
 	}
 
@@ -202,6 +215,8 @@ cmd_split_window_exec(struct cmd *self, struct cmdq_item *item)
 		 */
 		goto fail;
 	}
+	if (args_has(args, 'K') && args_has(args, 'O'))
+		new_wp->flags |= PANE_CAPTUREALLKEYS;
 	if (args_has(args, 'C') && args_has(args, 'O'))
 		new_wp->flags |= PANE_CLOSEONCLICK;
 
@@ -271,7 +286,10 @@ cmd_split_window_exec(struct cmd *self, struct cmdq_item *item)
 	if (~flags & SPAWN_DETACHED)
 		cmd_find_from_winlink_pane(current, wl, new_wp, 0);
 
-	if ((~flags & SPAWN_FLOATING) && !args_has(args, 'O')) {
+	if (restore_zoom) {
+		window_pop_zoom(wp->window);
+		server_redraw_window(wp->window);
+	} else if ((~flags & SPAWN_FLOATING) && !args_has(args, 'O')) {
 		window_pop_zoom(wp->window);
 		server_redraw_window(wp->window);
 	}
@@ -322,8 +340,9 @@ fail:
 		if (!is_floating)
 			layout_close_pane(new_wp);
 		window_remove_pane(wp->window, new_wp);
-	} else if (args_has(args, 'O'))
-		window_pop_modal_zoom(wp->window);
+	}
+	if (restore_zoom || (~flags & SPAWN_FLOATING))
+		window_pop_zoom(wp->window);
 	if (sc.argv != NULL)
 		cmd_free_argv(sc.argc, sc.argv);
 	environ_free(sc.environ);

cmd-switch-client.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-switch-client.c,v 1.74 2026/05/22 15:22:43 nicm Exp $ */
+/* $OpenBSD: cmd-switch-client.c,v 1.75 2026/08/20 09:19:24 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -53,7 +53,7 @@ cmd_switch_client_exec(struct cmd *self, struct cmdq_item *item)
 	struct cmd_find_state	 target;
 	const char		*tflag = args_get(args, 't');
 	enum cmd_find_type	 type;
-	int			 flags;
+	int			 flags, visible, Zflag = args_has(args, 'Z');
 	struct client		*c = cmdq_get_client(item);
 	struct client		*tc = cmdq_get_target_client(item);
 	struct session		*s;
@@ -139,11 +139,15 @@ cmd_switch_client_exec(struct cmd *self, struct cmdq_item *item)
 			return (CMD_RETURN_NORMAL);
 		if (wl != NULL && wp != NULL && wp != wl->window->active) {
 			w = wl->window;
-			if (window_push_zoom(w, 0, args_has(args, 'Z')))
+			if (w->modal != NULL && wp != w->modal)
+				visible = 1;
+			else
+				visible = window_pane_is_visible(wp);
+			if (!visible && window_push_zoom(w, 0, Zflag))
 				server_redraw_window(w);
 			window_redraw_active_switch(w, wp);
 			window_set_active_pane(w, wp, 1);
-			if (window_pop_zoom(w))
+			if (!visible && window_pop_zoom(w))
 				server_redraw_window(w);
 		}
 		if (wl != NULL) {

configure.ac

@@ -1,6 +1,6 @@
 # configure.ac
 
-AC_INIT([tmux], next-3.8)
+AC_INIT([tmux], 3.8-rc)
 AC_PREREQ([2.60])
 
 AC_CONFIG_AUX_DIR(etc)

control-notify.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: control-notify.c,v 1.38 2026/08/03 13:38:42 nicm Exp $ */
+/* $OpenBSD: control-notify.c,v 1.39 2026/09/08 10:20:08 nicm Exp $ */
 
 /*
  * Copyright (c) 2012 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -70,6 +70,7 @@ control_window_layout_changed_cb(__unused const char *name,
 	struct session		*s;
 	struct winlink		*wl;
 	struct window		*w = event_payload_get_window(ep, "window");
+	struct format_tree	*ft;
 	const char		*template;
 	char			*cp;
 
@@ -84,19 +85,25 @@ control_window_layout_changed_cb(__unused const char *name,
 	 * and we don't need to inform the client about the layout change
 	 * because the whole window will go away soon.
 	 */
-	wl = TAILQ_FIRST(&w->winlinks);
-	if (wl == NULL || w->layout_root == NULL)
+	if (TAILQ_FIRST(&w->winlinks) == NULL || w->layout_root == NULL)
 		return;
-	cp = format_single(NULL, template, NULL, NULL, wl, NULL);
 
 	TAILQ_FOREACH(c, &clients, entry) {
 		if (!CONTROL_SHOULD_NOTIFY_CLIENT(c) || c->session == NULL)
 			continue;
 		s = c->session;
-		if (winlink_find_by_window_id(&s->windows, w->id) != NULL)
-			control_notify_write(c, "%s", cp);
+		wl = winlink_find_by_window_id(&s->windows, w->id);
+		if (wl == NULL)
+			continue;
+
+		ft = format_create(c, NULL, FORMAT_NONE, 0);
+		format_defaults(ft, c, s, wl, NULL);
+		cp = format_expand(ft, template);
+		format_free(ft);
+
+		control_notify_write(c, "%s", cp);
+		free(cp);
 	}
-	free(cp);
 }
 
 /* Notify control clients that window pane changed. */

control.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: control.c,v 1.65 2026/08/04 11:18:22 nicm Exp $ */
+/* $OpenBSD: control.c,v 1.68 2026/09/09 08:30:05 nicm Exp $ */
 
 /*
  * Copyright (c) 2012 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -108,6 +108,7 @@ struct control_state {
 	u_int				 pending_count;
 
 	TAILQ_HEAD(, control_block)	 all_blocks;
+	size_t				 queued_reply_bytes;
 
 	struct bufferevent		*read_event;
 	struct bufferevent		*write_event;
@@ -132,6 +133,9 @@ struct control_state {
 /* Maximum age for clients that are not using pause mode. */
 #define CONTROL_MAXIMUM_AGE 300000
 
+/* Maximum buffered command replies for a client that is not reading. */
+#define CONTROL_MAXIMUM_REPLY_BUFFER (64 * 1024 * 1024)
+
 /* Flags to ignore client. */
 #define CONTROL_IGNORE_FLAGS \
 	(CLIENT_CONTROL_NOOUTPUT| \
@@ -165,6 +169,15 @@ RB_GENERATE_STATIC(control_windows, control_window, entry, control_window_cmp);
 static void
 control_free_block(struct control_state *cs, struct control_block *cb)
 {
+	size_t	 size;
+
+	if (cb->size == 0 && cb->line != NULL) {
+		size = strlen(cb->line) + 1;
+		if (cs->queued_reply_bytes > size)
+			cs->queued_reply_bytes -= size;
+		else
+			cs->queued_reply_bytes = 0;
+	}
 	free(cb->line);
 	TAILQ_REMOVE(&cs->all_blocks, cb, all_entry);
 	free(cb);
@@ -388,16 +401,71 @@ control_pause_pane(struct client *c, struct window_pane *wp)
 	}
 }
 
+/*
+ * Reset a pane after its buffer has been replaced: drop any output still
+ * queued from the old buffer and start again from the pane's own offset.
+ */
+void
+control_reset_pane(struct client *c, struct window_pane *wp)
+{
+	struct control_pane	*cp;
+
+	if (c->control_state == NULL)
+		return;
+	cp = control_get_pane(c, wp);
+	if (cp == NULL)
+		return;
+	control_discard_pane(c, cp);
+	memcpy(&cp->offset, &wp->offset, sizeof cp->offset);
+	memcpy(&cp->queued, &wp->offset, sizeof cp->queued);
+}
+
+/*
+ * Check if the replies buffered for a client, including one about to be
+ * added, have grown too large and kill it if so. Returns 1 if further output
+ * for the client should be dropped.
+ */
+static int
+control_check_reply_buffer(struct client *c, size_t added)
+{
+	struct control_state	*cs = c->control_state;
+	size_t			 size;
+
+	if (c->flags & CLIENT_CONTROL_DISCARD)
+		return (1);
+	size = EVBUFFER_LENGTH(cs->write_event->output);
+	size += cs->queued_reply_bytes;
+	size += added;
+	if (size < CONTROL_MAXIMUM_REPLY_BUFFER)
+		return (0);
+
+	log_debug("%s: %s: %zu bytes of replies buffered", __func__, c->name,
+	    size);
+	if (~c->flags & CLIENT_EXIT) {
+		c->exit_message = xstrdup("too far behind");
+		c->flags |= CLIENT_EXIT;
+		control_discard(c);
+	}
+	c->flags |= CLIENT_CONTROL_DISCARD;
+	return (1);
+}
+
 /* Write an already-formatted line, queueing it behind %output if needed. */
 static void
 control_write_line(struct client *c, char *line)
 {
 	struct control_state	*cs = c->control_state;
 	struct control_block	*cb;
+	size_t			 size = strlen(line) + 1;
+
+	if (control_check_reply_buffer(c, size)) {
+		free(line);
+		return;
+	}
 
 	if (TAILQ_EMPTY(&cs->all_blocks)) {
 		log_debug("%s: %s: writing line: %s", __func__, c->name, line);
-		bufferevent_write(cs->write_event, line, strlen(line));
+		bufferevent_write(cs->write_event, line, size - 1);
 		bufferevent_write(cs->write_event, "\n", 1);
 		bufferevent_enable(cs->write_event, EV_WRITE);
 		free(line);
@@ -407,6 +475,7 @@ control_write_line(struct client *c, char *line)
 	cb = xcalloc(1, sizeof *cb);
 	cb->line = line;
 	TAILQ_INSERT_TAIL(&cs->all_blocks, cb, all_entry);
+	cs->queued_reply_bytes += size;
 	cb->t = get_timer();
 
 	log_debug("%s: %s: storing line: %s", __func__, c->name, cb->line);
@@ -436,8 +505,12 @@ control_flush_deferred(struct client *c)
 void
 control_write(struct client *c, const char *fmt, ...)
 {
-	va_list	 ap;
-	char	*line;
+	struct control_state	*cs = c->control_state;
+	char			*line;
+	va_list			 ap;
+
+	if (cs == NULL)
+		return;
 
 	va_start(ap, fmt);
 	xvasprintf(&line, fmt, ap);
@@ -460,6 +533,9 @@ control_write_guard(struct client *c, const char *guard, long t, u_int number,
 	struct control_state	*cs = c->control_state;
 	char			*line;
 
+	if (cs == NULL)
+		return;
+
 	if (strcmp(guard, "begin") == 0)
 		cs->guard_depth++;
 
@@ -484,6 +560,9 @@ control_notify_write(struct client *c, const char *fmt, ...)
 	va_list			 ap;
 	char			*line;
 
+	if (cs == NULL)
+		return;
+
 	va_start(ap, fmt);
 	xvasprintf(&line, fmt, ap);
 	va_end(ap);
@@ -978,6 +1057,7 @@ control_discard_all(struct client *c)
 	control_discard(c);
 	TAILQ_FOREACH_SAFE(cb, &cs->all_blocks, all_entry, cb1)
 		control_free_block(cs, cb);
+	cs->queued_reply_bytes = 0;
 	bufferevent_disable(cs->write_event, EV_WRITE);
 }
 

format.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: format.c,v 1.412 2026/08/05 07:31:08 nicm Exp $ */
+/* $OpenBSD: format.c,v 1.417 2026/09/08 15:42:26 nicm Exp $ */
 
 /*
  * Copyright (c) 2011 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -855,26 +855,42 @@ format_cb_window_active_clients_list(struct format_tree *ft)
 static void *
 format_cb_window_layout(struct format_tree *ft)
 {
-	struct window	*w = ft->w;
+	struct client		*c = ft->client;
+	struct window		*w = ft->w;
+	struct layout_cell	*lcroot;
+	int			 flags = 0;
 
 	if (w == NULL)
 		return (NULL);
 
 	if (w->saved_layout_root != NULL)
-		return (layout_dump(w, w->saved_layout_root));
-	return (layout_dump(w, w->layout_root));
+		lcroot = w->saved_layout_root;
+	else
+		lcroot = w->layout_root;
+
+	if (c != NULL &&
+	    (c->flags & CLIENT_CONTROL) &&
+	    (~c->flags & CLIENT_CONTROL_NEWLAYOUTS))
+		flags |= LAYOUT_CUSTOM_OLD_FORMAT;
+	return (layout_dump(w, lcroot, flags));
 }
 
 /* Callback for window_visible_layout. */
 static void *
 format_cb_window_visible_layout(struct format_tree *ft)
 {
+	struct client	*c = ft->client;
 	struct window	*w = ft->w;
+	int		 flags = 0;
 
 	if (w == NULL)
 		return (NULL);
 
-	return (layout_dump(w, w->layout_root));
+	if (c != NULL &&
+	    (c->flags & CLIENT_CONTROL) &&
+	    (~c->flags & CLIENT_CONTROL_NEWLAYOUTS))
+		flags |= LAYOUT_CUSTOM_OLD_FORMAT;
+	return (layout_dump(w, w->layout_root, flags));
 }
 
 /* Callback for pane_start_command. */
@@ -1887,6 +1903,37 @@ format_cb_cursor_blinking(struct format_tree *ft)
 	return (NULL);
 }
 
+/* Callback for history_added. */
+static void *
+format_cb_history_added(struct format_tree *ft)
+{
+	if (ft->wp != NULL)
+		return (format_printf("%u", ft->wp->base.grid->scroll_added));
+	return (NULL);
+}
+
+/* Callback for history_collected. */
+static void *
+format_cb_history_collected(struct format_tree *ft)
+{
+	struct window_pane	*wp = ft->wp;
+
+	if (wp != NULL)
+		return (format_printf("%u", wp->base.grid->scroll_collected));
+	return (NULL);
+}
+
+/* Callback for history_generation. */
+static void *
+format_cb_history_generation(struct format_tree *ft)
+{
+	struct window_pane	*wp = ft->wp;
+
+	if (wp != NULL)
+		return (format_printf("%u", wp->base.grid->scroll_generation));
+	return (NULL);
+}
+
 /* Callback for history_limit. */
 static void *
 format_cb_history_limit(struct format_tree *ft)
@@ -2276,6 +2323,19 @@ format_cb_pane_last_output_time(struct format_tree *ft)
 	return (NULL);
 }
 
+/* Callback for pane_output_generation. */
+static void *
+format_cb_pane_output_generation(struct format_tree *ft)
+{
+	unsigned long long	 value;
+
+	if (ft->wp != NULL) {
+		value = ft->wp->output_generation;
+		return (format_printf("%llu", value));
+	}
+	return (NULL);
+}
+
 /* Callback for pane_last_prompt_time. */
 static void *
 format_cb_pane_last_prompt_time(struct format_tree *ft)
@@ -3663,12 +3723,21 @@ static const struct format_table_entry format_table[] = {
 	{ "cursor_y", FORMAT_TABLE_STRING,
 	  format_cb_cursor_y
 	},
+	{ "history_added", FORMAT_TABLE_STRING,
+	  format_cb_history_added
+	},
 	{ "history_all_bytes", FORMAT_TABLE_STRING,
 	  format_cb_history_all_bytes
 	},
 	{ "history_bytes", FORMAT_TABLE_STRING,
 	  format_cb_history_bytes
 	},
+	{ "history_collected", FORMAT_TABLE_STRING,
+	  format_cb_history_collected
+	},
+	{ "history_generation", FORMAT_TABLE_STRING,
+	  format_cb_history_generation
+	},
 	{ "history_limit", FORMAT_TABLE_STRING,
 	  format_cb_history_limit
 	},
@@ -3849,6 +3918,9 @@ static const struct format_table_entry format_table[] = {
 	{ "pane_mode", FORMAT_TABLE_STRING,
 	  format_cb_pane_mode
 	},
+	{ "pane_output_generation", FORMAT_TABLE_STRING,
+	  format_cb_pane_output_generation
+	},
 	{ "pane_path", FORMAT_TABLE_STRING,
 	  format_cb_pane_path
 	},
@@ -4387,7 +4459,7 @@ format_quote_shell(const char *s)
 
 	at = out = xmalloc(strlen(s) * 2 + 1);
 	for (cp = s; *cp != '\0'; cp++) {
-		if (strchr("|&;<>()$`\\\"'*?[# =%\n\t", *cp) != NULL)
+		if (strchr("|&;<>(){}$`\\\"'*?[# =%\n\t", *cp) != NULL)
 			*at++ = '\\';
 		*at++ = *cp;
 	}
@@ -5178,6 +5250,7 @@ format_loop_sessions(struct format_expand_state *es, const char *fmt)
 		format_log(es, "session loop: $%u", s->id);
 		if (active != NULL &&
 		    ft->c != NULL &&
+		    ft->c->session != NULL &&
 		    s->id == ft->c->session->id)
 			use = active;
 		else

grid.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: grid.c,v 1.156 2026/08/03 12:58:53 nicm Exp $ */
+/* $OpenBSD: grid.c,v 1.158 2026/09/01 12:49:49 nicm Exp $ */
 
 /*
  * Copyright (c) 2008 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -1635,7 +1635,7 @@ grid_wrap_position(struct grid *gd, u_int px, u_int py, u_int *wx, u_int *wy)
 void
 grid_unwrap_position(struct grid *gd, u_int *px, u_int *py, u_int wx, u_int wy)
 {
-	u_int	yy, ay = 0;
+	u_int	yy, ay = 0, ey = gd->hsize + gd->sy - 1;
 
 	for (yy = 0; yy < gd->hsize + gd->sy - 1; yy++) {
 		if (ay == wy)
@@ -1649,7 +1649,7 @@ grid_unwrap_position(struct grid *gd, u_int *px, u_int *py, u_int wx, u_int wy)
 	 * until we find the end or the line now containing wx.
 	 */
 	if (wx == UINT_MAX) {
-		while (gd->linedata[yy].flags & GRID_LINE_WRAPPED)
+		while (yy < ey && gd->linedata[yy].flags & GRID_LINE_WRAPPED)
 			yy++;
 		wx = gd->linedata[yy].cellused;
 	} else {
@@ -1711,21 +1711,29 @@ grid_in_set(struct grid *gd, u_int px, u_int py, const char *set)
 {
 	struct grid_cell	gc, tmp_gc;
 	u_int			pxx;
+	int			has_tab, has_space;
+
+	has_tab = (strchr(set, '\t') != NULL);
+	has_space = (strchr(set, ' ') != NULL);
 
 	grid_get_cell(gd, px, py, &gc);
-	if (strchr(set, '\t')) {
-		if (gc.flags & GRID_FLAG_PADDING) {
-			pxx = px;
-			do
-				grid_get_cell(gd, --pxx, py, &tmp_gc);
-			while (pxx > 0 && tmp_gc.flags & GRID_FLAG_PADDING);
-			if (tmp_gc.flags & GRID_FLAG_TAB)
-				return (tmp_gc.data.width - (px - pxx));
-		} else if (gc.flags & GRID_FLAG_TAB)
-			return (gc.data.width);
-	}
-	if (gc.flags & GRID_FLAG_PADDING)
+	if (gc.flags & GRID_FLAG_PADDING) {
+		if (!has_tab && !has_space)
+			return (0);
+		pxx = px;
+		do
+			grid_get_cell(gd, --pxx, py, &tmp_gc);
+		while (pxx > 0 && tmp_gc.flags & GRID_FLAG_PADDING);
+		if (((has_tab || has_space) &&
+		    (tmp_gc.flags & GRID_FLAG_TAB)) ||
+		    (has_space && utf8_has_whitespace(&tmp_gc.data)))
+			return (tmp_gc.data.width - (px - pxx));
 		return (0);
+	}
+	if ((has_tab || has_space) && (gc.flags & GRID_FLAG_TAB))
+		return (gc.data.width);
+	if (has_space && utf8_has_whitespace(&gc.data))
+		return (gc.data.width == 0 ? 1 : gc.data.width);
 	return (utf8_cstrhas(set, &gc.data));
 }
 

image.c

@@ -84,6 +84,11 @@ image_fallback(char **ret, u_int sx, u_int sy)
 	char	*buf, *label;
 	u_int	 py, size, lsize;
 
+	if (sy == 0) {
+		*ret = xstrdup("");
+		return;
+	}
+
 	/* Allocate first line. */
 	lsize = xasprintf(&label, "SIXEL IMAGE (%ux%u)\r\n", sx, sy) + 1;
 	if (sx < lsize - 3)

input.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: input.c,v 1.269 2026/07/20 11:16:33 nicm Exp $ */
+/* $OpenBSD: input.c,v 1.271 2026/08/31 19:34:09 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -1049,6 +1049,7 @@ input_parse_buffer(struct window_pane *wp, const u_char *buf, size_t len)
 	if (len == 0)
 		return;
 
+	wp->output_generation++;
 	window_update_activity(wp->window);
 	if (~wp->flags & PANE_ACTIVITY) {
 		wp->flags |= PANE_ACTIVITY;
@@ -1978,7 +1979,7 @@ input_csi_dispatch_rm_private(struct input_ctx *ictx)
 			screen_write_mode_clear(sctx, MODE_BRACKETPASTE);
 			break;
 		case 2026:
-			screen_write_stop_sync(ictx->wp);
+			screen_write_end_sync(sctx);
 			break;
 		case 2031:
 			screen_write_mode_clear(sctx, MODE_THEME_UPDATES);

layout.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: layout.c,v 1.96 2026/07/15 13:02:33 nicm Exp $ */
+/* $OpenBSD: layout.c,v 1.99 2026/09/09 07:03:39 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -106,7 +106,7 @@ layout_free_cell(struct layout_cell *lc, int only_nodes)
 		}
 		break;
 	case LAYOUT_WINDOWPANE:
-		if (lc->wp != NULL) {
+		if (lc->wp != NULL && lc->wp->layout_cell != NULL) {
 			lc->wp->layout_cell->parent = NULL;
 			lc->wp->layout_cell = NULL;
 		}
@@ -233,29 +233,6 @@ layout_make_node(struct layout_cell *lc, enum layout_type type)
 	lc->wp = NULL;
 }
 
-/* Fix z-indexes. */
-void
-layout_fix_zindexes(struct window *w, struct layout_cell *lc)
-{
-	struct layout_cell	*lcchild;
-
-	if (lc == NULL)
-		return;
-
-	switch (lc->type) {
-	case LAYOUT_WINDOWPANE:
-		TAILQ_INSERT_TAIL(&w->z_index, lc->wp, zentry);
-		break;
-	case LAYOUT_LEFTRIGHT:
-	case LAYOUT_TOPBOTTOM:
-		TAILQ_FOREACH(lcchild, &lc->cells, entry)
-			layout_fix_zindexes(w, lcchild);
-		return;
-	default:
-		fatalx("bad layout type");
-	}
-}
-
 int
 layout_cell_is_tiled(struct layout_cell *lc)
 {
@@ -265,7 +242,7 @@ layout_cell_is_tiled(struct layout_cell *lc)
 	return is_leaf && !is_floating;
 }
 
-static int
+int
 layout_cell_has_tiled_child(struct layout_cell *lc)
 {
 	struct layout_cell      *lcchild;
@@ -509,18 +486,20 @@ layout_fix_panes(struct window *w, struct window_pane *skip)
 
 /* Count the number of available cells in a layout. */
 u_int
-layout_count_cells(struct layout_cell *lc)
+layout_count_cells(struct layout_cell *lc, int with_floating)
 {
 	struct layout_cell	*lcchild;
 	u_int			 count = 0;
 
 	switch (lc->type) {
 	case LAYOUT_WINDOWPANE:
+		if (lc->flags & LAYOUT_CELL_FLOATING && !with_floating)
+			return 0;
 		return (1);
 	case LAYOUT_LEFTRIGHT:
 	case LAYOUT_TOPBOTTOM:
 		TAILQ_FOREACH(lcchild, &lc->cells, entry)
-			count += layout_count_cells(lcchild);
+			count += layout_count_cells(lcchild, with_floating);
 		return (count);
 	default:
 		fatalx("bad layout type");
@@ -539,6 +518,10 @@ layout_resize_check(struct window *w, struct layout_cell *lc,
 
 	status = window_get_pane_status(w);
 
+	/* Floating cells do not take space from the tiled layout. */
+	if (!layout_cell_is_tiled(lc) && !layout_cell_has_tiled_child(lc))
+		return (0);
+
 	if (lc->type == LAYOUT_WINDOWPANE) {
 		/* Space available in this cell only. */
 		if (type == LAYOUT_LEFTRIGHT) {
@@ -568,6 +551,9 @@ layout_resize_check(struct window *w, struct layout_cell *lc,
 		/* Different type: minimum of available space in child cells. */
 		minimum = UINT_MAX;
 		TAILQ_FOREACH(lcchild, &lc->cells, entry) {
+			if (!layout_cell_is_tiled(lcchild) &&
+			    !layout_cell_has_tiled_child(lcchild))
+				continue;
 			available = layout_resize_check(w, lcchild, type);
 			if (available < minimum)
 				minimum = available;
@@ -661,7 +647,7 @@ layout_resize_set_size(struct window *w, struct layout_cell *lc,
 
 /* Find and return the nearest neighbour to a cell in a specific direction. */
 static struct layout_cell *
-layout_cell_get_neighbour_direction(struct layout_cell *lc, int direction)
+layout_cell_get_neighbour_dir(struct layout_cell *lc, int direction)
 {
 	struct layout_cell	*lcn = lc;
 
@@ -695,9 +681,9 @@ layout_cell_get_neighbour(struct layout_cell *lc)
 	if (lc == TAILQ_LAST(&lcparent->cells, layout_cells))
 		direction = !direction;
 
-	lcother = layout_cell_get_neighbour_direction(lc, direction);
+	lcother = layout_cell_get_neighbour_dir(lc, direction);
 	if (lcother == NULL)
-		lcother = layout_cell_get_neighbour_direction(lc, !direction);
+		lcother = layout_cell_get_neighbour_dir(lc, !direction);
 
 	return (lcother);
 }
@@ -714,7 +700,7 @@ layout_destroy_cell(struct window *w, struct layout_cell *lc,
 	/* If no parent, this is the last pane in a window. */
 	lcparent = lc->parent;
 	if (lcparent == NULL) {
-		if (lc->wp != NULL)
+		if (*lcroot == lc)
 			*lcroot = NULL;
 		layout_free_cell(lc, 0);
 		return;
@@ -860,7 +846,7 @@ layout_resize_pane_to(struct window_pane *wp, enum layout_type type,
 		size = lc->g.sx;
 	else
 		size = lc->g.sy;
-	if (lc == TAILQ_LAST(&lcparent->cells, layout_cells))
+	if (layout_cell_is_last_tiled(lc))
 		change = size - new_size;
 	else
 		change = new_size - size;
@@ -985,11 +971,11 @@ layout_resize_pane(struct window_pane *wp, enum layout_type type, int change,
 	if (lcparent == NULL)
 		return;
 
-	/* If this is the last cell, move back one. */
-	if (lc == TAILQ_LAST(&lcparent->cells, layout_cells)) {
-		do
-			lc = TAILQ_PREV(lc, layout_cells, entry);
-		while (lc->flags & LAYOUT_CELL_FLOATING);
+	/* If this is the last tiled cell, move back one. */
+	if (layout_cell_is_last_tiled(lc)) {
+		lc = layout_cell_get_neighbour_dir(lc, 0);
+		if (lc == NULL)
+			return;
 	}
 
 	layout_resize_layout(wp->window, lc, type, change, opposite);
@@ -1007,22 +993,22 @@ layout_resize_pane_grow(struct window *w, struct layout_cell *lc,
 	lcadd = lc;
 
 	/* Look towards the tail for a suitable cell for reduction. */
-	lcremove = TAILQ_NEXT(lc, entry);
+	lcremove = layout_cell_get_neighbour_dir(lc, 1);
 	while (lcremove != NULL) {
 		size = layout_resize_check(w, lcremove, type);
 		if (size > 0)
 			break;
-		lcremove = TAILQ_NEXT(lcremove, entry);
+		lcremove = layout_cell_get_neighbour_dir(lcremove, 1);
 	}
 
 	/* If none found, look towards the head. */
 	if (opposite && lcremove == NULL) {
-		lcremove = TAILQ_PREV(lc, layout_cells, entry);
+		lcremove = layout_cell_get_neighbour_dir(lc, 0);
 		while (lcremove != NULL) {
 			size = layout_resize_check(w, lcremove, type);
 			if (size > 0)
 				break;
-			lcremove = TAILQ_PREV(lcremove, layout_cells, entry);
+			lcremove = layout_cell_get_neighbour_dir(lcremove, 0);
 		}
 	}
 	if (lcremove == NULL)
@@ -1050,13 +1036,13 @@ layout_resize_pane_shrink(struct window *w, struct layout_cell *lc,
 		size = layout_resize_check(w, lcremove, type);
 		if (size != 0)
 			break;
-		lcremove = TAILQ_PREV(lcremove, layout_cells, entry);
+		lcremove = layout_cell_get_neighbour_dir(lcremove, 0);
 	} while (lcremove != NULL);
 	if (lcremove == NULL)
 		return (0);
 
 	/* And add onto the next cell (from the original cell). */
-	lcadd = TAILQ_NEXT(lc, entry);
+	lcadd = layout_cell_get_neighbour_dir(lc, 1);
 	if (lcadd == NULL)
 		return (0);
 
@@ -1650,7 +1636,10 @@ layout_get_tiled_cell(struct cmdq_item *item, struct args *args,
 		return (NULL);
 	}
 
-	window_push_zoom(wp->window, 1, (flags & SPAWN_ZOOM));
+	if (window_active_pane_is_over_zoom(w))
+		window_push_zoom(w, 0, 1);
+	else
+		window_push_zoom(w, 1, (flags & SPAWN_ZOOM));
 	lc = layout_split_pane(wp, type, size, flags);
 	if (lc == NULL)
 		*cause = xstrdup("no space for a new pane");
@@ -1677,8 +1666,10 @@ layout_get_floating_cell(struct cmdq_item *item, struct args *args,
 			return (NULL);
 	}
 
-	if (flags & SPAWN_MODAL)
-		window_push_modal_zoom(w);
+	if (flags & SPAWN_FLOATOVERZOOM)
+		window_push_zoom(wp->window, 0, 1);
+	else if (window_active_pane_is_over_zoom(w))
+		window_push_zoom(wp->window, 0, 1);
 	else
 		window_push_zoom(wp->window, 1, (flags & SPAWN_ZOOM));
 	lcnew = layout_floating_pane(w, wp, &fg);

monitor.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: monitor.c,v 1.7 2026/07/27 19:15:58 nicm Exp $ */
+/* $OpenBSD: monitor.c,v 1.8 2026/09/07 10:15:25 nicm Exp $ */
 
 /*
  * Copyright (c) 2026 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -614,8 +614,10 @@ monitor_parse(const char *value, char **name, enum monitor_type *type, int *id,
 		*type = MONITOR_ALL_WINDOWS;
 	else if (sscanf(what, "@%d", id) == 1 && *id >= 0)
 		*type = MONITOR_WINDOW;
-	else
+	else if (*what == '\0')
 		*type = MONITOR_SESSION;
+	else
+		goto fail;
 	*name = xstrdup(copy);
 	*format = xstrdup(split);
 

options-table.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: options-table.c,v 1.242 2026/07/27 08:03:01 nicm Exp $ */
+/* $OpenBSD: options-table.c,v 1.244 2026/09/01 12:49:49 nicm Exp $ */
 
 /*
  * Copyright (c) 2011 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -305,6 +305,16 @@ const struct options_table_entry options_table[] = {
 		  "When this is reached, the oldest buffer is deleted."
 	},
 
+	{ .name = "clear-on-attach",
+	  .type = OPTIONS_TABLE_FLAG,
+	  .scope = OPTIONS_TABLE_SERVER,
+	  .default_num = 1,
+	  .text = "Whether to use the alternate screen and clear it when "
+		  "a client is attached. When disabled, tmux does not "
+		  "enter the alternate screen on attach so terminal "
+		  "content before tmux remains in scrollback."
+	},
+
 	{ .name = "command-alias",
 	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_SERVER,
@@ -1240,7 +1250,8 @@ const struct options_table_entry options_table[] = {
 	   * underscore.
 	   */
 	  .default_str = "!\"#$%&'()*+,-./:;<=>?@[\\]^`{|}~",
-	  .text = "Characters considered to separate words."
+	  .text = "Characters considered to separate words; a space matches "
+		  "any character with the Unicode White_Space property."
 	},
 
 	/* Window options. */

popup.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: popup.c,v 1.76 2026/07/14 19:07:03 nicm Exp $ */
+/* $OpenBSD: popup.c,v 1.77 2026/08/28 08:02:16 nicm Exp $ */
 
 /*
  * Copyright (c) 2020 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -79,7 +79,8 @@ popup_free(struct popup_data *pd)
 
 	if (pd->job != NULL)
 		job_free(pd->job);
-	input_free(pd->ictx);
+	if (pd->ictx != NULL)
+		input_free(pd->ictx);
 
 	free(pd->r.ranges);
 	screen_free(&pd->s);

prompt.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: prompt.c,v 1.6 2026/08/17 06:45:16 nicm Exp $ */
+/* $OpenBSD: prompt.c,v 1.7 2026/09/09 07:53:03 nicm Exp $ */
 
 /*
  * Copyright (c) 2026 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -1493,9 +1493,11 @@ append_key:
 		utf8_set(&tmp, key);
 		if (key <= 0x1f || key == 0x7f)
 			tmp.width = 2;
-	} else if (KEYC_IS_UNICODE(key))
+	} else if (KEYC_IS_UNICODE(key)) {
 		utf8_to_data(key, &tmp);
-	else
+		if (tmp.size == 0)
+			return (PROMPT_KEY_HANDLED);
+	} else
 		return (PROMPT_KEY_HANDLED);
 
 	pr->buffer = xreallocarray(pr->buffer, size + 2,

regress/buffers.sh

@@ -28,7 +28,7 @@ $TMUX kill-server 2>/dev/null
 
 TMP=$(mktemp)
 TMP2=$(mktemp)
-trap 'rm -f "$TMP" "$TMP2"; $TMUX kill-server 2>/dev/null' 0 1 15
+trap 'rm -f "$TMP" "$TMP2" "$TMP".*; $TMUX kill-server 2>/dev/null' 0 1 15
 
 # check_ok $cmd...
 #
@@ -270,6 +270,27 @@ if [ $? -eq 0 ]; then
 	exit 1
 fi
 
+# A write error after a successful open must be reported to the server.
+dd if=/dev/zero of="$TMP.big" bs=100000 count=1 2>/dev/null
+check_ok load-buffer -b write-error "$TMP.big"
+mkfifo "$TMP.fifo" || exit 1
+dd if="$TMP.fifo" of="$TMP.got" bs=1 count=8 2>/dev/null &
+reader=$!
+exec 3>"$TMP.fifo"
+out=$($TMUX save-buffer -b write-error "$TMP.fifo" 3>&- 2>&1)
+status=$?
+exec 3>&-
+wait "$reader"
+if [ $status -eq 0 ]; then
+	echo "save-buffer after write error succeeded."
+	exit 1
+fi
+if [ "$(wc -c <"$TMP.got")" -ne 8 ]; then
+	echo "save-buffer write error test wrote wrong amount."
+	exit 1
+fi
+check_ok delete-buffer -b write-error
+
 # save-buffer - writes to stdout and load-buffer - reads from stdin.
 out=$($TMUX save-buffer -b sb -)
 if [ "$out" != "data" ]; then

regress/capture-pane-time.sh

@@ -0,0 +1,38 @@
+#!/bin/sh
+
+# capture-pane -I line timestamps
+
+PATH=/bin:/usr/bin
+TERM=screen
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+TMUX="$TEST_TMUX -LtestA$$ -f/dev/null"
+TMP=$(mktemp)
+trap '$TMUX kill-server 2>/dev/null; rm -f "$TMP"' 0 1 15
+$TMUX kill-server 2>/dev/null
+
+before=$(date +%s)
+$TMUX new-session -d -x 40 -y 5 'seq 1 12; sleep 10' || exit 1
+sleep 1
+after=$(date +%s)
+
+$TMUX capture-pane -pILF -S - -E - >"$TMP" || exit 1
+awk -v before="$before" -v after="$after" '
+	$1 !~ /^-?[0-9]+$/ || $2 !~ /^[0-9]+$/ { exit 1 }
+	$4 == "1" {
+		if ($2 < before || $2 > after)
+			exit 1
+		history = 1
+	}
+	$4 == "9" {
+		if ($2 != 0)
+			exit 1
+		visible = 1
+	}
+	END { if (!history || !visible) exit 1 }
+' "$TMP" || {
+	cat "$TMP"
+	exit 1
+}
+
+exit 0

regress/choose-tree.sh

@@ -290,4 +290,92 @@ wait_count ': G4' 7
 	fail "window 1 of zzz not killed"
 exit_mode q
 
+# --- help and information preview --------------------------------------------
+# The complete tree help is taller than the 24-line test terminal, where the
+# help renderer deliberately leaves the tree unchanged.
+$TMUX2 resize-window -t out:0 -x 80 -y 50 || exit 1
+i=0
+while [ "$i" -lt 50 ]; do
+	# The inner session has a one-line status, leaving a 49-line window.
+	[ "$($TMUX display-message -p -t aaa:0 '#{window_height}')" -ge 49 ] &&
+		break
+	sleep 0.2
+	i=$((i + 1))
+done
+[ "$i" -lt 50 ] || fail "attached client did not resize for tree help"
+$TMUX choose-tree -t aaa:0 -F 'G5' -O index || exit 1
+wait_count ': G5' 7
+$TMUX2 send-keys -t out:0 F1 || fail "send-keys F1 failed"
+wait_for 'Swap current and previous window'
+# The first key closes help; the second exits the tree.
+$TMUX send-keys -t aaa:0 q q || fail "send-keys help exit failed"
+wait_mode aaa:0 0
+
+$TMUX choose-tree -t aaa:0 -F 'G6' -O index || exit 1
+wait_count ': G6' 7
+$TMUX send-keys -t aaa:0 i || fail "send-keys info failed"
+wait_for 'Session'
+$TMUX send-keys -t aaa:0 i || fail "send-keys preview failed"
+exit_mode q
+
+# --- window swapping and command prompt for current/tagged items -------------
+# Restrict a window-only tree to two disposable windows in aaa. J (the
+# Shift-Down equivalent) swaps their window objects while leaving their indexes
+# in place.
+$TMUX new-window -d -t aaa: -n swap-a 'cat' || exit 1
+$TMUX new-window -d -t aaa: -n swap-b 'cat' || exit 1
+aidx=$($TMUX list-windows -t aaa -F '#{window_index}:#{window_name}' | \
+    awk -F: '$2 == "swap-a" {print $1}')
+bidx=$($TMUX list-windows -t aaa -F '#{window_index}:#{window_name}' | \
+    awk -F: '$2 == "swap-b" {print $1}')
+$TMUX choose-tree -w -t aaa:0 -O index -F 'WT #{window_name}' \
+	-f '#{m:swap-*,#{window_name}}' || exit 1
+wait_count 'WT swap-' 2
+$TMUX send-keys -t aaa:0 g j J || fail "window tree swap failed"
+i=0
+while [ "$i" -lt 50 ]; do
+	aname=$($TMUX display-message -p -t "aaa:$aidx" '#{window_name}')
+	bname=$($TMUX display-message -p -t "aaa:$bidx" '#{window_name}')
+	[ "$aname:$bname" = 'swap-b:swap-a' ] && break
+	sleep 0.2
+	i=$((i + 1))
+done
+[ "$i" -lt 50 ] || fail "window tree did not swap the two windows"
+
+# ':' runs an entered command for the current item and rebuilds the tree when
+# its queued command completes.
+$TMUX set-option -g @tree-command '' || exit 1
+$TMUX send-keys -t aaa:0 : || fail "window tree command prompt failed"
+wait_for '(current)'
+$TMUX send-keys -t aaa:0 -l "set-option -g @tree-command '%%'" || exit 1
+$TMUX send-keys -t aaa:0 Enter || exit 1
+i=0
+while [ "$i" -lt 50 ]; do
+	value=$($TMUX show-option -gqv @tree-command)
+	[ -n "$value" ] && break
+	sleep 0.2
+	i=$((i + 1))
+done
+[ "$i" -lt 50 ] || fail "window tree entered command did not run"
+case "$value" in
+=aaa:*.) ;;
+*) fail "window tree command target was '$value'" ;;
+esac
+
+# Tag both disposable windows and kill them through the tagged confirmation
+# callback. The mode-hosting window is outside the filter and survives.
+$TMUX send-keys -t aaa:0 g j t j t X || fail "tagged kill keys failed"
+wait_for 'Kill 2 tagged?'
+$TMUX send-keys -t aaa:0 y || fail "tagged kill confirmation failed"
+i=0
+while [ "$i" -lt 50 ]; do
+	left=$($TMUX list-windows -t aaa -F '#{window_name}' | \
+	    grep -c '^swap-' || true)
+	[ "$left" -eq 0 ] && break
+	sleep 0.2
+	i=$((i + 1))
+done
+[ "$i" -lt 50 ] || fail "tagged windows were not killed"
+exit_mode q
+
 exit 0

regress/clear-on-attach.sh

@@ -0,0 +1,96 @@
+#!/bin/sh
+
+# With clear-on-attach disabled tmux must preserve the terminal contents by
+# scrolling them away, rather than entering and clearing the alternate screen.
+# Capture the bytes written by a real attached client for both settings.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+INNER_ON="$TEST_TMUX -LtestIon$$ -f/dev/null"
+OUTER_ON="$TEST_TMUX -LtestOon$$ -f/dev/null"
+INNER_OFF="$TEST_TMUX -LtestIoff$$ -f/dev/null"
+OUTER_OFF="$TEST_TMUX -LtestOoff$$ -f/dev/null"
+DIR=$(mktemp -d) || exit 1
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$OUTER_ON kill-server 2>/dev/null
+	$INNER_ON kill-server 2>/dev/null
+	$OUTER_OFF kill-server 2>/dev/null
+	$INNER_OFF kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+wait_for_client()
+{
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$current_inner list-clients 2>/dev/null | grep -q . && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "inner client did not attach"
+}
+
+capture_attach()
+{
+	setting=$1
+	output=$2
+	go=$DIR/go-$setting
+	if [ "$setting" = on ]; then
+		current_inner=$INNER_ON
+		current_outer=$OUTER_ON
+	else
+		current_inner=$INNER_OFF
+		current_outer=$OUTER_OFF
+	fi
+
+	$current_inner new-session -d -s inner -x40 -y10 \
+	    'exec sleep 100' || exit 1
+	$current_inner set-option -g status off || exit 1
+	$current_inner set-option -g clear-on-attach "$setting" || exit 1
+	$current_outer new-session -d -s outer -x40 -y10 \
+	    "while [ ! -e '$go' ]; do sleep 0.01; done; exec $current_inner attach-session -t inner" || exit 1
+	$current_outer set-option -g status off || exit 1
+	$current_outer pipe-pane -O "cat >'$output'" || exit 1
+	touch "$go"
+	wait_for_client
+	sleep 0.5
+	$current_outer pipe-pane -O || exit 1
+}
+
+on=$DIR/on
+off=$DIR/off
+capture_attach on "$on"
+capture_attach off "$off"
+
+smcup=$(printf '\033[?1049h')
+grep -Fq "$smcup" "$on" || fail "clear-on-attach on did not use smcup"
+if grep -Fq "$smcup" "$off"; then
+	fail "clear-on-attach off used smcup"
+fi
+
+# Some screen terminfo entries have indn (CSI Ps S), while older ones only
+# have ind (newline). The preserving path uses indn once or repeats ind once
+# for every line in the terminal plus one.
+escape=$(printf '\033')
+if ! LC_ALL=C grep -Eq "${escape}\\[[0-9]+S" "$off"; then
+	hex=$(od -An -tx1 -v "$off" | tr -d ' \n')
+	case "$hex" in
+	*0a0a0a0a0a0a0a0a0a0a0a*) ;;
+	*) fail "clear-on-attach off did not scroll the old contents away" ;;
+	esac
+fi
+
+exit 0

regress/client-key-order-focus.sh

@@ -0,0 +1,82 @@
+#!/bin/sh
+
+# send-keys -K injects a key into a client. Commands produced by that key must
+# be inserted immediately after send-keys, before later commands in the same
+# command list. Focus events arriving between a prefix and its following key
+# must be forwarded without cancelling the prefix table.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+INNER="$TEST_TMUX -LtestI$$ -f/dev/null"
+OUTER="$TEST_TMUX -LtestO$$ -f/dev/null"
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$OUTER kill-server 2>/dev/null
+	$INNER kill-server 2>/dev/null
+}
+trap cleanup 0 1 15
+
+wait_for_client()
+{
+	i=0
+	while [ "$i" -lt 50 ]; do
+		client=$($INNER list-clients -F '#{client_name}' 2>/dev/null)
+		[ -n "$client" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "inner client did not attach"
+}
+
+wait_for_option()
+{
+	option=$1
+	expected=$2
+	i=0
+	while [ "$i" -lt 50 ]; do
+		actual=$($INNER show-option -gv "$option" 2>/dev/null)
+		[ "$actual" = "$expected" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "$option is '$actual', expected '$expected'"
+}
+
+cleanup
+$INNER new-session -d -s inner -x40 -y10 'exec sleep 100' || exit 1
+$INNER set-option -g status off || exit 1
+$INNER set-option -g focus-events on || exit 1
+$OUTER new-session -d -s outer -x40 -y10 "$INNER attach -t inner" || exit 1
+$OUTER set-option -g status off || exit 1
+wait_for_client
+
+# The binding generated by send-keys -K must run before the command which
+# follows send-keys in this command list. Before the queue-ordering fix this
+# produces AB rather than BA.
+$INNER set-option -g @order '' || exit 1
+$INNER bind-key -n a set-option -gF @order '#{@order}B' || exit 1
+$INNER send-keys -K -c "$client" a \; \
+	set-option -gF @order '#{@order}A' || exit 1
+wait_for_option @order BA
+
+# Put the real attached client in the prefix table, deliver FocusIn, then the
+# bound key. FocusIn is not bindable and must not reset the prefix table.
+$INNER bind-key x set-option -g @focus-prefix yes || exit 1
+$OUTER send-keys C-b || exit 1
+focus_in=$(printf '\033[I')
+$OUTER send-keys -l "$focus_in" || exit 1
+$OUTER send-keys x || exit 1
+wait_for_option @focus-prefix yes
+
+exit 0

regress/clock-mode.sh

@@ -0,0 +1,101 @@
+#!/bin/sh
+
+# Exercise clock-mode initialization, all four styles, its one-second timer,
+# resize into the compact renderer, arbitrary-key exit, and cleanup.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+DIR=$(mktemp -d) || exit 1
+TMUX_TMPDIR=$DIR
+export TMUX_TMPDIR
+INNER="$TEST_TMUX -LtestI$$ -f/dev/null"
+OUTER="$TEST_TMUX -LtestO$$ -f/dev/null"
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$OUTER kill-server 2>/dev/null
+	$INNER kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+capture()
+{
+	$OUTER capture-pane -p -t outer:0.0 2>/dev/null
+}
+
+wait_mode()
+{
+	want=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		got=$($INNER display-message -p -t clock:0 '#{pane_mode}' 2>/dev/null)
+		[ "$got" = "$want" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "pane mode is '$got', expected '$want'"
+}
+
+wait_hashes()
+{
+	i=0
+	while [ "$i" -lt 50 ]; do
+		captured=$(capture)
+		printf '%s\n' "$captured" | grep -q '#' && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "large clock did not render"
+}
+
+$INNER new-session -d -s clock -x80 -y24 'exec sleep 100' || exit 1
+$INNER set-option -g status off || exit 1
+$INNER set-option -g window-size manual || exit 1
+$INNER set-option -w clock-mode-colour red || exit 1
+$OUTER new-session -d -s outer -x80 -y24 "$INNER attach -t clock" || exit 1
+$OUTER set-option -g status off || exit 1
+$OUTER set-option -g window-size manual || exit 1
+sleep 1
+
+for style in 12 24 12-with-seconds 24-with-seconds; do
+	$INNER set-option -w -t clock:0 clock-mode-style "$style" || exit 1
+	$INNER clock-mode -t clock:0 || exit 1
+	wait_mode clock-mode
+	wait_hashes
+	# Let at least one timer callback observe a new second.
+	[ "$style" != 12-with-seconds ] || sleep 1.2
+	$INNER send-keys -t clock:0 x || exit 1
+	wait_mode ''
+done
+
+# Resizing an active mode below the large-glyph threshold selects the compact
+# renderer. A visible time contains a colon and no block-clock hash.
+$INNER clock-mode -t clock:0 || exit 1
+wait_mode clock-mode
+$INNER resize-window -t clock:0 -x20 -y5 || exit 1
+i=0
+while [ "$i" -lt 50 ]; do
+	captured=$(capture)
+	printf '%s\n' "$captured" | grep -Eq '[0-9][0-9]?:[0-9][0-9]' && break
+	sleep 0.1
+	i=$((i + 1))
+done
+[ "$i" -lt 50 ] || fail "compact clock did not render after resize"
+printf '%s\n' "$captured" | grep -q '#' &&
+	fail "compact clock still used large glyphs"
+$INNER send-keys -t clock:0 Enter || exit 1
+wait_mode ''
+
+$INNER has-session -t clock || fail "server died during clock-mode tests"
+exit 0

regress/confirm-before-lock.sh

@@ -0,0 +1,150 @@
+#!/bin/sh
+
+# Exercise confirm-before's waiting and background callbacks, custom keys and
+# prompts, default-yes handling and errors. Also cover all three lock command
+# entry points with a harmless lock-command which leaves a marker.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+DIR=$(mktemp -d) || exit 1
+TMUX_TMPDIR=$DIR
+export TMUX_TMPDIR
+INNER="$TEST_TMUX -LtestI$$ -f/dev/null"
+OUTER="$TEST_TMUX -LtestO$$ -f/dev/null"
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$OUTER kill-server 2>/dev/null
+	$INNER kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+capture()
+{
+	$OUTER capture-pane -p -t outer:0.0 2>/dev/null
+}
+
+wait_capture()
+{
+	marker=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		captured=$(capture)
+		printf '%s\n' "$captured" | grep -Fq "$marker" && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "timed out waiting for '$marker'"
+}
+
+wait_option()
+{
+	want=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		got=$($INNER show-option -gqv @confirmed 2>/dev/null)
+		[ "$got" = "$want" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "@confirmed is '$got', expected '$want'"
+}
+
+wait_file()
+{
+	marker=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		[ -f "$marker" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "lock command did not create $marker"
+}
+
+$INNER new-session -d -s test -x80 -y24 'exec sleep 100' || exit 1
+$INNER set-option -g status on || exit 1
+$INNER set-option -g status-position bottom || exit 1
+$INNER set-option -g window-size manual || exit 1
+$OUTER new-session -d -s outer -x80 -y24 "$INNER attach -t test" || exit 1
+$OUTER set-option -g status off || exit 1
+$OUTER set-option -g window-size manual || exit 1
+sleep 1
+
+client=$($INNER list-clients -F '#{client_name}')
+[ -n "$client" ] || fail "inner client did not attach"
+
+$INNER bind-key -n M-a confirm-before \
+	'set-option -g @confirmed accepted' || exit 1
+$INNER bind-key -n M-b confirm-before -b -p 'Background?' \
+	'set-option -g @confirmed background' || exit 1
+$INNER bind-key -n M-c confirm-before -c x -p 'Custom?' \
+	'set-option -g @confirmed custom' || exit 1
+$INNER bind-key -n M-y confirm-before -y -p 'Default?' \
+	'set-option -g @confirmed default' || exit 1
+
+# A non-confirming response closes the waiting prompt without running its
+# command; reopening and accepting inserts the command after the waiting item.
+$INNER set-option -g @confirmed sentinel || exit 1
+$OUTER send-keys M-a || exit 1
+wait_capture "Confirm 'set-option'? (y/n)"
+$OUTER send-keys n || exit 1
+sleep 0.2
+wait_option sentinel
+$OUTER send-keys M-a || exit 1
+wait_capture "Confirm 'set-option'? (y/n)"
+$OUTER send-keys y || exit 1
+wait_option accepted
+
+# -b has no waiting queue item and appends its command to the client queue.
+$OUTER send-keys M-b || exit 1
+wait_capture 'Background?'
+$OUTER send-keys y || exit 1
+wait_option background
+
+# A custom printable key is accepted, and -y makes Enter affirmative.
+$OUTER send-keys M-c || exit 1
+wait_capture 'Custom?'
+$OUTER send-keys x || exit 1
+wait_option custom
+$OUTER send-keys M-y || exit 1
+wait_capture 'Default?'
+$OUTER send-keys Enter || exit 1
+wait_option default
+
+# Reject invalid multi-character and control confirmation keys.
+if $INNER confirm-before -b -t "$client" -c xx 'display-message x' \
+    >/dev/null 2>&1; then
+	fail "multi-character confirm key was accepted"
+fi
+if $INNER confirm-before -b -t "$client" -c "$(printf '\001')" \
+    'display-message x' >/dev/null 2>&1; then
+	fail "control confirm key was accepted"
+fi
+
+# lock-client, lock-session and lock-server all send lock-command to the real
+# attached client. The command returns immediately and unlocks the client.
+for kind in client session server; do
+	marker="$DIR/locked-$kind"
+	$INNER set-option -t test lock-command "printf locked >$marker" || exit 1
+	case "$kind" in
+	client) $INNER lock-client -t "$client" || exit 1 ;;
+	session) $INNER lock-session -t test || exit 1 ;;
+	server) $INNER lock-server || exit 1 ;;
+	esac
+	wait_file "$marker"
+done
+
+$INNER has-session -t test || fail "server died during prompt or lock tests"
+exit 0

regress/control-client-new-layouts.sh

@@ -0,0 +1,123 @@
+#!/bin/sh
+
+# Check that control client flags are available in every format expansion path
+# used to produce layouts. The layout strings themselves are tested separately.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+LANG=C.UTF-8
+export PATH TERM LC_ALL LANG
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+TMUX="$TEST_TMUX -LtestA$$ -f/dev/null"
+
+DIR=$(mktemp -d) || exit 1
+FIFO=$DIR/input
+OUT=$DIR/output
+CFG=$DIR/flags.conf
+PID=
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	exec 3>&-
+	[ -n "$PID" ] && kill "$PID" 2>/dev/null
+	$TMUX kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup EXIT
+
+wait_for()
+{
+	pattern=$1
+	i=0
+
+	while [ "$i" -lt 50 ]; do
+		grep -F -- "$pattern" "$OUT" >/dev/null 2>&1 && return 0
+		if [ -n "$PID" ] && ! kill -0 "$PID" 2>/dev/null; then
+			fail "control client exited waiting for: $pattern"
+		fi
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "missing: $pattern"
+}
+
+send()
+{
+	printf '%s\n' "$*" >&3
+}
+
+check_commands()
+{
+	name=$1
+	expected=$2
+	match='#{m:*new-layouts*,#{client_flags}}'
+
+	send "display-message -p 'DISPLAY-$name $match'"
+	wait_for "DISPLAY-$name $expected"
+	send "list-panes -F 'PANES-$name $match'"
+	wait_for "PANES-$name $expected"
+	send "list-windows -F 'WINDOWS-$name $match'"
+	wait_for "WINDOWS-$name $expected"
+	send "list-sessions -F 'SESSIONS-$name $match'"
+	wait_for "SESSIONS-$name $expected"
+	send "list-clients -F 'CLIENTS-$name $match'"
+	wait_for "CLIENTS-$name $expected"
+}
+
+check_config()
+{
+	name=$1
+	expected=$2
+
+	send "source-file '$CFG'"
+	send "display-message -p 'CONFIG-$name #{@config-new-layouts}'"
+	wait_for "CONFIG-$name $expected"
+}
+
+cat >"$CFG" <<'EOF'
+%if #{m:*new-layouts*,#{client_flags}}
+set-option -g @config-new-layouts 1
+%else
+set-option -g @config-new-layouts 0
+%endif
+EOF
+
+$TMUX kill-server 2>/dev/null
+$TMUX new-session -d -s layouts -x 80 -y 24 || exit 1
+$TMUX split-window -h -t layouts: || exit 1
+
+mkfifo "$FIFO" || exit 1
+: >"$OUT"
+$TMUX -C attach-session -t layouts <"$FIFO" >"$OUT" 2>&1 &
+PID=$!
+exec 3>"$FIFO"
+
+send 'display-message -p READY'
+wait_for READY
+
+check_commands OFF 0
+check_config OFF 0
+
+send 'refresh-client -f new-layouts'
+check_commands ON 1
+check_config ON 1
+
+send 'refresh-client -f !new-layouts'
+check_commands OFF-AGAIN 0
+check_config OFF-AGAIN 0
+
+# The list commands also run for unattached command clients. Supplying that
+# client to formats must not make the session loop dereference a NULL session.
+$TMUX list-sessions -F '#{S:all,active}' >/dev/null ||
+	fail "session loop failed for unattached command client"
+$TMUX has-session -t layouts || fail "server exited"
+
+exit 0

regress/control-client-popup.sh

@@ -0,0 +1,63 @@
+#!/bin/sh
+
+# Popups require a tty overlay and cannot be displayed by a control client.
+# A popup command from control mode must be ignored cleanly, leaving the
+# client command queue and server usable.
+
+PATH=/bin:/usr/bin
+TERM=screen
+export PATH TERM
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+TMUX="$TEST_TMUX -LtestA$$ -f/dev/null"
+DIR=$(mktemp -d) || exit 1
+FIFO=$DIR/input
+OUT=$DIR/output
+RAN=$DIR/popup-ran
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	exec 3>&-
+	$TMUX kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+mkfifo "$FIFO" || exit 1
+$TMUX new-session -d -s control -x40 -y10 'exec sleep 100' || exit 1
+$TMUX -C attach-session -t control <"$FIFO" >"$OUT" 2>&1 &
+control_pid=$!
+exec 3>"$FIFO"
+
+i=0
+while [ "$i" -lt 50 ]; do
+	$TMUX list-clients -F '#{client_flags}' 2>/dev/null |
+	    grep -q 'control-mode' && break
+	sleep 0.1
+	i=$((i + 1))
+done
+[ "$i" -lt 50 ] || fail "control client did not attach"
+
+printf '%s\n' "display-popup -E 'touch $RAN'" >&3
+printf '%s\n' "display-message -p CONTROL-POPUP-ALIVE" >&3
+
+i=0
+while [ "$i" -lt 50 ]; do
+	grep -q 'CONTROL-POPUP-ALIVE' "$OUT" 2>/dev/null && break
+	if ! kill -0 "$control_pid" 2>/dev/null; then
+		fail "control client exited after display-popup"
+	fi
+	sleep 0.1
+	i=$((i + 1))
+done
+[ "$i" -lt 50 ] || fail "command after control-client popup did not run"
+$TMUX has-session -t control || fail "server exited after control-client popup"
+[ ! -e "$RAN" ] || fail "control client started a popup command"
+
+exit 0

regress/control-client-run-shell-exit.sh

@@ -0,0 +1,38 @@
+#!/bin/sh
+
+# A waited run-shell command can complete after a control client has closed its
+# input and exited. The command queue still references the client until the job
+# callback runs, but control_stop has already destroyed c->control_state. Late
+# command output must be discarded instead of dereferencing the stopped control
+# state and killing the server.
+
+PATH=/bin:/usr/bin
+TERM=screen
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+TMUX="$TEST_TMUX -Ltest"
+$TMUX kill-server 2>/dev/null
+
+OUT=$(mktemp)
+trap "$TMUX kill-server 2>/dev/null; rm -f $OUT" 0 1 15
+
+$TMUX -f/dev/null new-session -d -s main || exit 1
+
+printf '%s\n' 'run-shell "sleep 0.2; echo TEST"' |
+	$TMUX -f/dev/null -C >"$OUT" 2>&1
+
+sleep 1
+
+$TMUX has-session -t main 2>/dev/null || {
+	echo "server exited after late run-shell output"
+	cat "$OUT"
+	exit 1
+}
+
+grep -q '^%exit' "$OUT" || {
+	echo "control client did not exit"
+	cat "$OUT"
+	exit 1
+}
+
+exit 0

regress/copy-mode-commands.sh

@@ -0,0 +1,253 @@
+#!/bin/sh
+
+# Exercise the broad non-mouse copy-mode command surface: navigation, search,
+# jumps, state toggles, line/end-of-line copies, append, and pipe variants.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+DIR=$(mktemp -d) || exit 1
+TMUX_TMPDIR=$DIR
+export TMUX_TMPDIR
+TMUX="$TEST_TMUX -Ltest$$ -f/dev/null"
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$TMUX kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+x()
+{
+	$TMUX send-keys -t copy:0 -X "$@" || fail "copy command failed: $*"
+}
+
+wait_mode()
+{
+	want=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		got=$($TMUX display-message -p -t copy:0 '#{pane_in_mode}' 2>/dev/null)
+		[ "$got" = "$want" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "pane_in_mode is '$got', expected '$want'"
+}
+
+fresh()
+{
+	$TMUX copy-mode -t copy:0 || exit 1
+	wait_mode 1
+	x history-top
+	x start-of-line
+}
+
+select_text()
+{
+	fresh
+	x begin-selection
+	x cursor-right
+	x cursor-right
+}
+
+$TMUX new-session -d -s copy -x40 -y8 \
+    "sh -c 'i=0; while [ \$i -lt 40 ]; do printf \"  line-%02d needle (a[b]c) end\\n\" \$i; i=\$((i + 1)); done; printf \"\\nparagraph two needle\\n\\nparagraph three\\n\"; printf \"\\033]133;A\\007prompt-one\\n\\033]133;C\\007output-one\\n\\033]133;A\\007prompt-two\\n\\033]133;C\\007output-two\\n\"; exec sleep 100'" ||
+	exit 1
+$TMUX set-option -g status off || exit 1
+$TMUX set-option -g history-limit 200 || exit 1
+
+i=0
+while [ "$i" -lt 50 ]; do
+	history=$($TMUX display-message -p -t copy:0 '#{history_size}')
+	[ "$history" -ge 30 ] && break
+	sleep 0.1
+	i=$((i + 1))
+done
+[ "$i" -lt 50 ] || fail "history did not fill"
+
+fresh
+
+# Copy-mode-specific format callbacks expose the word, line, hyperlink and
+# active search match at the cursor.
+formats=$($TMUX display-message -p -t copy:0 \
+    '#{copy_cursor_word}|#{copy_cursor_line}|#{copy_cursor_hyperlink}|#{search_match}') ||
+	exit 1
+[ -n "$formats" ] || fail "copy-mode cursor formats were empty"
+
+# Cursor, viewport and paragraph commands. Each is asserted by successful
+# dispatch and the final mode-liveness check; detailed word/selection geometry
+# is covered by the existing copy-mode tests.
+for command in back-to-indentation bottom-line top-line middle-line \
+    cursor-centre-vertical cursor-centre-horizontal end-of-line history-bottom \
+    history-top halfpage-down halfpage-up page-down page-up next-paragraph \
+    previous-paragraph next-matching-bracket previous-matching-bracket; do
+	x "$command"
+done
+x goto-line 15
+x set-mark
+x cursor-down
+x jump-to-mark
+
+# OSC 133 prompt and output markers support shell-integration navigation.
+x history-top
+x next-prompt
+case "$($TMUX display-message -p -t copy:0 '#{copy_cursor_line}')" in
+*prompt-one*) ;;
+*) fail "next-prompt did not find prompt-one" ;;
+esac
+x next-prompt
+x previous-prompt
+case "$($TMUX display-message -p -t copy:0 '#{copy_cursor_line}')" in
+*prompt-one*) ;;
+*) fail "previous-prompt did not return to prompt-one" ;;
+esac
+x next-prompt -o
+case "$($TMUX display-message -p -t copy:0 '#{copy_cursor_line}')" in
+*output-one*) ;;
+*) fail "next-prompt -o did not find output-one" ;;
+esac
+
+# Character jumps remember their direction and character for repeat/reverse.
+x jump-forward e
+x jump-again
+x jump-reverse
+x jump-backward e
+x jump-to-forward e
+x jump-to-backward e
+
+# Direct, text and incremental searches cover both directions and the saved
+# search used by again/reverse.
+x search-forward needle
+x search-again
+x search-reverse
+x search-backward needle
+x search-forward-text needle
+x search-backward-text needle
+x search-forward-incremental '=needle'
+x search-forward-incremental '+needle'
+x search-backward-incremental '=needle'
+x search-backward-incremental '-needle'
+
+# Stateful display and behaviour toggles.
+for command in rectangle-on rectangle-off rectangle-toggle \
+    line-numbers-on line-numbers-off line-numbers-toggle \
+    refresh-on refresh-now refresh-off refresh-toggle \
+    scroll-exit-on scroll-exit-off scroll-exit-toggle toggle-position; do
+	x "$command"
+done
+wait_mode 1
+x cancel
+wait_mode 0
+
+# Line and end-of-line copy commands work without an explicit selection.
+fresh
+x select-line
+x copy-selection-and-cancel
+case "$($TMUX show-buffer)" in
+*line-00*) ;;
+*) fail "select-line did not select the current line" ;;
+esac
+
+fresh
+x copy-line
+[ -n "$($TMUX show-buffer)" ] || fail "copy-line produced an empty buffer"
+x cancel
+
+fresh
+x copy-end-of-line
+[ -n "$($TMUX show-buffer)" ] || fail "copy-end-of-line produced an empty buffer"
+x cancel
+
+# Append variants retain or close the mode as advertised.
+$TMUX set-buffer -b append-buffer prefix || exit 1
+select_text
+x append-selection
+appended=$($TMUX show-buffer -b append-buffer)
+case "$appended" in
+prefix*) ;;
+*) fail "append-selection produced '$appended'" ;;
+esac
+x cancel
+
+$TMUX set-buffer -b append-cancel-buffer prefix || exit 1
+select_text
+x append-selection-and-cancel
+wait_mode 0
+appended=$($TMUX show-buffer -b append-cancel-buffer)
+case "$appended" in
+prefix*) ;;
+*) fail "append-selection-and-cancel produced '$appended'" ;;
+esac
+
+# The explicit cancel variants close copy mode.
+fresh
+x copy-line-and-cancel
+wait_mode 0
+fresh
+x copy-end-of-line-and-cancel
+wait_mode 0
+select_text
+x copy-selection-and-cancel
+wait_mode 0
+
+# Pipe wrappers have distinct command handlers. /dev/null keeps the test
+# deterministic while exercising asynchronous pipe job creation and cleanup.
+fresh
+x copy-pipe-line 'cat >/dev/null'
+x cancel
+fresh
+x copy-pipe-line-and-cancel 'cat >/dev/null'
+wait_mode 0
+fresh
+x copy-pipe-end-of-line 'cat >/dev/null'
+x cancel
+fresh
+x copy-pipe-end-of-line-and-cancel 'cat >/dev/null'
+wait_mode 0
+
+select_text
+x copy-pipe-no-clear 'cat >/dev/null'
+x pipe-no-clear 'cat >/dev/null'
+x copy-pipe 'cat >/dev/null'
+x pipe 'cat >/dev/null'
+x cancel
+select_text
+x copy-pipe-and-cancel 'cat >/dev/null'
+wait_mode 0
+select_text
+x pipe-and-cancel 'cat >/dev/null'
+wait_mode 0
+
+# Commands which cancel on downward movement have separate handlers.
+fresh
+x history-bottom
+x bottom-line
+x cursor-down-and-cancel
+wait_mode 0
+fresh
+x history-bottom
+x halfpage-down-and-cancel
+wait_mode 0
+fresh
+x history-bottom
+x page-down-and-cancel
+wait_mode 0
+fresh
+x history-bottom
+x bottom-line
+x scroll-down-and-cancel
+wait_mode 0
+
+$TMUX has-session -t copy || fail "server died during copy-mode commands"
+exit 0

regress/copy-mode-selection-mode.sh

@@ -0,0 +1,81 @@
+#!/bin/sh
+
+# Changing an existing character selection to line mode must reset both ends
+# to complete lines, including when the cursor subsequently crosses the fixed
+# end. An invalid regular-expression search must also discard marks left by a
+# previous successful search.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+TMUX="$TEST_TMUX -LtestA$$ -f/dev/null"
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$TMUX kill-server 2>/dev/null
+}
+trap cleanup 0 1 15
+
+$TMUX new-session -d -x30 -y6 \
+	"printf 'alpha\nbeta\ngamma\ndelta\n'; exec sleep 100" || exit 1
+$TMUX set-option -g window-size manual || exit 1
+sleep 1
+
+# A valid regular-expression search creates marks. Replacing it with an
+# invalid expression, growing the mode, and scrolling must not leave an old
+# mark array indexed with the new geometry (the original bug was an ASan heap
+# overflow in this sequence).
+$TMUX copy-mode || exit 1
+$TMUX send-keys -X history-top || exit 1
+$TMUX send-keys -X search-forward beta || exit 1
+[ "$($TMUX display-message -p '#{search_present}')" = 1 ] ||
+	fail "successful search did not create marks"
+$TMUX send-keys -X search-forward '[' || exit 1
+$TMUX resize-window -x40 -y8 || exit 1
+$TMUX send-keys -X scroll-down || exit 1
+[ "$($TMUX display-message -p '#{search_present}')" = 0 ] ||
+	fail "invalid regular expression left stale marks after resize"
+$TMUX send-keys -X cancel || exit 1
+
+# Select part of alpha through part of beta, then change the existing
+# selection to line mode. Both lines, and no partial columns, must be copied.
+$TMUX copy-mode || exit 1
+$TMUX send-keys -X history-top || exit 1
+$TMUX send-keys -N2 -X cursor-right || exit 1
+$TMUX send-keys -X begin-selection || exit 1
+$TMUX send-keys -X cursor-down || exit 1
+$TMUX send-keys -N2 -X cursor-right || exit 1
+$TMUX send-keys -X selection-mode line || exit 1
+[ "$($TMUX display-message -p '#{selection_mode}')" = line ] ||
+	fail "selection did not change to line mode"
+$TMUX send-keys -X copy-selection || exit 1
+expected=$(printf 'alpha\nbeta')
+[ "$($TMUX show-buffer)" = "$expected" ] ||
+	fail "line-mode selection did not expand to complete lines"
+
+# Start with the cursor above the fixed end so selection-mode itself takes the
+# reverse-direction path, then extend it through another line.
+$TMUX copy-mode || exit 1
+$TMUX send-keys -X history-top || exit 1
+$TMUX send-keys -N2 -X cursor-down || exit 1
+$TMUX send-keys -N2 -X cursor-right || exit 1
+$TMUX send-keys -X begin-selection || exit 1
+$TMUX send-keys -X cursor-up || exit 1
+$TMUX send-keys -N2 -X cursor-right || exit 1
+$TMUX send-keys -X selection-mode line || exit 1
+$TMUX send-keys -X cursor-up || exit 1
+$TMUX send-keys -X copy-selection || exit 1
+expected=$(printf 'alpha\nbeta\ngamma')
+[ "$($TMUX show-buffer)" = "$expected" ] ||
+	fail "reversed line-mode selection did not keep complete lines"
+
+exit 0

regress/copy-mode-unicode-whitespace.sh

@@ -0,0 +1,163 @@
+#!/bin/sh
+
+PATH=/bin:/usr/bin
+TERM=screen
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+
+fail()
+{
+	echo "$1"
+	[ -z "$TMUX" ] || $TMUX kill-server 2>/dev/null
+	exit 1
+}
+
+goto_cell()
+{
+	row=$1
+	column=$2
+
+	$TMUX send-keys -X history-top || fail "$mode: history-top failed"
+	$TMUX send-keys -X start-of-line || fail "$mode: start-of-line failed"
+	[ "$row" -eq 0 ] ||
+	    $TMUX send-keys -X -N "$row" cursor-down ||
+	    fail "$mode: cursor-down failed"
+	[ "$column" -eq 0 ] ||
+	    $TMUX send-keys -X -N "$column" cursor-right ||
+	    fail "$mode: cursor-right failed"
+}
+
+check_cursor()
+{
+	expected=$1
+	actual=$($TMUX display-message -p '#{copy_cursor_x},#{copy_cursor_y}')
+	[ "$actual" = "$expected" ] ||
+	    fail "$mode: expected cursor $expected, got $actual"
+}
+
+check_word()
+{
+	row=$1
+	column=$2
+	expected=$3
+
+	goto_cell "$row" "$column"
+	$TMUX set-buffer sentinel || fail "$mode: set-buffer failed"
+	$TMUX send-keys -X select-word || fail "$mode: select-word failed"
+	$TMUX send-keys -X copy-selection || fail "$mode: copy-selection failed"
+	actual=$($TMUX show-buffer 2>/dev/null)
+	[ "$actual" = "$expected" ] ||
+	    fail "$mode: expected word '$expected', got '$actual'"
+}
+
+check_next_word()
+{
+	row=$1
+	expected=$2
+
+	goto_cell "$row" 0
+	$TMUX send-keys -X next-word || fail "$mode: next-word failed"
+	$TMUX set-buffer sentinel || fail "$mode: set-buffer failed"
+	$TMUX send-keys -X select-word || fail "$mode: select-word failed"
+	$TMUX send-keys -X copy-selection || fail "$mode: copy-selection failed"
+	actual=$($TMUX show-buffer 2>/dev/null)
+	[ "$actual" = "$expected" ] ||
+	    fail "$mode: expected next word '$expected', got '$actual'"
+}
+
+for mode in emacs vi; do
+	TMUX="$TEST_TMUX -Lunicode-whitespace-$mode-$$ -f/dev/null"
+	$TMUX kill-server 2>/dev/null
+	$TMUX new-session -d -x16 -y20 \
+	    "printf 'aa bb\naa\tbb\naa\302\240bb\naa\343\200\200bb\naa:bb\naaaaaaaaaaaaaaa\302\240b\nabcdefghijklmnopq\nhardone\nhardtwo\naa\341\232\200bb\naa\342\200\200bb\naa\342\200\250bb\naa\342\200\251bb\naa\342\200\257bb\naa\342\201\237bb\nxa\302\205b c\n'; exec cat" ||
+	    fail "$mode: new-session failed"
+	$TMUX set-option -g window-size manual || fail "$mode: set size failed"
+	$TMUX set-window-option -g mode-keys "$mode" ||
+	    fail "$mode: set mode-keys failed"
+	$TMUX set-window-option -g word-separators "" ||
+	    fail "$mode: clear word-separators failed"
+	$TMUX copy-mode || fail "$mode: copy-mode failed"
+
+	# ASCII space and TAB retain their existing behaviour.
+	goto_cell 0 0
+	$TMUX send-keys -X next-space || fail "$mode: ASCII next-space failed"
+	check_cursor 3,0
+	goto_cell 1 0
+	$TMUX send-keys -X next-space || fail "$mode: TAB next-space failed"
+	check_cursor 8,1
+	$TMUX send-keys -X previous-space ||
+	    fail "$mode: TAB previous-space failed"
+	check_cursor 0,1
+
+	# NBSP is whitespace for selection and word movement.
+	goto_cell 2 0
+	$TMUX send-keys -X next-word || fail "$mode: NBSP next-word failed"
+	check_cursor 3,2
+	$TMUX send-keys -X previous-word ||
+	    fail "$mode: NBSP previous-word failed"
+	check_cursor 0,2
+	check_word 2 0 aa
+	goto_cell 2 0
+	$TMUX send-keys -X next-word-end ||
+	    fail "$mode: NBSP next-word-end failed"
+	if [ "$mode" = emacs ]; then
+		check_cursor 2,2
+	else
+		check_cursor 1,2
+	fi
+
+	# U+3000 is two columns wide; both its leading and padding cells must be
+	# skipped as one whitespace character in either direction.
+	goto_cell 3 0
+	$TMUX send-keys -X next-word || fail "$mode: U+3000 next-word failed"
+	check_cursor 4,3
+	$TMUX send-keys -X previous-word ||
+	    fail "$mode: U+3000 previous-word failed"
+	check_cursor 0,3
+	goto_cell 3 0
+	$TMUX send-keys -X next-space-end ||
+	    fail "$mode: U+3000 next-space-end failed"
+	if [ "$mode" = emacs ]; then
+		check_cursor 2,3
+	else
+		check_cursor 1,3
+	fi
+
+	# Other characters in word-separators remain literal when space enables
+	# Unicode whitespace matching.
+	$TMUX set-window-option -g word-separators ': ' ||
+	    fail "$mode: set custom word-separators failed"
+	goto_cell 4 0
+	$TMUX send-keys -X next-word || fail "$mode: literal next-word failed"
+	check_cursor 2,4
+	$TMUX set-window-option -g word-separators "" ||
+	    fail "$mode: restore word-separators failed"
+
+	# Whitespace in the last column remains a boundary across a soft wrap.
+	goto_cell 5 0
+	$TMUX send-keys -X next-space ||
+	    fail "$mode: wrapped NBSP next-space failed"
+	check_cursor 0,6
+
+	# A word split only by a soft wrap remains one word, while a hard line
+	# boundary still terminates selection.
+	check_word 7 0 abcdefghijklmnopq
+	check_word 9 0 hardone
+
+	# Check the remaining representative White_Space ranges and U+0085
+	# combined into a cell with another character.
+	check_next_word 11 bb
+	check_next_word 12 bb
+	check_next_word 13 bb
+	check_next_word 14 bb
+	check_next_word 15 bb
+	check_next_word 16 bb
+	goto_cell 17 0
+	$TMUX send-keys -X next-word ||
+	    fail "$mode: combined U+0085 next-word failed"
+	check_cursor 2,17
+
+	$TMUX kill-server 2>/dev/null
+done
+
+exit 0

regress/find-window.sh

@@ -0,0 +1,118 @@
+#!/bin/sh
+
+# Exercise find-window's content, name and title filters in every combination,
+# glob/regex and case-insensitive suffixes, plus zoom restoration.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+DIR=$(mktemp -d) || exit 1
+TMUX_TMPDIR=$DIR
+export TMUX_TMPDIR
+INNER="$TEST_TMUX -LtestI$$ -f/dev/null"
+OUTER="$TEST_TMUX -LtestO$$ -f/dev/null"
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$OUTER kill-server 2>/dev/null
+	$INNER kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+capture()
+{
+	$OUTER capture-pane -p -t outer:0.0 2>/dev/null
+}
+
+wait_mode()
+{
+	want=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		got=$($INNER display-message -p -t find:base.0 '#{pane_mode}' 2>/dev/null)
+		[ "$got" = "$want" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "pane mode is '$got', expected '$want'"
+}
+
+run_find()
+{
+	label=$1
+	expected=$2
+	shift 2
+	$INNER find-window -t find:base.0 "$@" || fail "$label failed"
+	wait_mode tree-mode
+	i=0
+	while [ "$i" -lt 50 ]; do
+		captured=$(capture)
+		printf '%s\n' "$captured" | grep -Fq "$expected" && break
+		sleep 0.1
+		i=$((i + 1))
+	done
+	[ "$i" -lt 50 ] || fail "$label did not show '$expected'"
+	$INNER send-keys -t find:base.0 q || exit 1
+	wait_mode ''
+}
+
+$INNER new-session -d -s find -n base -x80 -y24 \
+	"sh -c 'printf \"BaseBody\\n\"; exec sleep 100'" || exit 1
+$INNER split-window -d -h -t find:base \
+	"sh -c 'printf \"OtherBody\\n\"; exec sleep 100'" || exit 1
+$INNER new-window -d -t find: -n NameNeedle 'exec sleep 100' || exit 1
+$INNER new-window -d -t find: -n body \
+	"sh -c 'printf \"BodyNeedle\\n\"; exec sleep 100'" || exit 1
+$INNER new-window -d -t find: -n titled 'exec sleep 100' || exit 1
+$INNER select-pane -t find:titled.0 -T TitleNeedle || exit 1
+$INNER set-option -g status off || exit 1
+$INNER set-option -g window-size manual || exit 1
+$OUTER new-session -d -s outer -x80 -y24 "$INNER attach -t find:base" || exit 1
+$OUTER set-option -g status off || exit 1
+$OUTER set-option -g window-size manual || exit 1
+sleep 1
+
+# Wait until the body text is in the pane history before searching it.
+i=0
+while [ "$i" -lt 50 ]; do
+	$INNER capture-pane -p -t find:body.0 | grep -Fq BodyNeedle && break
+	sleep 0.1
+	i=$((i + 1))
+done
+[ "$i" -lt 50 ] || fail "pane content was not ready"
+
+# No flags means C+N+T. Then cover all three pairs and all three singletons.
+run_find default NameNeedle NameNeedle
+run_find content-name NameNeedle -C -N NameNeedle
+run_find content-title titled -C -T TitleNeedle
+run_find name-title titled -N -T TitleNeedle
+run_find content-only body -C BodyNeedle
+run_find name-only NameNeedle -N NameNeedle
+run_find title-only titled -T TitleNeedle
+
+# Glob case folding and all regular-expression suffix variants.
+run_find insensitive NameNeedle -N -i nameneedle
+run_find regex NameNeedle -N -r '^NameNeedle$'
+run_find regex-insensitive NameNeedle -N -r -i '^nameneedle$'
+
+# -Z temporarily zooms the target window and restores its prior state on exit.
+$INNER find-window -Z -t find:base.0 -N NameNeedle || exit 1
+wait_mode tree-mode
+[ "$($INNER display-message -p -t find:base '#{window_zoomed_flag}')" = 1 ] ||
+	fail "find-window -Z did not zoom"
+$INNER send-keys -t find:base.0 q || exit 1
+wait_mode ''
+[ "$($INNER display-message -p -t find:base '#{window_zoomed_flag}')" = 0 ] ||
+	fail "find-window -Z did not restore zoom"
+
+exit 0

regress/floating-pane-geometry.sh

@@ -199,5 +199,74 @@ must_fail $TMUX resize-pane -t "$id" -x 0
 must_fail $TMUX resize-pane -t "$id" -y 0
 $TMUX kill-pane -t "$id" || exit 1
 
+# --- Tiled pane resize with floating cells in the layout ---
+
+$TMUX set-option -w -u pane-border-lines || exit 1
+base=$($TMUX display-message -p '#{pane_id}')
+
+# A floating cell after the last tiled cell must not become the recipient of a
+# relative or absolute resize. This is the sequence from GitHub issue 5135.
+floating=$($TMUX new-pane -dPF '#{pane_id}' -t "$base" \
+	-x 50% -y 50% -X 50% -Y 50% 'sleep 100') ||
+	fail "new-pane for tiled resize test failed"
+lower=$($TMUX split-window -dPF '#{pane_id}' -t "$base" 'sleep 100') ||
+	fail "split-window for tiled resize test failed"
+
+$TMUX resize-pane -t "$lower" -U 5 || fail "relative tiled resize failed"
+must_equal "$($TMUX display-message -p -t "$base" '#{pane_height}')" 7
+must_equal "$($TMUX display-message -p -t "$lower" '#{pane_top}')" 8
+must_equal "$($TMUX display-message -p -t "$lower" '#{pane_height}')" 16
+must_equal "$($TMUX display-message -p -t "$floating" '#{pane_top}')" 13
+must_equal "$($TMUX display-message -p -t "$floating" '#{pane_height}')" 10
+
+$TMUX resize-pane -t "$lower" -y 11 || fail "absolute tiled reset failed"
+$TMUX resize-pane -t "$lower" -y 16 || fail "absolute tiled resize failed"
+must_equal "$($TMUX display-message -p -t "$base" '#{pane_height}')" 7
+must_equal "$($TMUX display-message -p -t "$lower" '#{pane_top}')" 8
+must_equal "$($TMUX display-message -p -t "$lower" '#{pane_height}')" 16
+must_equal "$($TMUX display-message -p -t "$floating" '#{pane_height}')" 10
+
+$TMUX kill-pane -t "$floating" || exit 1
+$TMUX kill-pane -t "$lower" || exit 1
+
+# A floating cell between tiled siblings must be skipped when finding the cell
+# which donates space to a resize.
+lower=$($TMUX split-window -dPF '#{pane_id}' -t "$base" 'sleep 100') ||
+	fail "split-window for middle floating cell test failed"
+floating=$($TMUX new-pane -dPF '#{pane_id}' -t "$base" \
+	-x 20 -y 8 -X 30 -Y 8 'sleep 100') ||
+	fail "new-pane for middle floating cell test failed"
+
+$TMUX resize-pane -t "$base" -D 3 || fail "resize past floating cell failed"
+must_equal "$($TMUX display-message -p -t "$base" '#{pane_height}')" 15
+must_equal "$($TMUX display-message -p -t "$lower" '#{pane_top}')" 16
+must_equal "$($TMUX display-message -p -t "$lower" '#{pane_height}')" 8
+must_equal "$($TMUX display-message -p -t "$floating" '#{pane_height}')" 6
+
+$TMUX kill-pane -t "$floating" || exit 1
+$TMUX kill-pane -t "$lower" || exit 1
+
+# A small floating child must not limit the available tiled space in a nested
+# layout with a different split direction.
+lower=$($TMUX split-window -dPF '#{pane_id}' -t "$base" 'sleep 100') ||
+	fail "split-window for nested floating cell test failed"
+right=$($TMUX split-window -dhPF '#{pane_id}' -t "$lower" 'sleep 100') ||
+	fail "horizontal split for nested floating cell test failed"
+floating=$($TMUX new-pane -dPF '#{pane_id}' -t "$lower" \
+	-x 20 -y 3 -X 30 -Y 10 'sleep 100') ||
+	fail "new-pane for nested floating cell test failed"
+
+$TMUX resize-pane -t "$base" -D 3 || fail "nested tiled resize failed"
+must_equal "$($TMUX display-message -p -t "$base" '#{pane_height}')" 15
+must_equal "$($TMUX display-message -p -t "$lower" '#{pane_top}')" 16
+must_equal "$($TMUX display-message -p -t "$lower" '#{pane_height}')" 8
+must_equal "$($TMUX display-message -p -t "$right" '#{pane_top}')" 16
+must_equal "$($TMUX display-message -p -t "$right" '#{pane_height}')" 8
+must_equal "$($TMUX display-message -p -t "$floating" '#{pane_height}')" 1
+
+$TMUX kill-pane -t "$floating" || exit 1
+$TMUX kill-pane -t "$right" || exit 1
+$TMUX kill-pane -t "$lower" || exit 1
+
 $TMUX kill-server 2>/dev/null
 exit 0

regress/format-variables.sh

@@ -71,7 +71,10 @@ cursor_very_visible
 cursor_x
 cursor_y
 history_all_bytes
+history_added
 history_bytes
+history_collected
+history_generation
 history_limit
 history_size
 host
@@ -103,6 +106,11 @@ pane_at_right
 pane_at_top
 pane_bg
 pane_bottom
+pane_command_duration
+pane_command_end_time
+pane_command_running
+pane_command_start_time
+pane_command_status
 pane_current_command
 pane_current_path
 pane_dead
@@ -120,16 +128,21 @@ pane_index
 pane_input_off
 pane_key_mode
 pane_last
+pane_last_output_time
+pane_last_prompt_time
 pane_left
 pane_marked
 pane_marked_set
+pane_modal_flag
 pane_mode
+pane_output_generation
 pane_path
 pane_pb_progress
 pane_pb_state
 pane_pid
 pane_pipe
 pane_pipe_pid
+pane_private_modes
 pane_right
 pane_search_string
 pane_start_command
@@ -141,6 +154,8 @@ pane_title
 pane_top
 pane_tty
 pane_unseen_changes
+pane_unzoomed_height
+pane_unzoomed_width
 pane_width
 pane_x
 pane_y
@@ -206,7 +221,10 @@ window_layout
 window_linked
 window_linked_sessions
 window_linked_sessions_list
+window_manual_height
+window_manual_width
 window_marked_flag
+window_modal_pane
 window_name
 window_offset_x
 window_offset_y

regress/hooks-notify.sh

@@ -218,11 +218,13 @@ $TMUX set-hook -gu pane-mode-changed || fail "unset pane-mode-changed failed"
 
 # pane-exited when a pane's command exits with remain-on-exit off.
 $TMUX set -g @x 0 || fail "set @x failed"
-$TMUX set-hook -g pane-exited 'set -gF @x "#{hook}:#{hook_pane}"' ||
+$TMUX set-hook -g pane-exited \
+	'set -gF @x "#{hook}:#{hook_pane}:#{hook_exit_status}:#{hook_exit_success}"' ||
 	fail "set-hook pane-exited failed"
-pane=$($TMUX splitw -d -t main:0 -P -F '#{pane_id}' 'true') ||
-	fail "split-window true failed"
-wait_for @x "pane-exited:$pane"
+pane=$($TMUX splitw -d -t main:0 -P -F '#{pane_id}' \
+	'trap "" HUP; exec </dev/null >/dev/null 2>&1; sleep 1; exit 42') ||
+	fail "split-window exit 42 failed"
+wait_for @x "pane-exited:$pane:42:0"
 $TMUX set-hook -gu pane-exited || fail "unset pane-exited failed"
 
 # pane-died when a pane's command exits with remain-on-exit on.

regress/json.sh

@@ -0,0 +1,137 @@
+#!/bin/sh
+
+# Test parsing and printing JSON with display-message -j.
+
+PATH=/bin:/usr/bin
+TERM=screen
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+TMUX="$TEST_TMUX -LtestA$$ -f/dev/null"
+$TMUX kill-server 2>/dev/null
+
+fail()
+{
+	echo "$1"
+	$TMUX kill-server 2>/dev/null
+	exit 1
+}
+
+check()
+{
+	actual=$($TMUX display-message -plj "$1" 2>&1) ||
+	    fail "JSON was rejected: $1: $actual"
+	[ "$actual" = "$2" ] ||
+	    fail "JSON output mismatch: $1: expected $2, got $actual"
+}
+
+check_fail()
+{
+	if $TMUX display-message -plj "$1" >/dev/null 2>&1; then
+		fail "invalid JSON was accepted: $1"
+	fi
+}
+
+$TMUX new-session -d || exit 1
+
+check '{}' '{}'
+check ' { "z":true, "a":-9223372036854775808, "m":[{}, {"x":false}] } ' \
+    '{"a":-9223372036854775808,"m":[{},{"x":false}],"z":true}'
+check '{"max":9223372036854775807,"min":-9223372036854775808}' \
+    '{"max":9223372036854775807,"min":-9223372036854775808}'
+check '{" key":" value","{key":"[value"}' \
+    '{" key":" value","{key":"[value"}'
+check '{"brace":"{value","bracket":"[value","colon":":value",'\
+'"comma":",value","space":" value"}' \
+    '{"brace":"{value","bracket":"[value","colon":":value",'\
+'"comma":",value","space":" value"}'
+check '{"esc":"\"\\\/\b\f\n\r\t\u0041"}' \
+    '{"esc":"\"\\\/\b\f\n\r\t\u0041"}'
+check '{"unicode":"\u0123\uabcd\uABCD"}' \
+    '{"unicode":"\u0123\uabcd\uABCD"}'
+
+actual=$($TMUX display-message -palj '{}' 2>&1) ||
+    fail "display-message -aj rejected JSON: $actual"
+[ "$actual" = '{}' ] ||
+    fail "display-message -aj did not ignore -a: got $actual"
+actual=$($TMUX display-message -pIlj '{}' 2>&1) ||
+    fail "display-message -Ij rejected JSON: $actual"
+[ "$actual" = '{}' ] ||
+    fail "display-message -Ij did not ignore -I: got $actual"
+
+check_fail ''
+check_fail '   '
+check_fail '[]'
+check_fail 'true'
+check_fail '1'
+check_fail '"string"'
+check_fail '{}{}'
+
+check_fail '{'
+check_fail '{x:1}'
+check_fail '{"":1}'
+check_fail '{"x" 1}'
+check_fail '{"x",1}'
+check_fail '{"x":}'
+check_fail '{"x":,}'
+check_fail '{"x":1'
+check_fail '{"x":1 "y":2}'
+check_fail '{"x":1,,"y":2}'
+check_fail '{"x":1,}'
+check_fail '{"x":1,"x":2}'
+check_fail '{"x":{}}{}'
+check_fail '{"x":{}} trailing'
+check_fail '{"x":{'
+check_fail '{"x":{}'
+
+check_fail '{"x":['
+check_fail '{"x":[}'
+check_fail '{"x":[{}'
+check_fail '{"x":[{},}'
+check_fail '{"x":[{},]}'
+check_fail '{"x":[{}{}]}'
+check_fail '{"x":[{},,{}]}'
+check_fail '{"x":[{"y":}]}'
+check_fail '{"x":""}'
+check_fail '{"x":null}'
+check_fail '{"x":[null]}'
+check_fail '{"x":[true]}'
+check_fail '{"x":["string"]}'
+check_fail '{"x":[[]]}'
+check_fail '{"x":1.0}'
+check_fail '{"x":1e2}'
+check_fail '{"x":+1}'
+check_fail '{"x":-}'
+check_fail '{"x":0x10}'
+check_fail '{"x":01}'
+check_fail '{"x":-01}'
+check_fail '{"x":[1]}'
+check_fail '{"x":9223372036854775808}'
+check_fail '{"x":-9223372036854775809}'
+check_fail '{"x":tru}'
+check_fail '{"x":True}'
+check_fail '{"x":falsee}'
+check_fail '{"x":"bad\q"}'
+check_fail '{"x":"bad\x20"}'
+check_fail '{"x":"bad\u123"}'
+check_fail '{"x":"bad\u12x4"}'
+check_fail '{"x":"unterminated}'
+check_fail '{"x":"escaped quote\"}'
+check_fail '{"x":"line
+break"}'
+
+# The maximum object nesting depth is 200.
+json='{}'
+n=1
+while [ "$n" -lt 200 ]; do
+	json='{"x":'"$json"'}'
+	n=$((n + 1))
+done
+check "$json" "$json"
+check_fail '{"x":'"$json"'}'
+
+if $TMUX display-message -pj >/dev/null 2>&1; then
+	fail "display-message -j accepted a missing message"
+fi
+
+$TMUX kill-server 2>/dev/null
+exit 0

regress/layout-custom.sh

@@ -0,0 +1,986 @@
+#!/bin/sh
+
+# Tests of the custom layout dumper and evaluator in layout-custom.c, and of
+# the JSON tokenizer and parser in json.c that the current layout format is
+# built on.
+#
+# layout_dump is reached through the #{window_layout} and
+# #{window_visible_layout} formats and layout_parse through
+# "select-layout <layout>". json.c has no command of its own either:
+# layout_construct sniffs the first non-blank character and hands anything
+# starting with '{' to json_parse, so select-layout is the only way into it
+# from the shell as well.
+#
+# Both layout formats are covered:
+# - the current (v2) JSON format, which is what every client except an old
+#   control client sees;
+# - the legacy (v1) format, which is still produced for a control client that
+#   has not asked for the "new-layouts" flag, and which is still accepted by
+#   the parser (the version is sniffed from the first character).
+#
+# This exercises:
+# - dumping a single pane, a split, the "a" (active) and "l" (last pane) keys
+#   and the "z" key of a floating pane;
+# - #{window_visible_layout} agreeing with #{window_layout};
+# - the JSON syntax itself: insignificant whitespace, backslash escapes inside
+#   strings, the number and boolean forms, and one failure for each way json.c
+#   can reject an input that a layout string can carry;
+# - a dump being parsed back to exactly the same layout (round trip), after
+#   another layout has been applied in between, and the same for a layout with
+#   two floating panes in it;
+# - parsing a hand-written v2 layout;
+# - "i" deciding which pane goes in which cell, checked with a layout whose
+#   cells are written in a different order from their indexes;
+# - the same layouts with their fields in reversed and scrambled orders,
+#   including "c" before "t" and "V" after "L", neither of which changes the
+#   order the fields are read in;
+# - a layout with more cells than the window has panes having the bottom right
+#   cells dropped, in both formats;
+# - a layout naming no active or last pane leaving the active pane where it was
+#   and emptying the last pane stack, whether it leaves "a" out or gives it as
+#   false;
+# - parsing a v1 layout and dumping it back as v1 through a control client,
+#   with the checksum computed here independently of layout_checksum(), and a
+#   v1 layout leaving the active pane and last pane stack untouched;
+# - the legacy format meeting the floating panes it cannot represent: a v1 dump
+#   dropping the floating cells, both where that leaves the node they were in
+#   with one child so that it collapses, where it does not, and where adjacent
+#   nested floating-only subtrees are dropped, and a v1 layout being applied to
+#   a window that has floating panes without disturbing them, whether the tiled
+#   layout it names is a single cell or a split;
+# - a window whose only tiled pane has been killed, which leaves it with a
+#   floating cell as its layout root or with a root node holding nothing but
+#   floating cells, producing no v1 dump at all, and being parsed as v1;
+# - the %layout-change notification, in both formats at once: two control
+#   clients watching one layout change, only one of which has asked for new
+#   layouts, and the number of notifications a change produces in each format;
+# - failures: a bad v1 header, checksum or body, a wrong version, a missing or
+#   duplicated root cell, missing sizes, sizes out of range, bad cell types, a
+#   pane cell missing "i", leaf cells with children and node cells with fewer
+#   than two, more than one active pane, too few cells for the panes and
+#   inconsistent sizes.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LANG=C.UTF-8
+LC_ALL=C.UTF-8
+export TERM LANG LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+TMUX="$TEST_TMUX -LtestA$$ -f/dev/null"
+$TMUX kill-server 2>/dev/null
+
+fail()
+{
+	echo "$*" >&2
+	$TMUX kill-server 2>/dev/null
+	exit 1
+}
+
+# must_equal $what $got $expected
+must_equal()
+{
+	if [ "$2" != "$3" ]; then
+		echo "$1 wrong." >&2
+		echo "Expected: '$3'" >&2
+		echo "But got:  '$2'" >&2
+		$TMUX kill-server 2>/dev/null
+		exit 1
+	fi
+}
+
+# must_differ $what $got $unwanted
+must_differ()
+{
+	[ "$2" != "$3" ] || fail "$1 unchanged: '$2'"
+}
+
+# must_contain $what $got $wanted
+must_contain()
+{
+	case "$2" in
+	*"$3"*) ;;
+	*) fail "$1: '$2' does not contain '$3'";;
+	esac
+}
+
+# check_ok $cmd...
+#
+# Run a command and require that it succeeds.
+check_ok()
+{
+	out=$($TMUX "$@" 2>&1) || fail "Command failed (expected success): $* ($out)"
+}
+
+# check_fail $cmd...
+#
+# Run a command and require that it fails. The error text itself is never
+# checked anywhere in this test: the wording of a message is not part of what
+# the layout formats promise, so matching on it only makes the test fail when a
+# message is reworded.
+check_fail()
+{
+	$TMUX "$@" >/dev/null 2>&1 &&
+		fail "Command succeeded (expected failure): $*"
+}
+
+# layout $target
+#
+# The layout of a window with pane ids replaced by %N, so that the expected
+# strings do not depend on which ids the server handed out.
+layout()
+{
+	$TMUX display-message -p -t "$1" '#{window_layout}' |
+		sed 's/%[0-9][0-9]*/%N/g'
+}
+
+# visible_layout $target
+#
+# As layout(), but the visible (zoomed) layout.
+visible_layout()
+{
+	$TMUX display-message -p -t "$1" '#{window_visible_layout}' |
+		sed 's/%[0-9][0-9]*/%N/g'
+}
+
+# raw_layout $target
+#
+# The layout of a window with the real pane ids left in place.
+raw_layout()
+{
+	$TMUX display-message -p -t "$1" '#{window_layout}'
+}
+
+# v1_layout $target
+#
+# The legacy (v1) dump of a window, which is what a control client that has not
+# asked for the "new-layouts" flag is sent. A control client wraps its output in
+# %begin/%end guard lines, which are dropped here.
+v1_layout()
+{
+	$TMUX -C display-message -p -t "$1" '#{window_layout}' | grep -v '^%'
+}
+
+# v1 $body
+#
+# Prefix a legacy (v1) layout body with its checksum. This is a separate
+# implementation of layout_checksum(): a 16 bit rotate right then add, so a
+# mistake in either one shows up as a mismatch.
+v1()
+{
+	awk -v s="$1" 'BEGIN {
+		for (i = 32; i < 127; i++)
+			ord[sprintf("%c", i)] = i
+		csum = 0
+		for (i = 1; i <= length(s); i++) {
+			csum = int(csum / 2) + (csum % 2) * 32768
+			csum = (csum + ord[substr(s, i, 1)]) % 65536
+		}
+		printf "%04x,%s\n", csum, s
+	}'
+}
+
+# A pane cell is dumped as its geometry, then "a" if it is the active pane or
+# "l" with its position on the last pane stack if it is on it, then "i" with
+# its pane index, then "z" if it is floating, then "I" with its pane id.
+ONE='{"V":2,"L":{"t":"p","w":80,"h":24,"x":0,"y":0,"a":true,"i":0,"I":"%N"}}'
+
+check_ok new-session -d -s L -x 80 -y 24 -n one
+
+p0=$($TMUX display-message -p -t L:one.0 '#{pane_id}')
+
+# A single leaf cell filling the window. A pane cell must carry "i", its pane
+# index; "I", its pane id, is written by the dumper and is here so that the cell
+# is the same shape as a dumped one. The JSON checks below care about the syntax
+# around the cell rather than the cell itself.
+LEAF='{"t":"p","w":80,"h":24,"x":0,"y":0,"i":0,"I":"'"$p0"'"}'
+
+# ---------------------------------------------------------------------------
+# Dumping a single pane.
+
+# The root cell of a new window is the pane itself, and it is the active pane
+# so it has "a" rather than "l".
+must_equal 'Single pane layout' "$(layout L:one)" "$ONE"
+
+# Nothing is zoomed, so the visible layout is the same.
+must_equal 'Single pane visible layout' "$(visible_layout L:one)" "$ONE"
+
+# ---------------------------------------------------------------------------
+# More cells than panes.
+
+# The bottom right cells are closed until as many are left as there are panes,
+# so a two cell layout applied to a one pane window collapses back to the
+# single pane filling the window: the cell that is left takes the space of the
+# one that was closed. The window has one pane to name, so the cell that is
+# closed carries an id belonging to no pane of it.
+check_ok select-layout -t L:one \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":11,"x":0,"y":0,"i":0,"I":"'"$p0"'"},{"t":"p","w":80,"h":12,"x":0,"y":12,"i":1,"I":"%999"}]}}'
+must_equal 'Trimmed layout' "$(layout L:one)" "$ONE"
+
+# ---------------------------------------------------------------------------
+# The JSON syntax.
+#
+# These run on the one pane window and are written so that what they prove
+# depends on json.c rather than on the layout evaluation in layout-custom.c:
+# an accepted layout is only required to leave the window as its single pane,
+# and values that are not part of the layout format are carried on keys
+# layout-custom.c never looks at ("n", "b" and so on), which it skips, so
+# numbers, booleans and escapes can be exercised on their own.
+#
+# Objects nested in an array nested in an object are not checked here: every
+# split layout below is one.
+#
+# Two of json.c's rejections cannot be reached from the shell and so are not
+# covered: json_parse_tokens() refusing a top level that is not an object,
+# because layout_construct() only calls json_parse() once the string already
+# starts with '{'; and the maximum object depth, which needs a layout built by a
+# program rather than one written out here.
+
+# check_json_ok $what $layout
+#
+# select-layout must parse $layout and leave the window as its single pane.
+check_json_ok()
+{
+	check_ok select-layout -t L:one "$2"
+	must_equal "Layout after '$1'" "$(layout L:one)" "$ONE"
+}
+
+# check_json_fail $what $layout
+#
+# select-layout must reject $layout.
+check_json_fail()
+{
+	$TMUX select-layout -t L:one "$2" >/dev/null 2>&1 &&
+		fail "$1: select-layout succeeded (expected failure)"
+}
+
+# Whitespace between tokens is skipped. A number is scanned up to the ',', ']',
+# '}' or whitespace that ends it, so a space after a number is fine but one
+# inside it is not.
+check_json_ok 'Spaces between tokens' \
+	'{ "V" : 2 , "L" : { "t" : "p" , "w" : 80 , "h" : 24 , "x" : 0 , "y" : 0 , "i" : 0 , "I" : "'"$p0"'" } }'
+
+check_json_ok 'Newlines and tabs between tokens' "$(printf '{
+\t"V": 2,
+\t"L": {
+\t\t"t": "p",
+\t\t"w": 80,
+\t\t"h": 24,
+\t\t"x": 0,
+\t\t"y": 0,
+\t\t"i": 0,
+\t\t"I": "%s"
+\t}
+}' "$p0")"
+
+check_json_ok 'Carriage returns between tokens' \
+	"$(printf '{\r"V":2,\r"L":%s\r}' "$LEAF")"
+
+# A backslash makes the tokenizer consume the next character whatever it is, so
+# an escaped quote does not end the string. The key is not one that
+# layout-custom.c looks at, so all that is being checked is that the string
+# ended in the right place and the object still parsed.
+check_json_ok 'Escaped quote in a string' \
+	'{"V":2,"a\"b":0,"L":'"$LEAF"'}'
+
+# An escaped backslash immediately before the closing quote: the escape has to
+# be cleared again so that the quote after it does end the string.
+check_json_ok 'Escaped backslash before the closing quote' \
+	'{"V":2,"a\\":0,"L":'"$LEAF"'}'
+
+# Numbers and booleans, again on keys layout-custom.c ignores, so only json.c
+# decides whether they are accepted.
+check_json_ok 'Zero' '{"V":2,"n":0,"L":'"$LEAF"'}'
+check_json_ok 'Several digits' '{"V":2,"n":1234567,"L":'"$LEAF"'}'
+check_json_ok 'Negative number' '{"V":2,"n":-42,"L":'"$LEAF"'}'
+check_json_ok 'Booleans' '{"V":2,"b":true,"d":false,"L":'"$LEAF"'}'
+
+# Tokenizer failures. A value that runs to the end of the input has no
+# terminator, so it is the tokenizer rather than the parser that gives up. Both
+# the number scan and the string scan have to notice this, and with the closing
+# quote escaped there is no terminator left either.
+check_json_fail 'Unterminated number' '{"V":2'
+check_json_fail 'Unterminated string' '{"V":"x'
+check_json_fail 'Escaped closing quote' '{"V":2,"L":{"t":"p\"}}'
+
+# Something that is not a quoted string where a key belongs.
+check_json_fail 'Missing key' '{"V":2,,"L":'"$LEAF"'}'
+
+# A key not followed by ':'.
+check_json_fail 'Missing colon' '{"V","L":2}'
+
+# A bare word that is neither "true", "false" nor a number. This is where
+# "null" ends up.
+check_json_fail 'Unknown literal' '{"V":null,"L":'"$LEAF"'}'
+
+# A ':' with no value after it, so the token where the value belongs is one the
+# object parser has no case for.
+check_json_fail 'Missing value' '{"V":}'
+
+# A ',' with nothing after it, and a value with no ',' before the next key.
+check_json_fail 'Trailing comma in an object' '{"V":2,"L":'"$LEAF"',}'
+check_json_fail 'Missing comma in an object' '{"V":2 "L":'"$LEAF"'}'
+
+# Arrays hold objects and nothing else.
+check_json_fail 'Non-object in an array' \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":["x"]}}'
+check_json_fail 'Trailing comma in an array' \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":['"$LEAF"',]}}'
+
+# An empty string is two adjacent quotes with no value token between them,
+# which the string parser does not accept.
+check_json_fail 'Empty string' '{"V":2,"L":""}'
+
+# A number token that strtoll does not consume all of.
+check_json_fail 'Number with trailing characters' '{"V":8a,"L":'"$LEAF"'}'
+
+# Anything after the top level object.
+check_json_fail 'Data after the top level object' '{"V":2,"L":'"$LEAF"'}{}'
+
+# None of the rejections touched the layout.
+must_equal 'Layout after rejected parses' "$(layout L:one)" "$ONE"
+
+# ---------------------------------------------------------------------------
+# Dumping a split.
+
+check_ok new-window -d -t L:2 -n two
+q0=$($TMUX display-message -p -t L:two.0 '#{pane_id}')
+
+# -l 12 gives the new (bottom) pane 12 lines, leaving 11 for the top pane and
+# one for the border between them. With -d the top pane stays active.
+check_ok split-window -d -v -l 12 -t L:two.0
+q1=$($TMUX display-message -p -t L:two.1 '#{pane_id}')
+
+# Nothing has changed the active pane, so the last pane stack is still empty
+# and the bottom pane has neither "a" nor "l".
+must_equal 'Split layout' "$(layout L:two)" \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":11,"x":0,"y":0,"a":true,"i":0,"I":"%N"},{"t":"p","w":80,"h":12,"x":0,"y":12,"i":1,"I":"%N"}]}}'
+
+# ---------------------------------------------------------------------------
+# The active and last pane keys.
+
+# Selecting the bottom pane makes it active and pushes the top pane onto the
+# last pane stack, where it is at index 0.
+check_ok select-pane -t "$q1"
+must_equal 'Layout after select-pane' "$(layout L:two)" \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":11,"x":0,"y":0,"l":0,"i":0,"I":"%N"},{"t":"p","w":80,"h":12,"x":0,"y":12,"a":true,"i":1,"I":"%N"}]}}'
+
+# Selecting the top pane again swaps the two keys over. "i" and "I" do not
+# move: they are the pane's position in the window and its id.
+check_ok select-pane -t "$q0"
+SPLIT='{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":11,"x":0,"y":0,"a":true,"i":0,"I":"%N"},{"t":"p","w":80,"h":12,"x":0,"y":12,"l":0,"i":1,"I":"%N"}]}}'
+must_equal 'Layout after select-pane back' "$(layout L:two)" "$SPLIT"
+
+# ---------------------------------------------------------------------------
+# The visible layout.
+
+# With nothing zoomed the two layout formats agree.
+#
+# The zoomed case is deliberately not covered here. While a pane is zoomed
+# #{window_layout} dumps the saved (unzoomed) layout and
+# #{window_visible_layout} the zoomed one, but that depends on how zooming
+# stashes the layout root rather than on anything in layout-custom.c.
+must_equal 'Visible layout' "$(visible_layout L:two)" "$SPLIT"
+
+# ---------------------------------------------------------------------------
+# Round trip.
+
+# Make the two panes obviously uneven so that the layout applied in between
+# cannot be mistaken for the saved one. A resize shows up in the dump as the
+# new cell sizes and offsets.
+check_ok resize-pane -t "$q0" -y 5
+saved=$(raw_layout L:two)
+must_equal 'Resized layout' "$(layout L:two)" \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":5,"x":0,"y":0,"a":true,"i":0,"I":"%N"},{"t":"p","w":80,"h":18,"x":0,"y":6,"l":0,"i":1,"I":"%N"}]}}'
+
+check_ok select-layout -t L:two even-vertical
+must_differ 'Layout after even-vertical' "$(raw_layout L:two)" "$saved"
+
+# Parsing a dump gives back exactly the same dump, pane ids included. The panes
+# go back into the cells that named them: the cells are ordered by "i" and then
+# given the window's panes in order, so a cell dumped with "i":k must come back
+# the k'th.
+check_ok select-layout -t L:two "$saved"
+must_equal 'Round tripped layout' "$(raw_layout L:two)" "$saved"
+
+# ---------------------------------------------------------------------------
+# Parsing a hand-written layout.
+
+# Laid out over several lines to keep it readable; that the whitespace is
+# skipped at all is json.c's business, what matters here is that the cells come
+# out of it in the right shape.
+#
+# "a" and "l" are given on the cells so that the active pane and the last pane
+# stack are pinned by the layout rather than left to whatever a layout that
+# names neither happens to produce.
+check_ok select-layout -t L:two "$(printf '{
+	"V": 2,
+	"L": {
+		"t": "h",
+		"w": 80,
+		"h": 24,
+		"x": 0,
+		"y": 0,
+		"c": [
+			{"t": "p", "w": 30, "h": 24, "x": 0, "y": 0, "a": true, "i": 0, "I": "%s"},
+			{"t": "p", "w": 49, "h": 24, "x": 31, "y": 0, "l": 0, "i": 1, "I": "%s"}
+		]
+	}
+}' "$q0" "$q1")"
+must_equal 'Hand-written layout' "$(layout L:two)" \
+	'{"V":2,"L":{"t":"h","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":30,"h":24,"x":0,"y":0,"a":true,"i":0,"I":"%N"},{"t":"p","w":49,"h":24,"x":31,"y":0,"l":0,"i":1,"I":"%N"}]}}'
+
+# The panes are assigned to the cells in order.
+must_equal 'First pane width' \
+	"$($TMUX display-message -p -t "$q0" '#{pane_width}')" '30'
+must_equal 'Second pane width' \
+	"$($TMUX display-message -p -t "$q1" '#{pane_width}')" '49'
+
+# ---------------------------------------------------------------------------
+# Field order.
+
+# Fields are looked up by key once the object has been parsed, so the order
+# they are written in must give the same layout. Here every object has its keys
+# reversed: "c" comes before "t" and "V" comes after "L", neither of which
+# changes the order they are read in - the cell type is always read before the
+# children and the version before the layout.
+check_ok select-layout -t L:two \
+	'{"L":{"c":[{"I":"'"$q0"'","i":0,"a":true,"y":0,"x":0,"h":8,"w":80,"t":"p"},{"I":"'"$q1"'","i":1,"l":0,"y":9,"x":0,"h":15,"w":80,"t":"p"}],"y":0,"x":0,"h":24,"w":80,"t":"v"},"V":2}'
+must_equal 'Reversed field order' "$(layout L:two)" \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":8,"x":0,"y":0,"a":true,"i":0,"I":"%N"},{"t":"p","w":80,"h":15,"x":0,"y":9,"l":0,"i":1,"I":"%N"}]}}'
+
+# Keys interleaved rather than simply reversed, with "c" in the middle. This
+# time "a" is on the second cell, so the second pane becomes the active one:
+# which pane is active comes from the layout, while "i" and "I" still come from
+# the window. The first cell names neither "a" nor "l", so its pane is neither
+# active nor on the last pane stack and the dump gives it neither key.
+check_ok select-layout -t L:two \
+	'{"V":2,"L":{"h":24,"c":[{"w":40,"t":"p","y":0,"i":0,"h":24,"I":"'"$q0"'","x":0},{"a":true,"h":24,"I":"'"$q1"'","w":39,"y":0,"t":"p","i":1,"x":41}],"w":80,"y":0,"t":"h","x":0}}'
+must_equal 'Scrambled field order' "$(layout L:two)" \
+	'{"V":2,"L":{"t":"h","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":40,"h":24,"x":0,"y":0,"i":0,"I":"%N"},{"t":"p","w":39,"h":24,"x":41,"y":0,"a":true,"i":1,"I":"%N"}]}}'
+
+# ---------------------------------------------------------------------------
+# The legacy (v1) format.
+
+# The layout just applied, in v1: a left/right cell is written with braces and
+# a top/bottom cell with brackets, and each leaf carries its pane id without
+# the leading %.
+v1body="80x24,0,0{40x24,0,0,${q0#%},39x24,41,0,${q1#%}}"
+
+# A control client that has not asked for new layouts is dumped v1.
+must_equal 'v1 dump' "$(v1_layout L:two)" "$(v1 "$v1body")"
+
+# With the new-layouts flag the same client is dumped v2 instead. The flag is
+# set with "attach -f" rather than refresh-client because refresh-client needs
+# a current client, which a control client that has not attached has not got.
+got=$(printf "display-message -p -t L:two '#{window_layout}'\n" |
+	$TMUX -C attach -f new-layouts -t L 2>&1 | grep -v '^%')
+must_contain 'v2 dump for control client' "$got" '{"V":2,"L":'
+
+# A v1 layout with a correct checksum is parsed, and dumping v1 again gives
+# back the same string. That is the whole of what v1 carries: the cells take
+# the sizes and offsets from the body, and the panes are assigned to them in
+# order, which is what puts the same two ids back in the same two places. It is
+# checked in v1 rather than against a v2 dump so that nothing v1 has no opinion
+# on - the active pane, the last pane stack, the pane index - comes into it.
+v1vsplit="80x24,0,0[80x11,0,0,${q0#%},80x12,0,12,${q1#%}]"
+check_ok select-layout -t L:two "$(v1 "$v1vsplit")"
+must_equal 'v1 round trip' "$(v1_layout L:two)" "$(v1 "$v1vsplit")"
+
+# v1 names no active pane, last pane or z-index and must disturb none of them.
+# Applying the v1 form of the layout the window already has therefore leaves
+# even the v2 dump the same byte for byte, last pane stack included.
+check_ok select-pane -t "$q1"
+check_ok select-pane -t "$q0"
+before=$(raw_layout L:two)
+check_ok select-layout -t L:two "$(v1 "$v1vsplit")"
+must_equal 'v1 leaves the active and last panes alone' \
+	"$(raw_layout L:two)" "$before"
+
+# A v1 layout with more cells than the window has panes is trimmed like any
+# other: the bottom right cell is closed and the cell above it takes its eight
+# rows and the border between them, leaving 16. Pane ids in a v1 body are not
+# used to place panes, so the third cell can carry any id.
+v1three="80x24,0,0[80x7,0,0,${q0#%},80x7,0,8,${q1#%},80x8,0,16,999]"
+check_ok select-layout -t L:two "$(v1 "$v1three")"
+must_equal 'v1 layout trimmed' "$(v1_layout L:two)" \
+	"$(v1 "80x24,0,0[80x7,0,0,${q0#%},80x16,0,8,${q1#%}]")"
+
+# ---------------------------------------------------------------------------
+# Pane assignment order.
+
+# "i" is what decides which pane goes into which cell: the cells are ordered by
+# it and then handed the window's panes in order, so the cell with "i":0 takes
+# the first pane of the window wherever that cell sits in the layout. Here the
+# cells are written the other way round from their indexes - the first cell in
+# the string is "i":1 and the second "i":0 - so the first pane of the window
+# has to come out in the second cell.
+#
+# Every other layout above lists its cells in the same order as their indexes,
+# which is the order the tree is walked in, so this is the only check that can
+# tell the two apart.
+check_ok select-layout -t L:two \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":8,"x":0,"y":0,"i":1,"I":"'"$q1"'"},{"t":"p","w":80,"h":15,"x":0,"y":9,"i":0,"I":"'"$q0"'"}]}}'
+must_equal 'First pane height' \
+	"$($TMUX display-message -p -t "$q0" '#{pane_height}')" '15'
+must_equal 'Second pane height' \
+	"$($TMUX display-message -p -t "$q1" '#{pane_height}')" '8'
+
+# So the dump carries the two ids the other way round from every dump above,
+# and with them their indexes, which are the panes' positions in the window and
+# have not moved. Neither cell named an active or last pane, so the pane that
+# was active still is - it is now the one in the second cell.
+swapped='{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":8,"x":0,"y":0,"i":1,"I":"'"$q1"'"},{"t":"p","w":80,"h":15,"x":0,"y":9,"a":true,"i":0,"I":"'"$q0"'"}]}}'
+must_equal 'Layout with the panes swapped' "$(raw_layout L:two)" "$swapped"
+
+# And that dump round trips, indexes out of order and all.
+check_ok select-layout -t L:two "$swapped"
+must_equal 'Round tripped swapped layout' "$(raw_layout L:two)" "$swapped"
+
+# ---------------------------------------------------------------------------
+# Cells that name no active or last pane.
+
+# "a" and "l" are the only things that decide which pane is active and what is
+# on the last pane stack, so a layout naming neither leaves the active pane
+# where it was and empties the stack. Here the first pane of the window is
+# active and the second is at index 0 of the stack beforehand; afterwards the
+# first pane is still active and the stack is empty, so the second pane has no
+# "l".
+check_ok select-pane -t "$q1"
+check_ok select-pane -t "$q0"
+check_ok select-layout -t L:two \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":9,"x":0,"y":0,"i":0,"I":"'"$q0"'"},{"t":"p","w":80,"h":14,"x":0,"y":10,"i":1,"I":"'"$q1"'"}]}}'
+must_equal 'Layout naming no active pane' "$(layout L:two)" \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":9,"x":0,"y":0,"a":true,"i":0,"I":"%N"},{"t":"p","w":80,"h":14,"x":0,"y":10,"i":1,"I":"%N"}]}}'
+
+# "a" may be given as false, which says the same as leaving it out: this pane
+# is not the active one. A layout where every cell says so names no active pane
+# at all and so leaves the active pane alone, exactly as the layout above did.
+check_ok select-layout -t L:two \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":10,"x":0,"y":0,"a":false,"i":0,"I":"'"$q0"'"},{"t":"p","w":80,"h":13,"x":0,"y":11,"a":false,"i":1,"I":"'"$q1"'"}]}}'
+must_equal 'Layout with only false active panes' "$(layout L:two)" \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":10,"x":0,"y":0,"a":true,"i":0,"I":"%N"},{"t":"p","w":80,"h":13,"x":0,"y":11,"i":1,"I":"%N"}]}}'
+
+# ---------------------------------------------------------------------------
+# Failures.
+#
+# Each of these is a different reason for a layout to be rejected, but only the
+# rejection itself is checked; the message that comes back with it is not.
+
+# check_layout_fail $layout
+#
+# select-layout must reject $layout.
+check_layout_fail()
+{
+	check_fail select-layout -t L:two "$1"
+}
+
+# A rejected layout must leave the window alone, whatever it was.
+unchanged=$(raw_layout L:two)
+
+# Not JSON and not a checksum.
+check_layout_fail 'garbage'
+
+# A v1 body with its checksum left off, and a string of nothing but hex digits.
+# A v1 header is four hex digits and a comma; neither of these has one, so there
+# is no header and nothing to check a body against.
+check_layout_fail '80x24,0,0'
+check_layout_fail 'ab'
+
+# A v1 header with the checksum of a different body.
+good=$(v1 '80x24,0,0')
+check_layout_fail "${good%%,*},80x24,0,1"
+
+# A correct checksum over a body that is not a layout: a cell with no offsets,
+# and a top to bottom cell closed with '}' instead of ']'. layout_construct_v1
+# returns NULL for both.
+check_layout_fail "$(v1 '80x24')"
+check_layout_fail "$(v1 '80x24,0,0[80x11,0,0,80x12,0,12}')"
+
+# Fewer cells than the window has panes; unlike the other way around this
+# cannot be fixed up.
+check_layout_fail '{"V":2,"L":{"t":"p","w":80,"h":24,"x":0,"y":0,"i":0,"I":"'"$q0"'"}}'
+
+# The children of a top to bottom cell must all be the width of their parent.
+check_layout_fail \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":11,"x":0,"y":0,"i":0,"I":"'"$q0"'"},{"t":"p","w":40,"h":12,"x":0,"y":12,"i":1,"I":"'"$q1"'"}]}}'
+
+# The rest are valid JSON, so it is layout_parse_json() and
+# layout_parse_json_layout() doing the rejecting rather than json.c. Each of
+# them is a layout that would be applied but for the one thing being checked.
+
+# Two root cells.
+check_layout_fail \
+	'{"V":2,"L":{"t":"p","w":80,"h":24,"x":0,"y":0,"i":0,"I":"'"$q0"'"},"L":{"t":"p","w":80,"h":24,"x":0,"y":0,"i":0,"I":"'"$q0"'"}}'
+
+# A missing "y". A cell needs all four of "w", "h", "x" and "y".
+check_layout_fail '{"V":2,"L":{"t":"p","w":80,"h":24,"x":0,"i":0,"I":"'"$q0"'"}}'
+
+# Cell sizes are bounded below by one column or row and above by 10000 of
+# either. Both cases are otherwise complete two cell layouts, so the size is
+# the only thing wrong with them.
+check_layout_fail \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":11,"x":0,"y":0,"i":0,"I":"'"$q0"'"},{"t":"p","w":0,"h":12,"x":0,"y":12,"i":1,"I":"'"$q1"'"}]}}'
+check_layout_fail \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":11,"x":0,"y":0,"i":0,"I":"'"$q0"'"},{"t":"p","w":80,"h":10001,"x":0,"y":12,"i":1,"I":"'"$q1"'"}]}}'
+
+# An unknown cell type: only "h", "v" and "p" exist.
+check_layout_fail '{"V":2,"L":{"t":"q","w":80,"h":24,"x":0,"y":0}}'
+
+# A pane cell needs "i", its pane index. It is "i" that says which pane goes in
+# the cell; "I" is the pane id the cell was dumped with and is not read back.
+check_layout_fail '{"V":2,"L":{"t":"p","w":80,"h":24,"x":0,"y":0,"I":"'"$q0"'"}}'
+
+# A node cell must have more than one child and a leaf cell must have none. A
+# node is written with no "c" at all, with an empty one and with a single child.
+check_layout_fail '{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0}}'
+check_layout_fail '{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[]}}'
+check_layout_fail \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":24,"x":0,"y":0,"i":0,"I":"'"$q0"'"}]}}'
+check_layout_fail \
+	'{"V":2,"L":{"t":"p","w":80,"h":24,"x":0,"y":0,"i":0,"I":"'"$q0"'","c":[{"t":"p","w":80,"h":24,"x":0,"y":0,"i":1,"I":"'"$q1"'"}]}}'
+
+# Only one cell may be the active pane.
+check_layout_fail \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":11,"x":0,"y":0,"a":true,"i":0,"I":"'"$q0"'"},{"t":"p","w":80,"h":12,"x":0,"y":12,"a":true,"i":1,"I":"'"$q1"'"}]}}'
+
+# The same rejections apply whatever order the fields are written in: a leaf
+# with children when "c" comes first, and a node with no children and a bad cell
+# type when "t" comes last.
+check_layout_fail \
+	'{"V":2,"L":{"c":[{"t":"p","w":80,"h":24,"x":0,"y":0,"i":1,"I":"'"$q1"'"}],"t":"p","w":80,"h":24,"x":0,"y":0,"i":0,"I":"'"$q0"'"}}'
+check_layout_fail '{"V":2,"L":{"w":80,"h":24,"x":0,"y":0,"t":"v"}}'
+check_layout_fail '{"V":2,"L":{"w":80,"h":24,"x":0,"y":0,"t":"q"}}'
+
+# A child that fails after a sibling has already been parsed and added to the
+# parent. This is the case the cleanup at the end of layout_parse_json_layout
+# exists for: the children built so far have to be freed along with the parent
+# that is never returned. The second child has no "y".
+check_layout_fail \
+	'{"V":2,"L":{"c":[{"t":"p","w":80,"h":11,"x":0,"y":0,"i":0,"I":"'"$q0"'"},{"t":"p","w":80,"h":12,"x":0,"i":1,"I":"'"$q1"'"}],"t":"v","w":80,"h":24,"x":0,"y":0}}'
+
+# No root cell at all. Every other rejection above comes from a cell that
+# failed to parse; this one is the check for "L" itself.
+check_layout_fail '{"V":2}'
+
+# The wrong version, with "V" before and after "L". Fields are looked up by
+# key, so the version is read before the layout either way and the position of
+# "V" in the string makes no difference.
+check_layout_fail '{"V":1,"L":{"t":"p","w":80,"h":24,"x":0,"y":0,"i":0,"I":"'"$q0"'"}}'
+check_layout_fail '{"L":{"t":"p","w":80,"h":24,"x":0,"y":0,"i":0,"I":"'"$q0"'"},"V":1}'
+
+# None of that touched the layout.
+must_equal 'Layout after failures' "$(raw_layout L:two)" "$unchanged"
+
+# ---------------------------------------------------------------------------
+# Floating panes.
+
+check_ok new-window -d -t L:3 -n float
+check_ok select-window -t L:float
+check_ok new-pane -d -x 20 -y 6 -X 8 -Y 3 'sleep 100'
+check_ok new-pane -d -x 30 -y 8 -X 30 -Y 10 'sleep 100'
+
+# The tiled pane and the two floating ones. A floating pane goes on the end of
+# the window's pane list, so the pane indexes are in the order the panes were
+# made whatever order their cells end up in.
+f0=$($TMUX display-message -p -t L:float.0 '#{pane_id}')
+fa=$($TMUX display-message -p -t L:float.1 '#{pane_id}')
+fb=$($TMUX display-message -p -t L:float.2 '#{pane_id}')
+
+# A floating cell is dumped with its z-index, which is what marks it as
+# floating when the layout is parsed back. Two of them, so that there is an
+# order between them to get wrong: the newer floating pane is in front, and a
+# cell's "z" is its place in that order counting from the front.
+floating=$(raw_layout L:float)
+must_contain 'Floating layout front z-index' "$floating" '"z":0'
+must_contain 'Floating layout back z-index' "$floating" '"z":1'
+
+# Each floating cell goes in after the cell of the pane that was current when
+# it was made, which is the tiled pane both times, so the newer floating cell
+# is written before the older one while its pane comes after in the window.
+# The dump therefore has its cells in one order and their indexes in another,
+# and only comes back the same if the panes go by index.
+check_ok select-layout -t L:float "$floating"
+must_equal 'Floating layout after round trip' "$(raw_layout L:float)" "$floating"
+
+# ---------------------------------------------------------------------------
+# Floating panes and the legacy (v1) format.
+#
+# v1 has no way to write a floating pane down, so the two formats cannot say the
+# same thing about a window that has one. Dumping v1 takes a copy of the layout,
+# deletes the floating cells from the copy and dumps what is left; parsing v1
+# rearranges the tiled panes and leaves the floating ones where they are. None
+# of this is reached above: every v1 check so far runs on a window that has no
+# floating panes, and every floating pane check so far is in v2.
+
+# float_state $target
+#
+# Everything about a floating pane that a v1 layout has no way to carry, so that
+# applying one can be checked against all of it at once.
+float_state()
+{
+	$TMUX display-message -p -t "$1" \
+		'#{pane_floating_flag} #{pane_width}x#{pane_height} #{pane_left},#{pane_top} #{pane_z}'
+}
+
+# Deleting both floating cells from the copy leaves the root node with a single
+# child, and a node with a single child collapses into it, so the root of the
+# copy is the tiled cell and the dump is that cell on its own filling the
+# window.
+must_equal 'v1 dump with floating panes' "$(v1_layout L:float)" \
+	"$(v1 "80x24,0,0,${f0#%}")"
+
+# The cells are deleted from the copy, so the window itself comes through a v1
+# dump untouched - floating panes, z-indexes and all.
+must_equal 'Layout after a v1 dump' "$(raw_layout L:float)" "$floating"
+
+# The same with a split, where deleting the floating cell still leaves two
+# children behind and the node it was in does not collapse.
+check_ok new-window -d -t L:4 -n mixed
+m0=$($TMUX display-message -p -t L:mixed.0 '#{pane_id}')
+check_ok split-window -d -v -l 12 -t L:mixed.0
+m1=$($TMUX display-message -p -t L:mixed.1 '#{pane_id}')
+check_ok new-pane -d -x 20 -y 6 -X 8 -Y 3 -t L:mixed.0 'sleep 100'
+mf=$($TMUX display-message -p -t L:mixed.2 '#{pane_id}')
+
+# A floating pane takes no space from the tiled layout, so the two tiled cells
+# are the same 11 and 12 rows the split gave them.
+must_equal 'v1 dump with a split and a floating pane' "$(v1_layout L:mixed)" \
+	"$(v1 "80x24,0,0[80x11,0,0,${m0#%},80x12,0,12,${m1#%}]")"
+
+# A v1 layout applied to a window that has a floating pane rearranges the tiled
+# panes and must leave the floating one exactly as it was: v1 names no floating
+# pane, so there is nothing in it for one to be changed by. The top pane goes
+# from 11 rows to 7 and the bottom one from 12 to 16.
+v1mixed="80x24,0,0[80x7,0,0,${m0#%},80x16,0,8,${m1#%}]"
+mfbefore=$(float_state "$mf")
+check_ok select-layout -t L:mixed "$(v1 "$v1mixed")"
+must_equal 'v1 layout with a floating pane' "$(v1_layout L:mixed)" \
+	"$(v1 "$v1mixed")"
+must_equal 'Floating pane after a v1 layout' "$(float_state "$mf")" "$mfbefore"
+must_equal 'Panes after a v1 layout' \
+	"$($TMUX display-message -p -t L:mixed '#{window_panes}')" '3'
+
+# When the tiled layout a v1 string names is a single cell there is no node in
+# the new layout for the floating cells to go back into, so one is made: the
+# root cell is replaced by a top to bottom node holding it and the floating
+# cells go on the end. Nothing else here reaches that.
+fabefore=$(float_state "$fa")
+fbbefore=$(float_state "$fb")
+check_ok select-layout -t L:float "$(v1 "80x24,0,0,${f0#%}")"
+must_equal 'v1 single cell layout with floating panes' "$(v1_layout L:float)" \
+	"$(v1 "80x24,0,0,${f0#%}")"
+must_equal 'Front floating pane after a v1 layout' "$(float_state "$fb")" \
+	"$fbbefore"
+must_equal 'Back floating pane after a v1 layout' "$(float_state "$fa")" \
+	"$fabefore"
+must_equal 'Panes after a v1 single cell layout' \
+	"$($TMUX display-message -p -t L:float '#{window_panes}')" '3'
+
+# Adjacent subtrees containing only floating panes used to be a distinct case:
+# dumping v1 made a copy of the v2 tree and deleted floating cells from the
+# copy, but deleting the last floating cell in the first subtree collapsed the
+# parent and could leave the outer traversal holding a stale pointer to the
+# second subtree.
+check_ok new-window -d -t L:5 -n nested
+n0=$($TMUX display-message -p -t L:nested.0 '#{pane_id}')
+check_ok split-window -d -v -l 12 -t L:nested.0
+n1=$($TMUX display-message -p -t L:nested.1 '#{pane_id}')
+check_ok split-window -d -v -l 6 -t L:nested.1
+n2=$($TMUX display-message -p -t L:nested.2 '#{pane_id}')
+check_ok split-window -d -v -l 3 -t L:nested.2
+n3=$($TMUX display-message -p -t L:nested.3 '#{pane_id}')
+check_ok split-window -d -v -l 2 -t L:nested.3
+n4=$($TMUX display-message -p -t L:nested.4 '#{pane_id}')
+check_ok select-layout -t L:nested \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"h","w":30,"h":10,"x":0,"y":0,"c":[{"t":"p","w":10,"h":5,"x":2,"y":2,"i":0,"z":0},{"t":"p","w":12,"h":6,"x":5,"y":5,"i":1,"z":1}]},{"t":"h","w":30,"h":10,"x":0,"y":0,"c":[{"t":"p","w":14,"h":7,"x":8,"y":8,"i":2,"z":2},{"t":"p","w":16,"h":8,"x":11,"y":11,"i":3,"z":3}]},{"t":"p","w":80,"h":24,"x":0,"y":0,"i":4}]}}'
+must_equal 'v1 dump with nested floating-only subtrees' \
+	"$(v1_layout L:nested)" "$(v1 "80x24,0,0,${n4#%}")"
+check_ok kill-window -t L:nested
+
+# ---------------------------------------------------------------------------
+# A window with no tiled panes.
+#
+# Killing the last tiled pane of a window that has floating panes does not kill
+# the window: that only happens when the pane being killed is the last one
+# counting the floating ones. What is left is a window whose layout root is
+# either a floating cell on its own, or a node holding nothing but floating
+# cells, depending on how many are left. v1 has no way to write either down, so
+# it must not try: a layout with no tiled panes in it produces no v1 dump at
+# all, and #{window_layout} comes back empty for a client being sent v1. What v2
+# makes of such a window is a separate question and is not checked here.
+#
+# A dead server dumps nothing either, so the checks below have to establish that
+# the server is still there before an empty dump is allowed to mean anything.
+
+# no_hang $cmd...
+#
+# Run a command whose result is not being checked, but which has to come back:
+# only the server surviving it is checked afterwards, and a server wedged rather
+# than killed would otherwise show up as the test never finishing.
+no_hang()
+{
+	if command -v timeout >/dev/null 2>&1; then
+		timeout 10 "$@" >/dev/null 2>&1
+	else
+		"$@" >/dev/null 2>&1
+	fi
+	return 0
+}
+
+# One floating pane left. The node it and the tiled cell were in is down to a
+# single child, so it collapses and the floating cell becomes the root.
+check_ok new-window -d -t L:5 -n gone1
+g0=$($TMUX display-message -p -t L:gone1.0 '#{pane_id}')
+check_ok new-pane -d -x 20 -y 6 -X 8 -Y 3 -t L:gone1.0 'sleep 100'
+check_ok kill-pane -t "$g0"
+must_equal 'Panes left with one floating pane' \
+	"$($TMUX display-message -p -t L:gone1 '#{window_panes}')" '1'
+
+# The floating cell is the root and there is nothing tiled under it, so there is
+# no v1 dump to make. In particular the floating cell must not be written out on
+# its own, which would be a layout claiming the window is the size and position
+# of the floating pane with no pane in it at all.
+got=$(v1_layout L:gone1)
+check_ok display-message -p alive
+must_equal 'v1 dump with one floating pane and no tiled panes' "$got" ''
+
+# Two floating panes left, so the node keeps two children, does not collapse,
+# and stays the root with nothing but floating cells in it.
+check_ok new-window -d -t L:6 -n gone2
+h0=$($TMUX display-message -p -t L:gone2.0 '#{pane_id}')
+check_ok new-pane -d -x 20 -y 6 -X 8 -Y 3 -t L:gone2.0 'sleep 100'
+check_ok new-pane -d -x 30 -y 8 -X 30 -Y 10 -t L:gone2.0 'sleep 100'
+check_ok kill-pane -t "$h0"
+must_equal 'Panes left with two floating panes' \
+	"$($TMUX display-message -p -t L:gone2 '#{window_panes}')" '2'
+
+# The node is the root this time rather than the floating cell, but it has no
+# tiled cell anywhere under it either, so there is still no v1 dump to make -
+# and making one must not take the server with it.
+got=$(v1_layout L:gone2)
+check_ok display-message -p alive
+must_equal 'v1 dump with two floating panes and no tiled panes' "$got" ''
+
+# Nor must parsing a v1 layout against it. There is no tiled pane for the
+# layout to name, so whether it is applied or rejected is the format's business;
+# it just has to be one of the two.
+no_hang $TMUX select-layout -t L:gone2 "$(v1 '80x24,0,0,999')"
+check_ok display-message -p alive
+
+check_ok kill-window -t L:gone1
+check_ok kill-window -t L:gone2
+
+# ---------------------------------------------------------------------------
+# Control mode notifications.
+#
+# %layout-change is what a control client actually reads a layout from, and it
+# carries both #{window_layout} and #{window_visible_layout}. Its template is
+# expanded once per client (control-notify.c), so two clients watching the same
+# window must be told about the same change in different formats: v1 for the
+# one that has not asked for new layouts, v2 for the one that has.
+#
+# The dumps above go through "-C display-message", which only ever reaches the
+# format callbacks for the client asking. This needs clients that stay
+# attached while something else changes the layout, so they go on the end of
+# fifos and the change is made from outside.
+
+DIR=$(mktemp -d) || fail 'Could not make a temporary directory'
+OLDIN="$DIR/old-in"
+OLDOUT="$DIR/old-out"
+NEWIN="$DIR/new-in"
+NEWOUT="$DIR/new-out"
+OLDPID=
+NEWPID=
+
+cleanup()
+{
+	[ -n "$OLDPID" ] && kill "$OLDPID" 2>/dev/null
+	[ -n "$NEWPID" ] && kill "$NEWPID" 2>/dev/null
+	$TMUX kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup EXIT
+
+# wait_for $file $text
+#
+# Wait for $text to appear in a control client's output.
+wait_for()
+{
+	i=0
+	while [ "$i" -lt 6 ]; do
+		grep -F -- "$2" "$1" >/dev/null 2>&1 && return 0
+		sleep 1
+		i=$((i + 1))
+	done
+	echo "missing from $1: $2" >&2
+	cat "$1" >&2
+	return 1
+}
+
+mkfifo "$OLDIN" "$NEWIN" || fail 'Could not make the control client fifos'
+: >"$OLDOUT"
+: >"$NEWOUT"
+
+$TMUX -C attach -t L <"$OLDIN" >"$OLDOUT" 2>&1 &
+OLDPID=$!
+exec 4>"$OLDIN"
+$TMUX -C attach -f new-layouts -t L <"$NEWIN" >"$NEWOUT" 2>&1 &
+NEWPID=$!
+exec 5>"$NEWIN"
+
+# Both clients have to be attached before the layout changes, or they miss the
+# notification entirely.
+printf 'display-message -p ready\n' >&4
+printf 'display-message -p ready\n' >&5
+wait_for "$OLDOUT" ready || fail 'Control client without new-layouts did not attach'
+wait_for "$NEWOUT" ready || fail 'Control client with new-layouts did not attach'
+
+wid=$($TMUX display-message -p -t L:two '#{window_id}')
+
+# One layout change, made by a third client so that neither of the two is the
+# one running the command. 8 lines for the top pane leaves 15 for the bottom
+# and one for the border.
+check_ok resize-pane -t "$q0" -y 8
+
+# Nothing is zoomed, so both fields of the notification carry the same layout.
+# The v2 one is compared against the dump rather than a literal so that it is
+# the two formats being checked and not the geometry again.
+v2now=$(raw_layout L:two)
+v1now=$(v1 "80x24,0,0[80x8,0,0,${q0#%},80x15,0,9,${q1#%}]")
+wait_for "$NEWOUT" "%layout-change $wid $v2now $v2now " ||
+	fail 'No v2 %layout-change for the client with new-layouts'
+wait_for "$OLDOUT" "%layout-change $wid $v1now $v1now " ||
+	fail 'No v1 %layout-change for the client without new-layouts'
+
+# How many notifications one layout change produces, which differs by format
+# on purpose. cmd_select_layout_exec() fires window-layout-changed for any
+# layout it applies, and layout_parse() fires it again for a v1 one, so v1
+# arrives twice - which is what master does for every layout, and what control
+# clients written against it expect. v2 is new and has no such clients, so it
+# gets the single notification. Counting the delta rather than the total, with
+# a settle in between, keeps this independent of what has already been sent.
+n1=$(grep -c "%layout-change $wid " "$OLDOUT")
+check_ok select-layout -t L:two \
+	'{"V":2,"L":{"t":"v","w":80,"h":24,"x":0,"y":0,"c":[{"t":"p","w":80,"h":9,"x":0,"y":0,"i":0,"I":"'"$q0"'"},{"t":"p","w":80,"h":14,"x":0,"y":10,"i":1,"I":"'"$q1"'"}]}}'
+sleep 2
+n2=$(grep -c "%layout-change $wid " "$OLDOUT")
+must_equal 'Notifications for a v2 layout' "$((n2 - n1))" '1'
+
+check_ok select-layout -t L:two "$(v1 "$v1vsplit")"
+sleep 2
+n3=$(grep -c "%layout-change $wid " "$OLDOUT")
+must_equal 'Notifications for a v1 layout' "$((n3 - n2))" '2'
+
+# And the client that did not ask for new layouts must never have been sent
+# one, in that notification or any other.
+grep -F '{"V":2,' "$OLDOUT" >/dev/null 2>&1 &&
+	fail 'Control client without new-layouts was sent a v2 layout'
+
+if [ "$($TMUX display-message -p alive 2>&1)" != "alive" ]; then
+	echo "Server died." >&2
+	exit 1
+fi
+
+$TMUX kill-server 2>/dev/null
+exit 0

regress/layout-nesting-limit.sh

@@ -0,0 +1,77 @@
+#!/bin/sh
+
+# Version 1 layouts must reject excessive nesting without losing the session or
+# changing its layout. Check both split types and the depth limit boundary.
+
+PATH=/bin:/usr/bin
+TERM=screen
+export PATH TERM
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+DIR=$(mktemp -d) || exit 1
+TMUX="$TEST_TMUX -S$DIR/socket -f/dev/null"
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$TMUX kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0
+trap 'exit 1' 1 2 15
+
+# Generate a checksum-valid v1 layout with one child in every nested group.
+layout()
+{
+	awk -v depth="$1" -v open="$2" 'BEGIN {
+		closing = (open == "{" ? "}" : "]")
+		body = ""
+		for (i = 0; i < depth; i++)
+			body = body "1x1,0,0" open
+		body = body "1x1,0,0"
+		for (i = 0; i < depth; i++)
+			body = body closing
+
+		ord["0"] = 48; ord["1"] = 49; ord["x"] = 120
+		ord[","] = 44; ord["{"] = 123; ord["}"] = 125
+		ord["["] = 91; ord["]"] = 93
+		csum = 0
+		for (i = 1; i <= length(body); i++) {
+			c = substr(body, i, 1)
+			bit = csum % 2
+			csum = int(csum / 2) + bit * 32768
+			csum = (csum + ord[c]) % 65536
+		}
+		printf "%04x,%s", csum, body
+	}'
+}
+
+$TMUX new-session -d -s deep -x80 -y24 'exec sleep 100' || exit 1
+
+for open in '{' '['; do
+	# A valid checksum and nesting up to the limit must still be accepted.
+	value=$(layout 1000 "$open") || fail "could not generate layout"
+	$TMUX select-layout -t deep "$value" ||
+		fail "layout at the depth limit was rejected ($open)"
+	before=$($TMUX display-message -p -t deep \
+	    '#{pane_id} #{pane_width} #{pane_height} #{window_layout}') || exit 1
+
+	for depth in 1001 1500; do
+		value=$(layout "$depth" "$open") || fail "could not generate layout"
+		$TMUX select-layout -t deep "$value" >/dev/null 2>&1 &&
+			fail "excessive nesting was accepted ($open, $depth)"
+		$TMUX has-session -t deep ||
+			fail "server died on excessive nesting ($open, $depth)"
+		after=$($TMUX display-message -p -t deep \
+		    '#{pane_id} #{pane_width} #{pane_height} #{window_layout}') || exit 1
+		[ "$before" = "$after" ] ||
+			fail "pane or layout changed after rejection ($open, $depth)"
+	done
+done
+
+exit 0

regress/layout-set.sh

@@ -0,0 +1,126 @@
+#!/bin/sh
+
+# Exercise every predefined layout, next/previous cycling, lookup and restore
+# paths, one-pane early returns, minimum-size handling and floating panes.
+
+PATH=/bin:/usr/bin
+TERM=screen
+export PATH TERM
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+DIR=$(mktemp -d) || exit 1
+TMUX_TMPDIR=$DIR
+export TMUX_TMPDIR
+TMUX="$TEST_TMUX -Ltest$$ -f/dev/null"
+SEEN="$DIR/layouts"
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$TMUX kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+layout()
+{
+	$TMUX display-message -p -t layouts:many '#{window_layout}'
+}
+
+check_layout()
+{
+	name=$1
+	$TMUX select-layout -t layouts:many "$name" ||
+		fail "select-layout $name failed"
+	value=$(layout)
+	[ -n "$value" ] || fail "$name produced an empty layout"
+	if grep -Fxq "$value" "$SEEN"; then
+		fail "$name produced the same layout as an earlier preset"
+	fi
+	printf '%s\n' "$value" >>"$SEEN"
+	[ "$($TMUX list-panes -t layouts:many -F x | wc -l)" -eq 5 ] ||
+		fail "$name lost a pane"
+	[ "$($TMUX list-panes -t layouts:many -F '#{pane_floating_flag}' | \
+	    grep -c '^1$')" -eq 1 ] || fail "$name did not preserve the floating pane"
+}
+
+$TMUX new-session -d -s layouts -n many -x100 -y40 'exec sleep 100' || exit 1
+$TMUX set-option -g window-size manual || exit 1
+$TMUX split-window -d -h -t layouts:many 'exec sleep 100' || exit 1
+$TMUX split-window -d -v -t layouts:many 'exec sleep 100' || exit 1
+$TMUX split-window -d -h -t layouts:many 'exec sleep 100' || exit 1
+floating=$($TMUX new-pane -dP -F '#{pane_id}' -t layouts:many \
+    -x20 -y8 -X10 -Y5 'exec sleep 100') || exit 1
+: >"$SEEN"
+
+# Options exercise percentage and explicit secondary-size calculations.
+$TMUX set-option -w -t layouts:many main-pane-height 30% || exit 1
+$TMUX set-option -w -t layouts:many other-pane-height 12 || exit 1
+$TMUX set-option -w -t layouts:many main-pane-width 35% || exit 1
+$TMUX set-option -w -t layouts:many other-pane-width 20 || exit 1
+
+for name in even-horizontal even-vertical main-horizontal \
+    main-horizontal-mirrored main-vertical main-vertical-mirrored tiled; do
+	check_layout "$name"
+done
+
+# Exact and unique-prefix lookup work; ambiguous and invalid names fail.
+$TMUX select-layout -t layouts:many even-h || fail "unique layout prefix failed"
+$TMUX select-layout -t layouts:many main >/dev/null 2>&1 &&
+	fail "ambiguous layout prefix succeeded"
+$TMUX select-layout -t layouts:many no-such-layout >/dev/null 2>&1 &&
+	fail "invalid layout name succeeded"
+
+# Cycle through all layouts in both directions, including wraparound. The
+# aliases and select-layout flags share layout_set_next/previous.
+first=$(layout)
+i=0
+while [ "$i" -lt 7 ]; do
+	$TMUX next-layout -t layouts:many || exit 1
+	i=$((i + 1))
+done
+[ "$(layout)" = "$first" ] || fail "next-layout did not wrap"
+i=0
+while [ "$i" -lt 7 ]; do
+	$TMUX previous-layout -t layouts:many || exit 1
+	i=$((i + 1))
+done
+[ "$(layout)" = "$first" ] || fail "previous-layout did not wrap"
+$TMUX select-layout -t layouts:many -n || exit 1
+$TMUX select-layout -t layouts:many -p || exit 1
+
+# No argument reapplies the last preset; -o restores the previous layout; -E
+# spreads the current cell without changing the pane set.
+$TMUX kill-pane -t "$floating" || exit 1
+$TMUX select-layout -t layouts:many tiled || exit 1
+tiled=$(layout)
+$TMUX select-layout -t layouts:many even-horizontal || exit 1
+$TMUX select-layout -t layouts:many -o || exit 1
+[ "$(layout)" = "$tiled" ] || fail "select-layout -o did not restore layout"
+$TMUX select-layout -t layouts:many || exit 1
+$TMUX select-layout -t layouts:many -E || exit 1
+
+# Each arranger has a deliberate one-pane early return.
+$TMUX new-window -d -t layouts: -n one 'exec sleep 100' || exit 1
+one=$($TMUX display-message -p -t layouts:one '#{window_layout}')
+for name in even-horizontal even-vertical main-horizontal \
+    main-horizontal-mirrored main-vertical main-vertical-mirrored tiled; do
+	$TMUX select-layout -t layouts:one "$name" || exit 1
+	[ "$($TMUX display-message -p -t layouts:one '#{window_layout}')" = "$one" ] ||
+		fail "$name changed a one-pane layout"
+done
+
+# Force the minimum-size paths without requiring a terminal client.
+$TMUX resize-window -t layouts:many -x10 -y6 || exit 1
+for name in even-horizontal even-vertical main-horizontal \
+    main-horizontal-mirrored main-vertical main-vertical-mirrored tiled; do
+	$TMUX select-layout -t layouts:many "$name" || exit 1
+done
+
+$TMUX has-session -t layouts || fail "server died during layout tests"
+exit 0

regress/list-commands.sh

@@ -0,0 +1,46 @@
+#!/bin/sh
+
+# Exercise list-commands for the full table, a single command, aliases, custom
+# and empty formats, and lookup errors.
+
+PATH=/bin:/usr/bin
+TERM=screen
+export PATH TERM
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+DIR=$(mktemp -d) || exit 1
+TMUX_TMPDIR=$DIR
+export TMUX_TMPDIR
+TMUX="$TEST_TMUX -Ltest$$ -f/dev/null"
+
+cleanup()
+{
+	$TMUX kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+# Keep a server alive across commands. Otherwise a STARTSERVER-only command
+# may exit between invocations and leave a short socket-cleanup race.
+$TMUX new-session -d -s list-commands 'exec sleep 100' || exit 1
+
+all=$($TMUX list-commands) || exit 1
+printf '%s\n' "$all" | grep -q '^attach-session (attach)' || exit 1
+printf '%s\n' "$all" | grep -q '^list-commands (lscm)' || exit 1
+
+one=$($TMUX list-commands -F \
+    '#{command_list_name}|#{command_list_alias}|#{command_list_usage}' \
+    list-commands) || exit 1
+case "$one" in
+'list-commands|lscm|'*) ;;
+*) exit 1 ;;
+esac
+
+# Aliases resolve to their command, while an empty expansion prints no line.
+[ "$($TMUX list-commands -F '#{command_list_name}' lscm)" = list-commands ] ||
+	exit 1
+[ -z "$($TMUX list-commands -F '' list-commands)" ] || exit 1
+
+$TMUX list-commands tmux-no-command-$$ >/dev/null 2>&1 && exit 1
+$TMUX list-commands list >/dev/null 2>&1 && exit 1
+exit 0

regress/modal-pane.sh

@@ -105,6 +105,24 @@ drag()
 	sleep 1
 }
 
+meta_drag()
+{
+	scol="$1"
+	srow="$2"
+	ecol="$3"
+	erow="$4"
+
+	seq=$(printf '\033[<8;%s;%sM' "$scol" "$srow")
+	$TMUX2 send-keys -t "$OUTER" -l "$seq" 2>/dev/null
+	sleep 0.2
+	seq=$(printf '\033[<40;%s;%sM' "$ecol" "$erow")
+	$TMUX2 send-keys -t "$OUTER" -l "$seq" 2>/dev/null
+	sleep 0.2
+	seq=$(printf '\033[<8;%s;%sm' "$ecol" "$erow")
+	$TMUX2 send-keys -t "$OUTER" -l "$seq" 2>/dev/null
+	sleep 1
+}
+
 cleanup
 
 check_ok new-session -d -s modal -x 80 -y 24 'cat'
@@ -127,12 +145,16 @@ case "$(fmt "$modal" '#{pane_flags}')" in
 *O*) ;;
 *) fail "modal pane flags do not include O" ;;
 esac
+case "$(fmt "$modal" '#{pane_flags}')" in
+*A*) ;;
+*) fail "modal pane flags do not include A" ;;
+esac
 case "$(fmt modal:0 '#{window_flags}')" in
 *O*) ;;
 *) fail "modal window flags do not include O" ;;
 esac
 must_equal "$(fmt modal:0 '#{window_modal_pane}')" "$modal"
-must_equal "$(fmt modal:0 '#{window_zoomed_flag}')" 0
+must_equal "$(fmt modal:0 '#{window_zoomed_flag}')" 1
 
 check_fail "window already has a modal pane" \
 	new-pane -O -x 10 -y 4 'cat'
@@ -159,12 +181,14 @@ under=$($TMUX split-window -PF '#{pane_id}' -t "$p0" 'cat') ||
 sleep 1
 must_equal "$(fmt modal:0 '#{pane_id}')" "$modal"
 must_equal "$(fmt "$under" '#{pane_active}')" 0
+must_equal "$(fmt modal:0 '#{window_zoomed_flag}')" 1
 
 float=$($TMUX new-pane -PF '#{pane_id}' -x 10 -y 4 -X 5 -Y 3 'cat') ||
 	fail "new floating pane under modal failed"
 sleep 1
 must_equal "$(fmt modal:0 '#{pane_id}')" "$modal"
 must_equal "$(fmt "$float" '#{pane_active}')" 0
+must_equal "$(fmt modal:0 '#{window_zoomed_flag}')" 1
 
 check_ok new-window -d -t modal: -n other 'cat'
 check_ok select-window -t modal:other
@@ -303,6 +327,164 @@ check_ok kill-pane -t "$modal"
 sleep 1
 must_equal "$(fmt modal:0 '#{window_modal_pane}')" ''
 must_equal "$(fmt modal:0 '#{pane_id}')" "$p0"
+must_equal "$(fmt "$p0" '#{window_zoomed_flag}:#{pane_zoomed_flag}')" 0:0
+
+ignored=$($TMUX new-pane -KdPF '#{pane_id}' -t "$p0" 'cat') ||
+	fail "new-pane -K without -O failed"
+check_ok kill-pane -t "$ignored"
+
+$TMUX set -g @modal-prefix no
+$TMUX set -g @modal-root no
+$TMUX bind -n z set -g @modal-root yes
+
+modal=$($TMUX new-pane -OKPF '#{pane_id}' -t "$p0" \
+    -x 20 -y 5 -X 20 -Y 10 'cat') ||
+	fail "new-pane -OK failed"
+sleep 1
+$TMUX2 send-keys -t "$OUTER" C-b x z Enter
+sleep 1
+must_equal "$($TMUX show -gv @modal-prefix)" no
+must_equal "$($TMUX show -gv @modal-root)" no
+case "$($TMUX capture-pane -pt "$modal")" in
+*xz*) ;;
+*) fail "keys did not reach key-capturing modal pane" ;;
+esac
+left=$(fmt "$modal" '#{pane_left}')
+top=$(fmt "$modal" '#{pane_top}')
+meta_drag $((left + 2)) $((top + 2)) $((left + 7)) $((top + 4))
+new_left=$(fmt "$modal" '#{pane_left}')
+new_top=$(fmt "$modal" '#{pane_top}')
+[ "$new_left" -gt "$left" ] || [ "$new_top" -gt "$top" ] ||
+	fail "key-capturing modal pane did not move"
+check_ok kill-pane -t "$modal"
+sleep 1
+
+# A nonmodal floating pane may remain above zoom, and switching between it and
+# the zoomed tiled pane must not unzoom the window.
+check_ok new-window -d -t modal: -n float-over-zoom 'cat'
+base=$(fmt modal:float-over-zoom '#{pane_id}')
+check_ok split-window -dh -t "$base" 'cat'
+check_ok resize-pane -Z -t "$base"
+over=$($TMUX new-pane -APF '#{pane_id}' -t "$base" \
+    -x 20 -y 5 -X 20 -Y 10 'cat') ||
+	fail "new-pane -A failed"
+must_equal "$(fmt "$over" '#{pane_floating_flag}:#{pane_active}')" 1:1
+case "$(fmt "$over" '#{pane_flags}')" in
+*A*) ;;
+*) fail "float-over-zoom pane flags do not include A" ;;
+esac
+must_equal "$(fmt "$base" '#{window_zoomed_flag}:#{pane_zoomed_flag}')" 1:1
+check_ok select-pane -t "$base"
+must_equal "$(fmt "$base" '#{window_zoomed_flag}:#{pane_active}')" 1:1
+check_ok select-pane -t "$over"
+must_equal "$(fmt "$over" '#{window_zoomed_flag}:#{pane_active}')" 1:1
+client=$($TMUX list-clients -F '#{client_name}' | head -1)
+[ -n "$client" ] || fail "no client for switch-client test"
+check_ok switch-client -c "$client" -t "$base"
+must_equal "$(fmt "$base" '#{window_zoomed_flag}:#{pane_active}')" 1:1
+check_ok switch-client -c "$client" -t "$over"
+must_equal "$(fmt "$over" '#{window_zoomed_flag}:#{pane_active}')" 1:1
+check_ok kill-pane -t "$over"
+must_equal "$(fmt "$base" '#{window_zoomed_flag}:#{pane_zoomed_flag}')" 1:1
+check_ok resize-pane -Z -t "$base"
+
+ignored=$($TMUX new-pane -ALdPF '#{pane_id}' -t "$base" 'cat') ||
+	fail "new-pane -A -L failed"
+case "$(fmt "$ignored" '#{pane_flags}')" in
+*A*) fail "tiled pane flags include A" ;;
+*) ;;
+esac
+
+# Existing floating panes are filtered when zoom begins: -A panes remain in the
+# visible layout and ordinary floating panes do not.
+check_ok new-window -d -t modal: -n existing-over-zoom 'cat'
+base=$(fmt modal:existing-over-zoom '#{pane_id}')
+check_ok split-window -dh -t "$base" 'cat'
+over=$($TMUX new-pane -AdPF '#{pane_id}' -t "$base" \
+    -x 20 -y 5 -X 20 -Y 10 'cat') ||
+	fail "pre-existing new-pane -A failed"
+under=$($TMUX new-pane -dPF '#{pane_id}' -t "$base" \
+    -x 15 -y 4 -X 2 -Y 2 'cat') ||
+	fail "pre-existing ordinary new-pane failed"
+check_ok select-window -t modal:existing-over-zoom
+check_ok select-pane -t "$base"
+check_ok resize-pane -Z -t "$base"
+must_equal "$(fmt "$over" '#{pane_floating_flag}')" 1
+must_equal "$(fmt "$under" '#{pane_floating_flag}')" 0
+must_equal "$(fmt "$base" '#{window_zoomed_flag}:#{pane_zoomed_flag}')" 1:1
+
+# Geometry changed in the visible zoom layout is copied back when unzooming.
+check_ok select-pane -t "$over"
+left=$(fmt "$over" '#{pane_left}')
+top=$(fmt "$over" '#{pane_top}')
+meta_drag $((left + 2)) $((top + 2)) $((left + 7)) $((top + 4))
+new_left=$(fmt "$over" '#{pane_left}')
+new_top=$(fmt "$over" '#{pane_top}')
+[ "$new_left" -gt "$left" ] || [ "$new_top" -gt "$top" ] ||
+	fail "float-over-zoom pane did not move"
+must_equal "$(fmt "$base" '#{window_zoomed_flag}:#{pane_zoomed_flag}')" 1:1
+check_ok resize-pane -Z -t "$base"
+must_equal "$(fmt "$over" '#{pane_left}:#{pane_top}')" \
+    "$new_left:$new_top"
+must_equal "$(fmt "$under" '#{pane_floating_flag}')" 1
+
+# Resizing with the over-zoom pane active restores the original zoom target.
+check_ok resize-pane -Z -t "$base"
+check_ok select-pane -t "$over"
+check_ok resize-window -t modal:existing-over-zoom -x 90 -y 30
+must_equal "$(fmt "$base" \
+    '#{window_width}x#{window_height}:#{window_zoomed_flag}:#{pane_zoomed_flag}')" \
+    90x30:1:1
+must_equal "$(fmt "$over" '#{pane_floating_flag}:#{pane_active}')" 1:1
+
+# Natural pane exit uses a different removal path from kill-pane and must also
+# preserve zoom.
+dying=$($TMUX new-pane -AdPF '#{pane_id}' -t "$base" \
+    -x 12 -y 4 -X 4 -Y 3 'true') ||
+	fail "short-lived new-pane -A failed"
+i=0
+while $TMUX list-panes -a -F '#{pane_id}' | grep -qx "$dying"; do
+    i=$((i + 1))
+    [ $i -gt 50 ] && fail "short-lived float-over-zoom pane did not exit"
+    sleep 0.1
+done
+must_equal "$(fmt "$base" '#{window_zoomed_flag}:#{pane_zoomed_flag}')" 1:1
+
+# A pane with -A is also above a zoom target which was itself floating. The
+# temporary tiled target must sit behind retained floating panes, then return
+# to the normal floating z order when unzoomed.
+check_ok new-window -d -t modal: -n floating-zoom-target 'cat'
+base=$(fmt modal:floating-zoom-target '#{pane_id}')
+check_ok split-window -dh -t "$base" 'cat'
+target=$($TMUX new-pane -dPF '#{pane_id}' -t "$base" \
+    -x 30 -y 10 -X 10 -Y 5 'cat') ||
+	fail "floating zoom target creation failed"
+over=$($TMUX new-pane -AdPF '#{pane_id}' -t "$base" \
+    -x 15 -y 5 -X 15 -Y 8 'cat') ||
+	fail "float-over-zoom pane creation failed"
+check_ok select-window -t modal:floating-zoom-target
+check_ok select-pane -t "$target"
+must_equal "$(fmt "$target" '#{pane_z}')" 0
+must_equal "$(fmt "$over" '#{pane_z}')" 1
+
+check_ok resize-pane -Z -t "$target"
+must_equal "$(fmt "$target" \
+    '#{window_zoomed_flag}:#{pane_zoomed_flag}:#{pane_floating_flag}:#{pane_z}')" \
+    1:1:0:2
+must_equal "$(fmt "$over" '#{pane_floating_flag}:#{pane_z}')" 1:0
+check_ok select-pane -t "$over"
+must_equal "$(fmt "$over" '#{window_zoomed_flag}:#{pane_active}')" 1:1
+check_ok resize-pane -Z -t "$target"
+must_equal "$(fmt "$over" '#{pane_active}:#{pane_z}')" 1:0
+must_equal "$(fmt "$target" '#{pane_floating_flag}:#{pane_z}')" 1:1
+
+# If the target remains active, it returns to the front on unzoom.
+check_ok select-pane -t "$target"
+check_ok resize-pane -Z -t "$target"
+must_equal "$(fmt "$over" '#{pane_floating_flag}:#{pane_z}')" 1:0
+check_ok resize-pane -Z -t "$target"
+must_equal "$(fmt "$target" '#{pane_active}:#{pane_z}')" 1:0
+must_equal "$(fmt "$over" '#{pane_z}')" 1
 
 cleanup
 exit 0

regress/pane-ops.sh

@@ -19,7 +19,10 @@
 # - respawn-pane/respawn-window refusing a live pane without -k, working on a
 #   dead pane (remain-on-exit) and killing with -k;
 # - resize-pane -x/-y in cells and percent, -L/-R/-U/-D adjustments and -Z
-#   zoom/unzoom (including implicit unzoom on split).
+#   zoom/unzoom, layout round trips, zoom target selection, pane removal,
+#   window resizing and implicit unzoom on layout changes;
+# - swap-pane preserving one or two zoomed windows, including cross-window
+#   swaps of hidden panes and zoom targets.
 #
 # window-ops.sh covers window-level commands and buffers.sh paste buffers.
 
@@ -144,7 +147,8 @@ check_panes P:0 "0:$p3 1:$p0 2:$p2 3:$p1"
 # break-pane and join-pane.
 
 # break-pane moves a pane to a new window; -P -F prints where it went and -n
-# names the new window.
+# names the new window. Moving a pane out of a zoomed window unzooms it first.
+check_ok resize-pane -Z -t "$p0"
 out=$($TMUX break-pane -d -P -F '#{window_index}:#{pane_id}' -n broken \
 	-s "$p1" -t P:)
 if [ "$out" != "1:$p1" ]; then
@@ -153,10 +157,14 @@ if [ "$out" != "1:$p1" ]; then
 fi
 check_fmt 'P:1' '#{window_name}:#{window_panes}' 'broken:1'
 check_fmt 'P:0' '#{window_panes}' '3'
+check_fmt 'P:0' '#{window_zoomed_flag}' '0'
 
-# join-pane -v moves it back (the source window, left empty, is destroyed).
+# join-pane -v moves it back (the source window, left empty, is destroyed) and
+# also unzooms the destination before changing its layout.
+check_ok resize-pane -Z -t "$p0"
 check_ok join-pane -d -v -s P:broken.0 -t "$p2"
 check_fmt 'P:0' '#{window_panes}' '4'
+check_fmt 'P:0' '#{window_zoomed_flag}' '0'
 if $TMUX has-session -t P:broken 2>/dev/null; then
 	echo "Window 'broken' still exists after join-pane."
 	exit 1
@@ -299,6 +307,122 @@ check_fmt 'P:0' '#{window_panes}' '5'
 p6=$($TMUX display-message -p -t P:0.2 '#{pane_id}')
 check_ok kill-pane -t "$p6"
 
+# Zoom and unzoom preserve the exact tiled layout. Selecting another pane
+# without -Z unzooms, while -Z transfers zoom to the selected pane.
+layout=$($TMUX display-message -p -t P:0 '#{window_layout}')
+check_ok select-pane -t "$p0"
+check_ok resize-pane -Z -t "$p0"
+check_ok select-pane -t "$p2"
+check_fmt "$p2" '#{window_zoomed_flag}:#{pane_active}' '0:1'
+check_fmt P:0 '#{window_layout}' "$layout"
+
+check_ok select-pane -t "$p0"
+check_ok resize-pane -Z -t "$p0"
+check_ok select-pane -Z -t "$p2"
+check_fmt "$p2" '#{window_zoomed_flag}:#{pane_zoomed_flag}:#{pane_active}' \
+	'1:1:1'
+check_ok resize-pane -Z -t "$p2"
+check_fmt P:0 '#{window_layout}' "$layout"
+
+# Directional selection temporarily restores the full layout to find its
+# neighbour, then follows the same unzoom or -Z transfer rules.
+check_ok select-pane -t "$p0"
+check_ok resize-pane -Z -t "$p0"
+check_ok select-pane -t "$p0"
+check_fmt "$p0" '#{window_zoomed_flag}:#{pane_zoomed_flag}:#{pane_active}' \
+	'1:1:1'
+check_ok select-pane -D -t "$p0"
+check_fmt "$p2" '#{window_zoomed_flag}:#{pane_active}' '0:1'
+
+check_ok select-pane -t "$p0"
+check_ok resize-pane -Z -t "$p0"
+check_ok select-pane -D -Z -t "$p0"
+check_fmt "$p2" '#{window_zoomed_flag}:#{pane_zoomed_flag}:#{pane_active}' \
+	'1:1:1'
+check_ok resize-pane -Z -t "$p2"
+check_fmt P:0 '#{window_layout}' "$layout"
+
+# The last-pane path has separate zoom handling, both with and without -Z.
+check_ok select-pane -t "$p0"
+check_ok select-pane -t "$p2"
+check_ok resize-pane -Z -t "$p2"
+check_ok select-pane -l -t P:0
+check_fmt "$p0" '#{window_zoomed_flag}:#{pane_zoomed_flag}:#{pane_active}' \
+	'0:0:1'
+
+check_ok select-pane -t "$p0"
+check_ok select-pane -t "$p2"
+check_ok resize-pane -Z -t "$p2"
+check_ok select-pane -l -Z -t P:0
+check_fmt "$p0" '#{window_zoomed_flag}:#{pane_zoomed_flag}:#{pane_active}' \
+	'1:1:1'
+check_ok resize-pane -Z -t "$p0"
+check_fmt P:0 '#{window_layout}' "$layout"
+
+# Killing either a hidden ordinary pane or the zoom target unzooms.
+check_ok new-window -d -t P:12 -n zoom-kill 'cat'
+zk0=$($TMUX display-message -p -t P:12.0 '#{pane_id}')
+zk1=$($TMUX split-window -d -P -F '#{pane_id}' -t P:12.0 'cat')
+zk2=$($TMUX split-window -d -P -F '#{pane_id}' -t P:12.0 'cat')
+check_ok resize-pane -Z -t "$zk0"
+check_ok kill-pane -t "$zk1"
+check_fmt "$zk0" '#{window_panes}:#{window_zoomed_flag}:#{pane_zoomed_flag}' \
+	'2:0:0'
+check_ok resize-pane -Z -t "$zk0"
+check_ok kill-pane -t "$zk0"
+check_fmt "$zk2" '#{window_panes}:#{window_zoomed_flag}:#{pane_zoomed_flag}' \
+	'1:0:0'
+check_ok kill-window -t P:12
+
+# The same cases through natural process exit exercise server_destroy_pane.
+check_ok new-window -d -t P:13 -n zoom-exit 'cat'
+ze0=$($TMUX display-message -p -t P:13.0 '#{pane_id}')
+ze1=$($TMUX split-window -d -P -F '#{pane_id}' -t P:13.0 'cat')
+ze2=$($TMUX split-window -d -P -F '#{pane_id}' -t P:13.0 'cat')
+check_ok resize-pane -Z -t "$ze0"
+check_ok send-keys -t "$ze1" C-d
+i=0
+while [ "$($TMUX display-message -p -t P:13 '#{window_panes}')" != 2 ]; do
+	i=$((i + 1))
+	[ $i -gt 50 ] && { echo "Hidden pane did not exit."; exit 1; }
+	sleep 0.1
+done
+check_fmt "$ze0" '#{window_zoomed_flag}:#{pane_zoomed_flag}' '0:0'
+check_ok resize-pane -Z -t "$ze2"
+check_ok send-keys -t "$ze2" C-d
+i=0
+while [ "$($TMUX display-message -p -t P:13 '#{window_panes}')" != 1 ]; do
+	i=$((i + 1))
+	[ $i -gt 50 ] && { echo "Zoomed pane did not exit."; exit 1; }
+	sleep 0.1
+done
+check_fmt "$ze0" '#{window_zoomed_flag}:#{pane_zoomed_flag}' '0:0'
+check_ok kill-window -t P:13
+
+# resize-window restores both tiled and floating zoom targets after rebuilding
+# the layout at the new size.
+check_ok new-window -d -t P:14 -n zoom-resize 'cat'
+zr0=$($TMUX display-message -p -t P:14.0 '#{pane_id}')
+check_ok split-window -d -t P:14.0 'cat'
+check_ok resize-pane -Z -t "$zr0"
+check_ok resize-window -t P:14 -x 90 -y 30
+check_fmt "$zr0" \
+	'#{window_width}x#{window_height}:#{window_zoomed_flag}:#{pane_zoomed_flag}' \
+	'90x30:1:1'
+check_ok resize-pane -Z -t "$zr0"
+zrf=$($TMUX new-pane -dP -F '#{pane_id}' -t P:14 -x 20 -y 6 'cat')
+zrf_size=$($TMUX display-message -p -t "$zrf" \
+	'#{pane_width}x#{pane_height}')
+check_ok resize-pane -Z -t "$zrf"
+check_ok resize-window -t P:14 -x 100 -y 32
+check_fmt "$zrf" \
+	'#{window_width}x#{window_height}:#{window_zoomed_flag}:#{pane_zoomed_flag}' \
+	'100x32:1:1'
+check_ok resize-pane -Z -t "$zrf"
+check_fmt "$zrf" '#{pane_floating_flag}:#{pane_width}x#{pane_height}' \
+	"1:$zrf_size"
+check_ok kill-window -t P:14
+
 # ---------------------------------------------------------------------------
 # kill-pane.
 
@@ -307,8 +431,10 @@ check_ok kill-pane -t "$p3"
 check_panes P:0 "0:$p0 1:$p2 2:$p1"
 
 # -a kills every pane except the target.
+check_ok resize-pane -Z -t "$p0"
 check_ok kill-pane -a -t "$p0"
 check_panes P:0 "0:$p0"
+check_fmt "$p0" '#{window_zoomed_flag}:#{pane_zoomed_flag}' '0:0'
 
 # Killing the last pane in a window kills the window.
 check_ok new-window -d -t P:7 -n goner
@@ -516,6 +642,10 @@ check_panes P:3 "0:$r0 1:$r1 2:$r2"
 # Swapping a pane with itself quietly does nothing.
 check_ok swap-pane -d -s "$r1" -t "$r1"
 check_panes P:3 "0:$r0 1:$r1 2:$r2"
+check_ok resize-pane -Z -t "$r1"
+check_ok swap-pane -d -Z -s "$r1" -t "$r1"
+check_fmt "$r1" '#{window_zoomed_flag}:#{pane_zoomed_flag}' '1:1'
+check_ok resize-pane -Z -t "$r1"
 
 # Panes can be swapped between different windows.
 check_ok swap-pane -d -s "$o0" -t "$r1"
@@ -525,10 +655,38 @@ check_ok swap-pane -d -s "$r1" -t "$o0"
 check_panes P:3 "0:$r0 1:$r1 2:$r2"
 check_panes P:5 "0:$o0"
 
+# With both windows zoomed, -Z preserves each window's zoom when hidden panes
+# are exchanged and when the zoom targets themselves are exchanged.
+o1=$($TMUX split-window -dP -F '#{pane_id}' -t P:5.0)
+check_ok resize-pane -Z -t "$r0"
+check_ok resize-pane -Z -t "$o0"
+check_ok swap-pane -d -Z -s "$r1" -t "$o1"
+check_fmt "$r0" \
+	'#{window_name}:#{window_zoomed_flag}:#{pane_zoomed_flag}' 'swaps:1:1'
+check_fmt "$o0" \
+	'#{window_name}:#{window_zoomed_flag}:#{pane_zoomed_flag}' 'other:1:1'
+check_fmt "$r1" '#{window_name}' 'other'
+check_fmt "$o1" '#{window_name}' 'swaps'
+
+check_ok swap-pane -d -Z -s "$r0" -t "$o0"
+check_fmt "$o0" \
+	'#{window_name}:#{window_zoomed_flag}:#{pane_zoomed_flag}' 'swaps:1:1'
+check_fmt "$r0" \
+	'#{window_name}:#{window_zoomed_flag}:#{pane_zoomed_flag}' 'other:1:1'
+check_ok resize-pane -Z -t "$o0"
+check_ok resize-pane -Z -t "$r0"
+
+# Restore the original panes before the remaining swap tests.
+check_ok swap-pane -d -s "$r0" -t "$o0"
+check_ok swap-pane -d -s "$r1" -t "$o1"
+check_ok kill-pane -t "$o1"
+check_panes P:3 "0:$r0 1:$r1 2:$r2"
+check_panes P:5 "0:$o0"
+
 # -Z keeps the window zoomed across the swap.
 check_ok resize-pane -Z -t "$r0"
 check_ok swap-pane -d -Z -s "$r0" -t "$r1"
-check_fmt 'P:3' '#{window_zoomed_flag}' '1'
+check_fmt "$r0" '#{window_zoomed_flag}:#{pane_zoomed_flag}' '1:1'
 check_ok resize-pane -Z -t P:3
 check_panes P:3 "0:$r1 1:$r0 2:$r2"
 

regress/prompt-keys.sh

@@ -217,7 +217,36 @@ $OUT send-keys M-r || exit 1
 settle
 status_line | grep -q '>' || fail "status-line prompt not drawn on the status line"
 
-# --- 11. emacs cursor-marker edit, accept recovers the exact buffer. ---
+# --- 11. Invalid UTF-8 input must not desynchronize the prompt buffer. ---
+$OUT send-keys -H e6 85 5f || exit 1	# invalid UTF-8, then "_"
+settle
+$IN display-message -p '#{version}' >/dev/null 2>&1 || \
+	fail "invalid UTF-8 append killed inner tmux"
+status_line | grep -qF "> _" || \
+	fail "invalid UTF-8 append did not keep prompt usable (got '$(status_line)')"
+$OUT send-keys Enter || exit 1
+settle
+[ "$($IN show -gv @r)" = "_" ] || \
+	fail "invalid UTF-8 append recovered '$($IN show -gv @r)', wanted '_'"
+
+$IN set -g @r "SENTINEL" || exit 1
+$OUT send-keys M-r || exit 1
+settle
+$OUT send-keys -H e6 85 04 || exit 1	# invalid UTF-8, then C-d
+settle
+$IN display-message -p '#{version}' >/dev/null 2>&1 || \
+	fail "invalid UTF-8 delete killed inner tmux"
+status_line | grep -q '>' || \
+	fail "invalid UTF-8 delete closed the prompt (got '$(status_line)')"
+$OUT send-keys Escape || exit 1
+settle
+[ "$($IN show -gv @r)" = "SENTINEL" ] || \
+	fail "invalid UTF-8 delete accepted the prompt"
+
+# --- 12. emacs cursor-marker edit, accept recovers the exact buffer. ---
+$IN set -g @r "" || exit 1
+$OUT send-keys M-r || exit 1
+settle
 $OUT send-keys -l "abc" || exit 1
 $OUT send-keys Home || exit 1
 $OUT send-keys -l "X" || exit 1
@@ -229,7 +258,7 @@ settle
 [ "$($IN show -gv @r)" = "Xabc" ] || \
 	fail "status-line accept recovered '$($IN show -gv @r)', wanted 'Xabc'"
 
-# --- 12. Unicode on the status line: insert, move, delete wide char. ---
+# --- 13. Unicode on the status line: insert, move, delete wide char. ---
 $IN set -g @r "" || exit 1
 $OUT send-keys M-r || exit 1
 settle
@@ -249,7 +278,7 @@ settle
 [ "$($IN show -gv @r)" = "Za" ] || \
 	fail "status-line wide edit recovered '$($IN show -gv @r)', wanted 'Za'"
 
-# --- 13. Overflow: more text than fits stays within the line and is kept. ---
+# --- 14. Overflow: more text than fits stays within the line and is kept. ---
 big="0123456789012345678901234567890123456789012345678901234567890123456789ABCDEFGHIJ"
 $IN set -g @r "" || exit 1
 $OUT send-keys M-r || exit 1
@@ -264,7 +293,7 @@ settle
 # The whole buffer was kept despite only part being visible.
 [ "$($IN show -gv @r)" = "$big" ] || fail "overflowing prompt lost buffer content"
 
-# --- 14. Escape closes the status-line prompt cleanly. ---
+# --- 15. Escape closes the status-line prompt cleanly. ---
 $IN set -g @r "SENTINEL" || exit 1
 $OUT send-keys M-r || exit 1
 settle

regress/prompt-words-history.sh

@@ -0,0 +1,165 @@
+#!/bin/sh
+
+# Cover prompt word movement in emacs and vi modes, ambiguous inline command
+# completion, and the show/clear-prompt-history command surface.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+DIR=$(mktemp -d) || exit 1
+TMUX_TMPDIR=$DIR
+export TMUX_TMPDIR
+INNER="$TEST_TMUX -LtestI$$ -f/dev/null"
+OUTER="$TEST_TMUX -LtestO$$ -f/dev/null"
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$OUTER kill-server 2>/dev/null
+	$INNER kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+capture()
+{
+	$OUTER capture-pane -p -t outer:0.0 2>/dev/null
+}
+
+wait_result()
+{
+	want=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		got=$($INNER show-option -gqv @result 2>/dev/null)
+		[ "$got" = "$want" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "prompt result is '$got', expected '$want'"
+}
+
+bind_prompt()
+{
+	initial=$1
+	$INNER bind-key -n M-r command-prompt -I "$initial" -p '(word)' \
+		"set-option -g @result '%%'" || exit 1
+}
+
+run_prompt()
+{
+	want=$1
+	shift
+	$INNER set-option -g @result sentinel || exit 1
+	$OUTER send-keys M-r || exit 1
+	sleep 0.2
+	$OUTER send-keys "$@" || exit 1
+	$OUTER send-keys Enter || exit 1
+	wait_result "$want"
+}
+
+run_vi_prompt()
+{
+	want=$1
+	shift
+	$INNER set-option -g @result sentinel || exit 1
+	$OUTER send-keys M-r || exit 1
+	sleep 0.2
+	# Send Escape separately so the terminal's escape-time handling does not
+	# combine it with the first vi command as a Meta key.
+	$OUTER send-keys Escape || exit 1
+	# The inner client must see Escape as a complete key, not the prefix of a
+	# Meta sequence (the default escape-time is 500 milliseconds).
+	sleep 0.7
+	$OUTER send-keys "$@" || exit 1
+	$OUTER send-keys Enter || exit 1
+	wait_result "$want"
+}
+
+$INNER new-session -d -s prompt -x80 -y24 'exec sleep 100' || exit 1
+$INNER set-option -g status on || exit 1
+$INNER set-option -g status-position bottom || exit 1
+$INNER set-option -g window-size manual || exit 1
+$OUTER new-session -d -s outer -x80 -y24 "$INNER attach -t prompt" || exit 1
+$OUTER set-option -g status off || exit 1
+$OUTER set-option -g window-size manual || exit 1
+sleep 1
+
+# Emacs Meta-f stops after the first word; Meta-b returns to the start of the
+# previous word. Inserting a marker makes the cursor position observable.
+$INNER set-option -g status-keys emacs || exit 1
+bind_prompt 'one two'
+run_prompt 'oneX two' Home M-f X
+bind_prompt 'one two'
+run_prompt 'one Xtwo' M-b X
+
+# Vi translation and the distinct separator-aware and WORD motions.
+$INNER set-option -g status-keys vi || exit 1
+bind_prompt 'one-two three'
+run_vi_prompt 'one-two Xthree' b i X
+bind_prompt 'one-two three'
+run_vi_prompt 'one-two Xthree' B i X
+bind_prompt 'one-two three'
+run_vi_prompt 'oneX-two three' 0 w i X
+bind_prompt 'one-two three'
+run_vi_prompt 'one-two Xthree' 0 W i X
+bind_prompt 'one-two three'
+run_vi_prompt 'oneX-two three' 0 e a X
+bind_prompt 'one-two three'
+run_vi_prompt 'one-twoX three' 0 E a X
+
+# "show-" has several command matches and no longer common prefix. Tab keeps
+# the input and draws the sorted candidates inline.
+$INNER set-option -g status-keys emacs || exit 1
+bind_prompt ''
+$OUTER send-keys M-r || exit 1
+sleep 0.2
+$OUTER send-keys -l 'show-' || exit 1
+$OUTER send-keys Tab || exit 1
+sleep 0.2
+captured=$(capture)
+printf '%s\n' "$captured" | grep -Fq 'show-buffer' ||
+	fail "ambiguous completion list was not drawn"
+printf '%s\n' "$captured" | grep -Fq 'show-environment' ||
+	fail "ambiguous completion list was incomplete"
+$OUTER send-keys Escape || exit 1
+
+# Add entries to both history rings through real prompts.
+bind_prompt 'history-command'
+run_prompt 'history-command'
+$INNER bind-key -n M-s command-prompt -T search -I history-search \
+	-p '(search-history)' "set-option -g @result '%%'" || exit 1
+$OUTER send-keys M-s || exit 1
+$OUTER send-keys Enter || exit 1
+wait_result history-search
+
+command_history=$($INNER show-prompt-history -T command) || exit 1
+printf '%s\n' "$command_history" | grep -Fq 'history-command' ||
+	fail "command history entry missing"
+search_history=$($INNER show-prompt-history -T search) || exit 1
+printf '%s\n' "$search_history" | grep -Fq 'history-search' ||
+	fail "search history entry missing"
+all_history=$($INNER show-prompt-history) || exit 1
+printf '%s\n' "$all_history" | grep -Fq 'History for command:' || exit 1
+printf '%s\n' "$all_history" | grep -Fq 'History for search:' || exit 1
+
+$INNER show-prompt-history -T invalid >/dev/null 2>&1 &&
+	fail "invalid show history type succeeded"
+$INNER clear-prompt-history -T invalid >/dev/null 2>&1 &&
+	fail "invalid clear history type succeeded"
+$INNER clear-prompt-history -T command || exit 1
+$INNER show-prompt-history -T command | grep -Fq history-command &&
+	fail "type-specific history clear failed"
+$INNER clear-prompt-history || exit 1
+$INNER show-prompt-history | grep -Fq history-search &&
+	fail "all-history clear failed"
+
+exit 0

regress/respawn-pane-control-lag.sh

@@ -0,0 +1,87 @@
+#!/bin/sh
+
+# respawn-pane frees the pane's buffer and creates an empty one. The pane
+# offsets and each control client's offsets used to keep pointing into the old
+# buffer, so if an attached control client had not caught up on the pane's
+# output, the next read from the new process ran off the end of the new buffer
+# and the server crashed in input_parse.
+#
+# Two ways for a client to be behind are tested: a control client whose output
+# goes down a fifo that is never read (a second, healthy control client keeps
+# the pane being read), and a healthy control client viewing a session that
+# the pane's window has been moved out of.
+
+PATH=/bin:/usr/bin
+TERM=screen
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+TMUX="$TEST_TMUX -Ltest"
+$TMUX kill-server 2>/dev/null
+
+DIR=$(mktemp -d)
+FIFO=$DIR/fifo
+SERVER=
+
+mkfifo "$FIFO" || exit 1
+
+cleanup() {
+	[ -n "$SERVER" ] && kill -9 "$SERVER" 2>/dev/null
+	$TMUX kill-server 2>/dev/null
+	exec 8<&- 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+alive() {
+	if ! kill -0 "$SERVER" 2>/dev/null; then
+		SERVER=
+		echo "server died after $1"
+		exit 1
+	fi
+	$TMUX has -t rt || exit 1
+}
+
+wait_clients() {
+	n=0
+	while [ $n -lt 50 ]; do
+		[ "$($TMUX lsc 2>/dev/null | wc -l)" -ge $1 ] && return
+		sleep 0.1
+		n=$((n + 1))
+	done
+	echo "control clients did not attach"; exit 1
+}
+
+# A detached session with a pane that writes a line every 10 milliseconds.
+$TMUX -f/dev/null new -d -x 80 -y 24 -s rt \
+	'while :; do echo xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx; sleep 0.01; done' ||
+	exit 1
+SERVER=$($TMUX display -pt rt '#{pid}')
+
+# One control client with output down the unread fifo and one reading
+# normally; stdin of both held open by sleep so they stay attached.
+( sleep 60 ) | $TMUX -f/dev/null -C attach -t rt >"$FIFO" 2>&1 &
+exec 8<"$FIFO"
+( sleep 60 ) | $TMUX -f/dev/null -C attach -t rt >/dev/null 2>&1 &
+wait_clients 2
+
+# Let the first client fall behind, then respawn the pane. The new process
+# writes at once and the server must survive reading it.
+sleep 3
+$TMUX respawn-pane -k -t rt:0 'echo respawned; sleep 60' || exit 1
+sleep 1
+alive "respawn-pane with a lagging control client"
+
+# Now a pane whose window is moved out of the session both clients view: their
+# offsets for it stop advancing, so they fall behind until it is respawned.
+$TMUX neww -d -t rt \
+	'while :; do echo yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy; sleep 0.01; done' ||
+	exit 1
+sleep 1
+$TMUX new -d -s other || exit 1
+$TMUX movew -d -s rt:1 -t other: || exit 1
+sleep 2
+$TMUX respawn-pane -k -t other:1 'echo respawned; sleep 60' || exit 1
+sleep 1
+alive "respawn-pane on a window moved out of the clients' session"
+
+exit 0

regress/screen-redraw-outside.sh

@@ -93,6 +93,15 @@ $TMUX2 splitw -v "$C" || exit 1
 $TMUX2 select-layout tiled || exit 1
 compare outside-both-2x2
 
+# Top pane status supplies internal horizontal borders, but there is no pane
+# below the window to supply its bottom edge.
+new_scene 28 9
+$TMUX2 setw pane-border-status top || exit 1
+$TMUX2 setw pane-border-format "" || exit 1
+compare outside-both-status-top-single
+$TMUX2 splitw -v "$C" || exit 1
+compare outside-both-status-top-split
+
 # Window BIGGER than the client: only part of the window is viewed and the view
 # can be panned (refresh-client). This exercises a non-zero scene offset.
 # A 2x2 grid in a 60x20 window viewed through the 40x14 client.

regress/screen-redraw-results/outside-both-status-top-single.result

@@ -0,0 +1,14 @@
+────────────────────────────┐···········
+OUT01 abcdefghij            │···········
+OUT02 abcdefghij            │···········
+OUT03 abcdefghij            │···········
+OUT04 abcdefghij            │···········
+OUT05 abcdefghij            │···········
+OUT06 abcdefghij            │···········
+OUT07 abcdefghij            │···········
+                            │···········
+────────────────────────────┘···········
+········································
+········································
+········································
+········································

regress/screen-redraw-results/outside-both-status-top-split.result

@@ -0,0 +1,14 @@
+────────────────────────────┐···········
+OUT06 abcdefghij            │···········
+OUT07 abcdefghij            │···········
+                            │···········
+────────────────────────────┤···········
+PAN05 abcdefghij            │···········
+PAN06 abcdefghij            │···········
+PAN07 abcdefghij            │···········
+                            │···········
+────────────────────────────┘···········
+········································
+········································
+········································
+········································

regress/screen-redraw-scrollbars-auto-hide.sh

@@ -0,0 +1,96 @@
+#!/bin/sh
+
+# Auto-hide scrollbars appear on activity or pointer hover, then disappear
+# after pane-scrollbars-timeout. Compare captures of the same copy-mode view so
+# only the overlay scrollbar changes.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+OUTER="$TEST_TMUX -LtestA$$ -f/dev/null"
+INNER="$TEST_TMUX -LtestB$$ -f/dev/null"
+DIR=$(mktemp -d) || exit 1
+HIDDEN=$DIR/hidden
+VISIBLE=$DIR/visible
+AFTER=$DIR/after
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$OUTER kill-server 2>/dev/null
+	$INNER kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+capture()
+{
+	$OUTER capture-pane -pe -t outer:0.0 >"$1" || exit 1
+}
+
+wait_for_client()
+{
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$INNER list-clients 2>/dev/null | grep -q . && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "inner client did not attach"
+}
+
+$INNER new-session -d -s inner -x40 -y12 \
+	"sh -c 'seq 50; exec sleep 100'" || exit 1
+$INNER set-option -g status off || exit 1
+$INNER set-option -g window-size manual || exit 1
+$INNER set-option -g mouse on || exit 1
+$INNER set-window-option pane-scrollbars auto-hide || exit 1
+$INNER set-window-option pane-scrollbars-timeout 3000 || exit 1
+$INNER set-window-option pane-scrollbars-style \
+	'bg=colour196,fg=colour231,width=1,pad=0' || exit 1
+
+$OUTER new-session -d -s outer -x40 -y12 "$INNER attach -t inner" || exit 1
+$OUTER set-option -g status off || exit 1
+$OUTER set-option -g window-size manual || exit 1
+wait_for_client
+
+# Enter copy mode and choose a stable view. The initial show timer is allowed
+# to expire before taking the hidden reference capture.
+$INNER copy-mode -H || exit 1
+$INNER send-keys -X history-top || exit 1
+sleep 3.5
+capture "$HIDDEN"
+
+# A copy-mode page movement shows the overlay and starts its timer. Capture
+# that view immediately, then again after the timeout without moving it.
+$INNER send-keys -X page-down || exit 1
+sleep 0.1
+capture "$VISIBLE"
+sleep 3.5
+capture "$AFTER"
+cmp -s "$VISIBLE" "$AFTER" && fail "scrollbar did not hide after timeout"
+
+# Use the post-movement hidden scene as the reference for pointer hover. SGR
+# mouse column 40 is the right-hand scrollbar; moving to column 5 restarts the
+# timer without changing the copy-mode view.
+cp "$AFTER" "$HIDDEN"
+hover=$(printf '\033[<35;40;5M')
+$OUTER send-keys -l "$hover" || exit 1
+sleep 0.1
+capture "$VISIBLE"
+cmp -s "$HIDDEN" "$VISIBLE" && fail "scrollbar did not appear on hover"
+away=$(printf '\033[<35;5;5M')
+$OUTER send-keys -l "$away" || exit 1
+sleep 3.5
+capture "$AFTER"
+cmp -s "$HIDDEN" "$AFTER" || fail "scrollbar did not hide after hover"
+
+exit 0

regress/server-access.sh

@@ -0,0 +1,112 @@
+#!/bin/sh
+
+# Exercise the unprivileged server-access surface: user and group ACL entries,
+# read-only/writable transitions, listing, removal, implied addition, and
+# command errors. Actual connections from another UID require privileges and
+# deliberately do not form part of this test.
+
+PATH=/bin:/usr/bin
+TERM=screen
+export PATH TERM
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+TMUX="$TEST_TMUX -LtestA$$ -f/dev/null"
+OUT=$(mktemp) || exit 1
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$TMUX kill-server 2>/dev/null
+	rm -f "$OUT"
+}
+trap cleanup 0 1 15
+
+expect_fail()
+{
+	message=$1
+	shift
+	if $TMUX "$@" >"$OUT" 2>&1; then
+		fail "$message: command unexpectedly succeeded"
+	fi
+}
+
+assert_entry()
+{
+	entry=$1
+	$TMUX server-access -l >"$OUT" || exit 1
+	grep -Fxq "$entry" "$OUT" ||
+		fail "missing ACL entry '$entry'"
+}
+
+assert_no_entry()
+{
+	entry=$1
+	$TMUX server-access -l >"$OUT" || exit 1
+	if grep -Fxq "$entry" "$OUT"; then
+		fail "unexpected ACL entry '$entry'"
+	fi
+}
+
+owner_uid=$(id -u)
+owner_name=$(id -un)
+
+# nobody is the non-owner test identity. Derive its primary group rather than
+# assuming whether the system calls it nobody, nogroup, or something else.
+acl_user=nobody
+acl_group=$(id -gn "$acl_user" 2>/dev/null) ||
+	fail "the nobody account is unavailable"
+[ "$owner_name" != "$acl_user" ] || fail "test cannot run as nobody"
+
+$TMUX new-session -d -s access 'exec sleep 100' || exit 1
+
+# The owner is installed as writable at server startup (root is intentionally
+# omitted from display output).
+if [ "$owner_uid" != 0 ]; then
+	assert_entry "$owner_name (U,W)"
+fi
+
+# User ACL lifecycle, including duplicate and missing-entry errors.
+$TMUX server-access -a "$acl_user" || exit 1
+assert_entry "$acl_user (U,W)"
+expect_fail "duplicate user addition" server-access -a "$acl_user"
+$TMUX server-access -r "$acl_user" || exit 1
+assert_entry "$acl_user (U,R)"
+$TMUX server-access -w "$acl_user" || exit 1
+assert_entry "$acl_user (U,W)"
+$TMUX server-access -d "$acl_user" || exit 1
+assert_no_entry "$acl_user (U,W)"
+expect_fail "removing absent user" server-access -d "$acl_user"
+
+# -r and -w imply -a when an entry is absent.
+$TMUX server-access -r "$acl_user" || exit 1
+assert_entry "$acl_user (U,R)"
+$TMUX server-access -d "$acl_user" || exit 1
+
+# The same lifecycle for a group exercises the separate ACL key space.
+$TMUX server-access -g -a -r "$acl_group" || exit 1
+assert_entry "$acl_group (G,R)"
+$TMUX server-access -g -w "$acl_group" || exit 1
+assert_entry "$acl_group (G,W)"
+expect_fail "duplicate group addition" server-access -g -a "$acl_group"
+$TMUX server-access -g -d "$acl_group" || exit 1
+assert_no_entry "$acl_group (G,W)"
+expect_fail "removing absent group" server-access -g -d "$acl_group"
+
+# Parser and lookup errors, plus the immutable owner/root entries.
+expect_fail "missing ACL subject" server-access -a
+expect_fail "unknown user" server-access -a "tmux-no-user-$$"
+expect_fail "unknown group" server-access -g -a "tmux-no-group-$$"
+expect_fail "conflicting add/delete" server-access -a -d "$acl_user"
+expect_fail "conflicting read/write" server-access -r -w "$acl_user"
+expect_fail "changing server owner" server-access -r "$owner_name"
+if [ "$owner_name" != root ]; then
+	expect_fail "changing root access" server-access -a root
+fi
+
+$TMUX has-session -t access || fail "server exited during ACL updates"
+exit 0

regress/switch-mode.sh

@@ -0,0 +1,203 @@
+#!/bin/sh
+
+# Exercise switch-mode's session and window lists with a real attached client:
+# fuzzy filtering, movement and selection, the default and custom commands,
+# no-match cancellation, resize, zoom restoration, and -k mode teardown.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+DIR=$(mktemp -d) || exit 1
+TMUX_TMPDIR=$DIR
+export TMUX_TMPDIR
+INNER="$TEST_TMUX -LtestI$$ -f/dev/null"
+OUTER="$TEST_TMUX -LtestO$$ -f/dev/null"
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$OUTER kill-server 2>/dev/null
+	$INNER kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+capture()
+{
+	$OUTER capture-pane -p -t outer:0.0 2>/dev/null
+}
+
+wait_capture()
+{
+	marker=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		captured=$(capture)
+		printf '%s\n' "$captured" | grep -Fq "$marker" && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "timed out waiting for '$marker'"
+}
+
+wait_count()
+{
+	marker=$1
+	want=$2
+	i=0
+	while [ "$i" -lt 50 ]; do
+		captured=$(capture)
+		count=$(printf '%s\n' "$captured" | grep -Fc "$marker")
+		[ "$count" -eq "$want" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "found $count '$marker' rows, expected $want"
+}
+
+wait_format()
+{
+	target=$1
+	format=$2
+	want=$3
+	i=0
+	while [ "$i" -lt 50 ]; do
+		got=$($INNER display-message -p -t "$target" "$format" \
+		    2>/dev/null)
+		[ "$got" = "$want" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "$target format $format is '$got', expected '$want'"
+}
+
+wait_client_session()
+{
+	want=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		got=$($INNER list-clients -F '#{client_session}' 2>/dev/null)
+		[ "$got" = "$want" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "client session is '$got', expected '$want'"
+}
+
+# Three alphabetically ordered sessions. alpha:main has two panes so -Z can be
+# observed; the two pick-* windows make a deterministic two-row window filter.
+$INNER new-session -d -s alpha -n main -x60 -y15 'exec sleep 100' || exit 1
+$INNER split-window -d -h -t alpha:main 'exec sleep 100' || exit 1
+$INNER new-window -d -t alpha: -n pick-one 'exec sleep 100' || exit 1
+$INNER new-session -d -s bravo -n pick-two -x60 -y15 \
+	'exec sleep 100' || exit 1
+$INNER new-session -d -s charlie -n last -x60 -y15 \
+	'exec sleep 100' || exit 1
+$INNER set-option -g status off || exit 1
+$INNER set-option -g window-size manual || exit 1
+$INNER select-window -t alpha:main || exit 1
+
+$OUTER new-session -d -s outer -x60 -y15 "$INNER attach -t alpha" || exit 1
+$OUTER set-option -g status off || exit 1
+$OUTER set-option -g window-size manual || exit 1
+wait_client_session alpha
+
+# Session rows are sorted alpha, bravo, charlie. Up from the first row wraps to
+# charlie; Enter runs a custom command with the selected session target.
+$INNER set-option -g @picked '' || exit 1
+$INNER switch-mode -s -t alpha:main.0 -F 'SESSION #{session_name}' \
+	"set-option -g @picked '%%'" || exit 1
+wait_count 'SESSION ' 3
+$INNER send-keys -t alpha:main.0 Up Enter || exit 1
+wait_format alpha:main.0 '#{@picked}' '=charlie:'
+wait_format alpha:main.0 '#{pane_in_mode}' 0
+
+# Fuzzy filtering keeps only bravo for "brv". The default command switches the
+# real client to that session and closes the mode.
+$INNER switch-mode -s -t alpha:main.0 -F 'SESSION #{session_name}' || exit 1
+wait_count 'SESSION ' 3
+$INNER send-keys -t alpha:main.0 -l brv || exit 1
+wait_count 'SESSION ' 1
+printf '%s\n' "$captured" | grep -Fq 'SESSION bravo' ||
+	fail "fuzzy session filter did not select bravo"
+$INNER send-keys -t alpha:main.0 Enter || exit 1
+wait_client_session bravo
+client=$($INNER list-clients -F '#{client_name}')
+$INNER switch-client -c "$client" -t alpha || exit 1
+wait_client_session alpha
+
+# Window mode sees pick-one then pick-two for the "pick" filter. Down selects
+# the second row, and the custom command receives its window target.
+$INNER set-option -g @picked '' || exit 1
+$INNER switch-mode -w -t alpha:main.0 -F \
+	'WINDOW #{session_name}:#{window_name}' \
+	"set-option -g @picked '%%'" || exit 1
+wait_capture 'WINDOW '
+$INNER send-keys -t alpha:main.0 -l pick || exit 1
+wait_count 'WINDOW ' 2
+$INNER send-keys -t alpha:main.0 Down Enter || exit 1
+picked=$($INNER show-option -gv @picked)
+case "$picked" in
+=bravo:0.) ;;
+*) fail "window selection produced '$picked', expected '=bravo:0.'" ;;
+esac
+
+# Navigation with an empty result set must be harmless, and Escape cancels
+# without running the custom command.
+$INNER set-option -g @picked unchanged || exit 1
+$INNER switch-mode -s -t alpha:main.0 -F 'NONE #{session_name}' \
+	"set-option -g @picked '%%'" || exit 1
+wait_capture 'NONE '
+$INNER send-keys -t alpha:main.0 -l no-such-session || exit 1
+wait_count 'NONE ' 0
+$INNER send-keys -t alpha:main.0 Up Down PPage NPage Home End || exit 1
+wait_format alpha:main.0 '#{pane_mode}' switch-mode
+$INNER send-keys -t alpha:main.0 Escape || exit 1
+wait_format alpha:main.0 '#{pane_in_mode}' 0
+[ "$($INNER show-option -gv @picked)" = unchanged ] ||
+	fail "cancelled switch-mode ran its command"
+
+# -Z temporarily zooms an unzoomed window. Resizing while the mode is open
+# rebuilds and redraws it; exiting restores the original unzoomed state.
+$INNER switch-mode -Zs -t alpha:main.0 -F 'RESIZE #{session_name}' || exit 1
+wait_capture 'RESIZE alpha'
+wait_format alpha:main.0 '#{window_zoomed_flag}' 1
+$INNER resize-window -t alpha:main -x50 -y12 || exit 1
+wait_format alpha:main.0 '#{window_width}x#{window_height}' 50x12
+wait_format alpha:main.0 '#{pane_mode}' switch-mode
+$INNER send-keys -t alpha:main.0 Escape || exit 1
+wait_format alpha:main.0 '#{window_zoomed_flag}' 0
+
+# If the window was already zoomed, leaving -Z mode must keep it zoomed.
+$INNER resize-pane -Z -t alpha:main.0 || exit 1
+$INNER switch-mode -Zs -t alpha:main.0 -F 'ZOOMED #{session_name}' || exit 1
+wait_capture 'ZOOMED alpha'
+$INNER send-keys -t alpha:main.0 Escape || exit 1
+wait_format alpha:main.0 '#{window_zoomed_flag}' 1
+$INNER resize-pane -Z -t alpha:main.0 || exit 1
+
+# -k uses the shared mode teardown flag. Put it on a disposable pane and make
+# sure exiting the mode removes that pane.
+kill_pane=$($INNER split-window -d -P -F '#{pane_id}' -t alpha:main \
+	'exec sleep 100') || exit 1
+$INNER switch-mode -ks -t "$kill_pane" -F 'KILL #{session_name}' || exit 1
+wait_format "$kill_pane" '#{pane_mode}' switch-mode
+$INNER send-keys -t "$kill_pane" Escape || exit 1
+i=0
+while [ "$i" -lt 50 ]; do
+	$INNER list-panes -s -t alpha -F '#{pane_id}' 2>/dev/null | \
+	    grep -q -x "$kill_pane" || break
+	sleep 0.1
+	i=$((i + 1))
+done
+[ "$i" -lt 50 ] || fail "switch-mode -k did not kill its pane"
+
+exit 0

regress/sync-output-atomic.sh

@@ -14,8 +14,8 @@ DIR=$(mktemp -d) || exit 1
 TMUX_TMPDIR=$DIR
 export TMUX_TMPDIR
 
-INNER="$TEST_TMUX -Lsync-output-inner-$$ -f/dev/null"
-OUTER="$TEST_TMUX -Lsync-output-outer-$$ -f/dev/null"
+INNER="$TEST_TMUX -Li$$ -f/dev/null"
+OUTER="$TEST_TMUX -Lo$$ -f/dev/null"
 CLIENT_BYTES=$DIR/client-bytes
 CONTROL=$DIR/control
 EMITTER=$DIR/emitter.pl
@@ -112,7 +112,7 @@ $INNER set-option -g window-size manual || exit 1
 $INNER set-option -as terminal-features '*:sync' || exit 1
 
 $OUTER new-session -d -s outer -x 80 -y 24 \
-    "$TEST_TMUX -Lsync-output-inner-$$ -f/dev/null attach-session -t inner" ||
+    "$TEST_TMUX -Li$$ -f/dev/null attach-session -t inner" ||
     exit 1
 $OUTER set-option -g status off || exit 1
 $OUTER set-option -g window-size manual || exit 1

regress/sync-output-cursor.sh

@@ -0,0 +1,160 @@
+#!/bin/sh
+
+# A synchronized update elsewhere in the pane must not hide a stationary
+# cursor while tmux waits for the end of the update.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+
+if [ "$#" -eq 0 ]; then
+	TEST_TMUX="$TEST_TMUX" sh "$0" pane || exit 1
+	TEST_TMUX="$TEST_TMUX" sh "$0" prompt || exit 1
+	exit 0
+fi
+case $1 in
+pane|prompt) MODE=$1 ;;
+*) echo "usage: $0 [pane|prompt]" >&2; exit 1 ;;
+esac
+
+DIR=$(mktemp -d) || exit 1
+TMUX_TMPDIR=$DIR
+export TMUX_TMPDIR
+
+INNER="$TEST_TMUX -Li$$ -f/dev/null"
+OUTER="$TEST_TMUX -Lo$$ -f/dev/null"
+CLIENT_BYTES=$DIR/client-bytes
+CONTROL=$DIR/control
+EMITTER=$DIR/emitter.pl
+ASSERT=$DIR/assert-cursor.pl
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$OUTER kill-server 2>/dev/null
+	$INNER kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+wait_for_client()
+{
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$INNER list-clients -F '#{client_termfeatures}' 2>/dev/null |
+		    grep -q 'sync' && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "sync-capable client did not attach"
+}
+
+cat >"$EMITTER" <<'PERL'
+use strict;
+use warnings;
+
+my $control = $ENV{CONTROL};
+(my $dir = $control) =~ s{/[^/]+$}{};
+
+# Draw a prompt and leave its cursor stationary on the last line.
+syswrite STDOUT, "\e[2J\e[HWorking .\e[24;1H> ";
+open my $ready, '>', "$dir/ready" or die "$dir/ready: $!\n";
+close $ready;
+while (!-e $control) {
+	select undef, undef, undef, 0.01;
+}
+
+# Deliberately split BSU, content, and ESU across pane reads. This mirrors an
+# animation producer which begins a frame before it has finished rendering it.
+for my $spinner (qw(| / - \\)) {
+	syswrite STDOUT, "\e[?2026h";
+	select undef, undef, undef, 0.05;
+	syswrite STDOUT, "\e[1;9H$spinner\e[24;3H";
+	select undef, undef, undef, 0.01;
+	syswrite STDOUT, "\e[?2026l";
+	select undef, undef, undef, 0.15;
+}
+select undef, undef, undef, 5;
+PERL
+
+cat >"$ASSERT" <<'PERL'
+use strict;
+use warnings;
+
+my $path = shift;
+open my $fh, '<:raw', $path or die "$path: $!\n";
+local $/;
+my $bytes = <$fh>;
+my ($bsu, $esu, $hide, $show) =
+    ("\e[?2026h", "\e[?2026l", "\e[?25l", "\e[?25h");
+my ($sync, $outside, $hides, $shows) = (0, 0, 0, 0);
+
+for (my $i = 0; $i < length($bytes);) {
+	if (substr($bytes, $i, length($bsu)) eq $bsu) {
+		$sync++;
+		$i += length($bsu);
+		next;
+	}
+	if (substr($bytes, $i, length($esu)) eq $esu) {
+		$sync-- if $sync;
+		$i += length($esu);
+		next;
+	}
+	if (substr($bytes, $i, length($hide)) eq $hide) {
+		$hides++;
+		$outside++ unless $sync;
+		$i += length($hide);
+		next;
+	}
+	if (substr($bytes, $i, length($show)) eq $show) {
+		$shows++;
+		$outside++ unless $sync;
+		$i += length($show);
+		next;
+	}
+	$i++;
+}
+
+printf "%s cursor hides: %d; cursor shows: %d; changes outside sync: %d\n",
+    $ENV{MODE}, $hides, $shows, $outside;
+die "stationary cursor changed outside synchronized output\n" if $outside;
+PERL
+
+$INNER new-session -d -s inner -x 80 -y 24 \
+    "CONTROL='$CONTROL' perl '$EMITTER'" || exit 1
+$INNER set-option -g status off || exit 1
+$INNER set-option -g window-size manual || exit 1
+$INNER set-option -as terminal-features '*:sync' || exit 1
+
+$OUTER new-session -d -s outer -x 80 -y 24 \
+    "$TEST_TMUX -Li$$ -f/dev/null attach-session -t inner" || exit 1
+$OUTER set-option -g status off || exit 1
+$OUTER set-option -g window-size manual || exit 1
+wait_for_client
+
+if [ "$MODE" = prompt ]; then
+	$OUTER send-keys -t outer:0.0 C-b : || exit 1
+	sleep 0.2
+fi
+
+i=0
+while [ "$i" -lt 50 ] && [ ! -e "$DIR/ready" ]; do
+	sleep 0.1
+	i=$((i + 1))
+done
+[ -e "$DIR/ready" ] || fail "application emitter did not become ready"
+
+$OUTER pipe-pane -O -t outer:0.0 "cat >'$CLIENT_BYTES'" || exit 1
+: >"$CONTROL"
+sleep 2
+$OUTER pipe-pane -t outer:0.0 || exit 1
+
+MODE=$MODE perl "$ASSERT" "$CLIENT_BYTES"

regress/targets-panes.sh

@@ -97,6 +97,10 @@ check "p:.{top-left}" "%0"
 check_ok select-pane -t p:0.%0
 check "p:0.+" "1" '#{pane_index}'	# next pane
 check "p:0.-" "3" '#{pane_index}'	# previous pane (wraps)
+check_fail "can't find pane: +0" "p:0.+0"
+check_fail "can't find pane: +foo" "p:0.+foo"
+check_fail "can't find pane: -0" "p:0.-0"
+check_fail "can't find pane: -foo" "p:0.-foo"
 
 # --- last pane (!) --------------------------------------------------------
 check_ok select-pane -t p:0.%2

regress/targets.sh

@@ -154,6 +154,13 @@ check "alpha:{previous}" "3"
 check "alpha:!" "2"		# last window
 check "alpha:{last}" "2"
 
+# Malformed relative offsets must fail rather than silently selecting the
+# current window.
+check_fail "can't find window: +0" "alpha:+0"
+check_fail "can't find window: +foo" "alpha:+foo"
+check_fail "can't find window: -0" "alpha:-0"
+check_fail "can't find window: -foo" "alpha:-foo"
+
 # --- combined and empty forms ---------------------------------------------
 #
 # Empty targets use the current pane from TMUX_PANE when there is no client.

regress/terminal-feature-utf8.sh

@@ -0,0 +1,58 @@
+#!/bin/sh
+
+# The utf8 terminal feature must mark an attached client as UTF-8 even when
+# neither its environment nor -u does so. It must also be reported by the
+# client terminal-feature format lookup.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+INNER="$TEST_TMUX -LtestI$$ -f/dev/null"
+OUTER="$TEST_TMUX -LtestO$$ -f/dev/null"
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$OUTER kill-server 2>/dev/null
+	$INNER kill-server 2>/dev/null
+}
+trap cleanup 0 1 15
+
+cleanup
+$INNER new-session -d -s inner -x40 -y10 'exec sleep 100' || exit 1
+$INNER set-option -g status off || exit 1
+
+# A clean C-locale environment avoids the ordinary UTF-8 detection paths.
+# -T utf8 is therefore solely responsible for setting client_utf8.
+client_command="env -i PATH=/bin:/usr/bin TERM=screen LC_ALL=C $TEST_TMUX -T utf8 -LtestI$$ -f/dev/null attach-session -t inner"
+$OUTER new-session -d -s outer -x40 -y10 "$client_command" || exit 1
+$OUTER set-option -g status off || exit 1
+
+i=0
+while [ "$i" -lt 50 ]; do
+	client=$($INNER list-clients -F '#{client_name}' 2>/dev/null)
+	utf8=$($INNER list-clients -F '#{client_utf8}' 2>/dev/null)
+	[ -n "$client" ] && [ "$utf8" = 1 ] && break
+	sleep 0.1
+	i=$((i + 1))
+done
+[ "$i" -lt 50 ] || fail "utf8 terminal feature did not set client_utf8"
+
+features=$($INNER list-clients -F '#{client_termfeatures}')
+case ",$features," in
+*,utf8,*) ;;
+*) fail "utf8 is missing from client_termfeatures: $features" ;;
+esac
+
+present=$($INNER display-message -c "$client" -p '#{I/f:utf8}')
+[ "$present" = 1 ] || fail "utf8 terminal feature lookup returned '$present'"
+
+exit 0

regress/tty-draw-line.sh

@@ -105,6 +105,21 @@ sleep 1
 CLIENT=$($TMUX2 list-clients -F '#{client_name}' | head -1)
 [ -n "$CLIENT" ] || fail "no inner client"
 
+# A variation selector which widens the previous character must use window
+# coordinates when checking visibility in a pane with a nonzero x offset.
+$TMUX2 set -s variation-selector-always-wide on || exit 1
+WINDOW=$($TMUX2 neww -dPF '#{window_id}' "exec sleep 100") || exit 1
+PANE=$($TMUX2 splitw -dhPF '#{pane_id}' -t "$WINDOW" \
+	"exec sleep 100") || exit 1
+$TMUX2 selectw -t "$WINDOW" || exit 1
+$TMUX2 respawnp -k -t "$PANE" \
+	"printf '\nA\342\234\217\357\270\217B'; exec sleep 100" || exit 1
+sleep 1
+$TMUX2 capturep -p -t "$PANE" >$TMP || exit 1
+EXPECTED=$(printf 'A\342\234\217\357\270\217B')
+check_line 2 "$EXPECTED"
+$TMUX2 killw -t "$WINDOW" || exit 1
+
 # Long line, then short line: default cells after cellsize must clear stale text.
 capture
 check_line 1 "abcdefghijklmnopqrst"

regress/window-ops.sh

@@ -8,7 +8,7 @@
 # This exercises:
 # - new-window placement: next free index, explicit index, index in use with
 #   and without -k, -a (after) and -b (before) insertion with shuffling, and
-#   -S selecting an existing window by name instead of creating;
+#   -S selecting an existing window by name or target instead of creating;
 # - move-window to a free index, to an occupied index with and without -k,
 #   -a insertion and -r renumbering (including base-index);
 # - renumber-windows closing gaps;
@@ -17,7 +17,8 @@
 #   unlink the last link without -k;
 # - swap-window within and between sessions, -d keeping the active window,
 #   and the grouped-sessions error;
-# - rotate-window -U/-D rotating pane positions;
+# - rotate-window -U/-D rotating pane positions, with and without preserving
+#   zoom using -Z;
 # - kill-window switching to the last (previously current) window, kill-window
 #   -a killing all other windows and the "-f only valid with -a" guard.
 #
@@ -139,6 +140,36 @@ check_ok new-window -S -t W: -n w3
 check_windows W '0:wB 1:w0 2:w1 3:wA 4:w2 5:w3 9:w9k'
 check_fmt 'W:' '#{window_index}:#{window_name}' '5:w3'
 
+# -S with a target-window that already exists selects it directly, ignoring
+# -n (with -d it does not switch).
+check_ok select-window -t W:0
+check_ok new-window -S -t W:9 -n ignored
+check_windows W '0:wB 1:w0 2:w1 3:wA 4:w2 5:w3 9:w9k'
+check_fmt 'W:' '#{window_index}:#{window_name}' '9:w9k'
+check_ok select-window -t W:0
+check_ok new-window -S -d -t W:9 -n ignored
+check_windows W '0:wB 1:w0 2:w1 3:wA 4:w2 5:w3 9:w9k'
+check_fmt 'W:' '#{window_index}:#{window_name}' '0:wB'
+
+# -S with a target-window that does not yet exist still creates it normally.
+check_ok new-window -S -t W:20 -n w20
+check_windows W '0:wB 1:w0 2:w1 3:wA 4:w2 5:w3 9:w9k 20:w20'
+check_fmt 'W:' '#{window_index}:#{window_name}' '20:w20'
+check_ok kill-window -t W:20
+
+# -S also works with a relative target-window (+N): selects the window at
+# that offset if it exists, or creates it there if not.
+check_ok select-window -t W:0
+check_ok new-window -S -t W:+1
+check_fmt 'W:' '#{window_index}:#{window_name}' '1:w0'
+check_windows W '0:wB 1:w0 2:w1 3:wA 4:w2 5:w3 9:w9k'
+
+check_ok select-window -t W:0
+check_ok new-window -S -t W:+6 -n rel6
+check_fmt 'W:' '#{window_index}:#{window_name}' '6:rel6'
+check_windows W '0:wB 1:w0 2:w1 3:wA 4:w2 5:w3 6:rel6 9:w9k'
+check_ok kill-window -t W:6
+
 # Clean up to a known arrangement.
 check_ok kill-window -t W:wB
 check_ok kill-window -t W:wA
@@ -306,6 +337,24 @@ check_fmt 'R:0' '#{pane_index}:#{pane_id}' "0:$p1"
 check_ok rotate-window -D -t R:0
 check_fmt 'R:0' '#{pane_index}:#{pane_id}' "0:$p0"
 
+# Rotation without -Z unzooms. With -Z it preserves zoom and transfers it to
+# the pane which arrives at the active position.
+layout=$($TMUX display-message -p -t R:0 '#{window_layout}')
+check_ok resize-pane -Z -t "$p0"
+check_ok rotate-window -U -t R:0
+check_fmt "$p1" '#{window_zoomed_flag}:#{pane_zoomed_flag}:#{pane_active}' \
+	'0:0:1'
+check_ok rotate-window -D -t R:0
+check_fmt 'R:0' '#{window_layout}' "$layout"
+
+check_ok resize-pane -Z -t "$p0"
+check_ok rotate-window -U -Z -t R:0
+check_fmt "$p1" '#{window_zoomed_flag}:#{pane_zoomed_flag}:#{pane_active}' \
+	'1:1:1'
+check_ok resize-pane -Z -t "$p1"
+check_ok rotate-window -D -t R:0
+check_fmt 'R:0' '#{window_layout}' "$layout"
+
 # ---------------------------------------------------------------------------
 # kill-window.
 

resize.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: resize.c,v 1.58 2026/07/17 08:37:29 nicm Exp $ */
+/* $OpenBSD: resize.c,v 1.59 2026/08/20 09:19:24 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -42,8 +42,8 @@ resize_fire_window_resized(struct window *w, u_int old_sx, u_int old_sy)
 void
 resize_window(struct window *w, u_int sx, u_int sy, int xpixel, int ypixel)
 {
-	u_int	old_sx = w->sx, old_sy = w->sy;
-	int	zoomed;
+	struct window_pane	*zwp;
+	u_int			 old_sx = w->sx, old_sy = w->sy;
 
 	/* Check size limits. */
 	if (sx < WINDOW_MINIMUM)
@@ -56,8 +56,8 @@ resize_window(struct window *w, u_int sx, u_int sy, int xpixel, int ypixel)
 		sy = WINDOW_MAXIMUM;
 
 	/* If the window is zoomed, unzoom. */
-	zoomed = w->flags & WINDOW_ZOOMED;
-	if (zoomed)
+	zwp = window_zoomed_pane(w);
+	if (zwp != NULL)
 		window_unzoom(w, 1);
 
 	/* Resize the layout first. */
@@ -73,8 +73,8 @@ resize_window(struct window *w, u_int sx, u_int sy, int xpixel, int ypixel)
 	    sx, sy, w->layout_root->g.sx, w->layout_root->g.sy);
 
 	/* Restore the window zoom state. */
-	if (zoomed)
-		window_zoom(w->active);
+	if (zwp != NULL && window_has_pane(w, zwp))
+		window_zoom(zwp);
 
 	tty_update_window_offset(w);
 	server_redraw_window(w);

screen-redraw.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: screen-redraw.c,v 1.157 2026/07/24 08:49:23 nicm Exp $ */
+/* $OpenBSD: screen-redraw.c,v 1.159 2026/09/09 08:31:42 nicm Exp $ */
 
 /*
  * Copyright (c) 2026 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -713,7 +713,7 @@ redraw_mark_pane_borders(struct redraw_build_ctx *bctx, struct window_pane *wp,
 	} else {
 		mark_right = (right <= (int)bctx->w->sx);
 		mark_bottom = (bottom <= (int)bctx->w->sy);
-		if (pane_status == PANE_STATUS_TOP)
+		if (pane_status == PANE_STATUS_TOP && bottom < (int)bctx->w->sy)
 			mark_bottom = 0;
 		else if (pane_status == PANE_STATUS_BOTTOM)
 			mark_top = 0;
@@ -1738,8 +1738,7 @@ redraw_draw(struct client *c, struct window_pane *wp, int flags)
 			else
 				loop->flags &= ~PANE_NEWSTATUS;
 
-			width = redraw_pane_status_width(&dctx, loop,
-			    &first);
+			width = redraw_pane_status_width(&dctx, loop, &first);
 			if (width == 0)
 				continue;
 
@@ -1770,7 +1769,7 @@ redraw_draw(struct client *c, struct window_pane *wp, int flags)
 			}
 		}
 	}
-	tty_sync_start(tty);
+	tty_sync_start(tty); /* end in server_client_reset_state */
 	tty_update_mode(tty, tty->mode & ~CURSOR_MODES, NULL);
 
 	if (wp != NULL)
@@ -1815,7 +1814,6 @@ redraw_draw(struct client *c, struct window_pane *wp, int flags)
 		c->overlay_draw(c, c->overlay_data);
 
 	tty_reset(tty);
-	tty_sync_end(tty);
 
 #ifdef ENABLE_SIXEL
 	if (wp != NULL)

screen-write.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: screen-write.c,v 1.286 2026/08/03 12:58:53 nicm Exp $ */
+/* $OpenBSD: screen-write.c,v 1.290 2026/08/24 15:05:26 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -305,12 +305,14 @@ screen_write_initctx(struct screen_write_ctx *ctx, struct tty_ctx *ttyctx,
 
 	if (~ctx->flags & SCREEN_WRITE_SYNC) {
 		/*
-		 * For the active pane or for an overlay (no pane), we want to
-		 * only use synchronized updates if requested (commands that
-		 * move the cursor); for other panes, always use it, since the
-		 * cursor will have to move.
+		 * For the active pane showing its base screen or for an
+		 * overlay (no pane), only use synchronized updates if
+		 * requested (commands that move the cursor); for other panes
+		 * or a pane in a mode, always use it, since the cursor will
+		 * have to move.
 		 */
-		if (ctx->wp != NULL && ctx->wp != ctx->wp->window->active)
+		if (ctx->wp != NULL && (ctx->wp != ctx->wp->window->active ||
+		    ctx->wp->screen != &ctx->wp->base))
 			ttyctx->flags |= TTY_CTX_SYNC;
 		else {
 			if (ctx->wp == NULL)
@@ -338,10 +340,18 @@ screen_write_make_list(struct screen *s)
 void
 screen_write_free_list(struct screen *s)
 {
-	u_int	y;
+	struct screen_write_cline	*cl;
+	struct screen_write_citem	*ci, *ci1;
+	u_int				 y;
 
-	for (y = 0; y < screen_size_y(s); y++)
-		free(s->write_list[y].data);
+	for (y = 0; y < screen_size_y(s); y++) {
+		cl = &s->write_list[y];
+		TAILQ_FOREACH_SAFE(ci, &cl->items, entry, ci1) {
+			TAILQ_REMOVE(&cl->items, ci, entry);
+			screen_write_free_citem(ci);
+		}
+		free(cl->data);
+	}
 	free(s->write_list);
 }
 
@@ -1059,6 +1069,19 @@ screen_write_stop_sync(struct window_pane *wp)
 	log_debug("%s: %%%u stopped sync mode", __func__, wp->id);
 }
 
+/* Flush pending output before clearing sync mode. */
+void
+screen_write_end_sync(struct screen_write_ctx *ctx)
+{
+	struct window_pane	*wp = ctx->wp;
+
+	if (wp == NULL)
+		return;
+	if (wp->base.mode & MODE_SYNC)
+		screen_write_collect_flush(ctx, 0, __func__);
+	screen_write_stop_sync(wp);
+}
+
 /* Cursor up by ny. */
 void
 screen_write_cursorup(struct screen_write_ctx *ctx, u_int ny)
@@ -2839,10 +2862,11 @@ screen_write_combine(struct screen_write_ctx *ctx, const struct grid_cell *gc)
 	struct grid		*gd = s->grid;
 	const struct utf8_data	*ud = &gc->data;
 	struct options		*oo = global_options;
-	u_int			 i, n, cx = s->cx, cy = s->cy, vis, yoff = 0;
+	u_int			 i, n, cx = s->cx, cy = s->cy, vis;
 	struct grid_cell	 last;
 	struct tty_ctx		 ttyctx;
 	int			 force_wide = 0, zero_width = 0;
+	int			 xoff = 0, yoff = 0;
 	struct visible_ranges	*r;
 
 	/* Ignore U+3164 HANGUL_FILLER entirely. */
@@ -2936,9 +2960,11 @@ screen_write_combine(struct screen_write_ctx *ctx, const struct grid_cell *gc)
 	 * obscured in the middle, only on left or right, but there could be an
 	 * empty range in the visible ranges so we add them all up.
 	 */
-	if (wp != NULL)
+	if (wp != NULL) {
+		xoff = wp->xoff;
 		yoff = wp->yoff;
-	r = window_visible_ranges(wp, cx - n, cy + yoff, n, NULL);
+	}
+	r = window_visible_ranges(wp, xoff + cx - n, cy + yoff, n, NULL);
 	for (i = 0, vis = 0; i < r->used; i++)
 		vis += r->ranges[i].nx;
 	if (vis < n) {

server-client.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: server-client.c,v 1.503 2026/08/17 07:56:56 nicm Exp $ */
+/* $OpenBSD: server-client.c,v 1.511 2026/09/08 10:20:08 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -45,6 +45,7 @@ static void	server_client_set_path(struct client *);
 static void	server_client_set_progress_bar(struct client *);
 static void	server_client_reset_state(struct client *);
 static void	server_client_update_latest(struct client *);
+static int	server_client_handle_dead_key(struct window_pane *, key_code);
 static void	server_client_dispatch(struct imsg *, void *);
 static int	server_client_dispatch_command(struct client *, struct imsg *);
 static int	server_client_dispatch_identify(struct client *, struct imsg *);
@@ -523,7 +524,10 @@ server_client_lost(struct client *c)
 	input_cancel_requests(c);
 
 	free(c->title);
+	free(c->path);
 	free((void *)c->cwd);
+	free(c->exit_session);
+	free(c->exit_message);
 
 	evtimer_del(&c->repeat_timer);
 	evtimer_del(&c->click_timer);
@@ -800,8 +804,7 @@ server_client_check_mouse_in_pane(struct window_pane *wp, int px, int py,
 	} else {
 		/* Try the pane borders. */
 		TAILQ_FOREACH(fwp, &w->panes, entry) {
-			if ((w->flags & WINDOW_ZOOMED) &&
-			    (~fwp->flags & PANE_ZOOMED))
+			if (!window_pane_is_visible(fwp))
 				continue;
 			if (window_pane_is_floating(fwp) &&
 			    window_pane_get_pane_lines(fwp) == PANE_LINES_NONE)
@@ -1388,6 +1391,21 @@ server_client_repeat_time(struct client *c, struct key_binding *bd)
 	return (repeat);
 }
 
+/* Handle a key press on a dead pane waiting for a key. */
+static int
+server_client_handle_dead_key(struct window_pane *wp, key_code key)
+{
+	if (wp == NULL ||
+	    (~wp->flags & PANE_EXITED) ||
+	    KEYC_IS_MOUSE(key) ||
+	    KEYC_IS_PASTE(key) ||
+	    options_get_number(wp->options, "remain-on-exit") != 3)
+		return (0);
+	options_set_number(wp->options, "remain-on-exit", 0);
+	server_destroy_pane(wp, 0);
+	return (1);
+}
+
 /*
  * Handle data key input from client. This owns and can modify the key event it
  * is given and is responsible for freeing it.
@@ -1473,6 +1491,18 @@ server_client_key_callback(struct cmdq_item *item, void *data)
 	    server_client_is_assume_paste(c))
 		goto paste_key;
 
+	/* Forward keys directly if this pane is capturing all keys. */
+	if (wp != NULL &&
+	    (wp->flags & PANE_CAPTUREALLKEYS) &&
+	    (~wp->flags & PANE_EXITED) &&
+	    !KEYC_IS_MOUSE(key) &&
+	    TAILQ_EMPTY(&wp->modes))
+		goto forward_key;
+
+	/* Focus events are not keys and cannot be bound. */
+	if (key == KEYC_FOCUS_IN || key == KEYC_FOCUS_OUT)
+		goto forward_key;
+
 	/*
 	 * Work out the current key table. If the pane is in a mode, use
 	 * the mode table instead of the default key table.
@@ -1637,15 +1667,8 @@ try_again:
 	}
 
 forward_key:
-	if (wp != NULL &&
-	    (wp->flags & PANE_EXITED) &&
-	    !KEYC_IS_MOUSE(key) &&
-	    !KEYC_IS_PASTE(key) &&
-	    options_get_number(wp->options, "remain-on-exit") == 3) {
-		options_set_number(wp->options, "remain-on-exit", 0);
-		server_destroy_pane(wp, 0);
+	if (server_client_handle_dead_key(wp, key))
 		goto out;
-	}
 	if (c->flags & CLIENT_READONLY)
 		goto out;
 	if (wp != NULL)
@@ -1733,9 +1756,9 @@ server_client_handle_key0(struct client *c, struct key_event *event,
 	}
 
 	/*
-	 * Key presses in overlay mode and the command prompt are a special
-	 * case. The queue might be blocked so they need to be processed
-	 * immediately rather than queued.
+	 * Key presses in overlay mode, for panes capturing all keys and in the
+	 * command prompt are a special case. The queue might be blocked so they
+	 * need to be processed immediately rather than queued.
 	 */
 	if (~c->flags & CLIENT_READONLY) {
 		if (c->message_string != NULL) {
@@ -1755,6 +1778,21 @@ server_client_handle_key0(struct client *c, struct key_event *event,
 		}
 
 		server_client_clear_overlay(c);
+
+		wp = s->curw->window->active;
+		if (wp != NULL &&
+		    (wp->flags & PANE_CAPTUREALLKEYS) &&
+		    TAILQ_EMPTY(&wp->modes) &&
+		    !KEYC_IS_MOUSE(event->key)) {
+			if (server_client_handle_dead_key(wp, event->key))
+				return (0);
+			if (~wp->flags & PANE_EXITED) {
+				window_pane_key(wp, c, s, s->curw, event->key,
+				    &event->m);
+				return (0);
+			}
+		}
+
 		if (server_client_handle_menu_key(c, event))
 			return (0);
 		if (c->prompt != NULL) {
@@ -2206,7 +2244,7 @@ server_client_reset_state(struct client *c)
 					cy += status_line_size(c);
 			}
 
-			if ((pane_mode & MODE_SYNC) || !cursor)
+			if (!cursor)
 				mode &= ~MODE_CURSOR;
 		}
 	} else if (c->overlay_mode == NULL || s == NULL)
@@ -2214,6 +2252,10 @@ server_client_reset_state(struct client *c)
 	if (~pane_mode & MODE_SYNC) {
 		log_debug("%s: cursor to %u,%u", __func__, cx, cy);
 		tty_cursor(tty, cx, cy);
+	} else {
+		mode &= ~CURSOR_MODES;
+		mode |= tty->mode & CURSOR_MODES;
+		s = NULL;
 	}
 
 	/*
@@ -2375,8 +2417,6 @@ server_client_check_exit(struct client *c, int force)
 		proc_send(c->peer, c->exit_msgtype, -1, name, strlen(name) + 1);
 		break;
 	}
-	free(c->exit_session);
-	free(c->exit_message);
 }
 
 /* Redraw timer callback. */
@@ -2452,7 +2492,7 @@ server_client_check_redraw(struct client *c)
 
 	/* Work out if a redraw is actually needed. */
 	needed = 0;
-	if (c->flags & CLIENT_ALLREDRAWFLAGS)
+	if (c->flags & (CLIENT_ALLREDRAWFLAGS|CLIENT_REDRAWSCROLLBARS))
 		needed = 1;
 	else if (server_client_any_pane_redraw(c))
 		needed = 1;
@@ -2478,8 +2518,14 @@ server_client_check_redraw(struct client *c)
 			log_debug("redraw timer started");
 			evtimer_add(&ev, &tv);
 		}
-		if (server_client_any_pane_redraw(c))
-			c->flags |= CLIENT_REDRAWWINDOW;
+		TAILQ_FOREACH(wp, &w->panes, entry) {
+			if (wp->flags & PANE_REDRAW) {
+				c->flags |= CLIENT_REDRAWWINDOW;
+				break;
+			}
+			if (wp->flags & PANE_REDRAWSCROLLBAR)
+				c->flags |= CLIENT_REDRAWSCROLLBARS;
+		}
 		return;
 	}
 
@@ -2498,7 +2544,8 @@ server_client_check_redraw(struct client *c)
 				log_debug("%s: redraw pane %%%u", __func__,
 				    wp->id);
 				redraw_pane(c, wp);
-			} else if (wp->flags & PANE_REDRAWSCROLLBAR) {
+			} else if ((wp->flags & PANE_REDRAWSCROLLBAR) ||
+			    (c->flags & CLIENT_REDRAWSCROLLBARS)) {
 				log_debug("%s: redraw scrollbar %%%u", __func__,
 				    wp->id);
 				redraw_pane_scrollbar(c, wp);
@@ -2528,7 +2575,8 @@ server_client_check_redraw(struct client *c)
 	 * All the redraw flags can now be cleared. Also record how many bytes
 	 * were written.
 	 */
-	c->flags &= ~(CLIENT_ALLREDRAWFLAGS|CLIENT_STATUSFORCE);
+	c->flags &= ~(CLIENT_ALLREDRAWFLAGS|CLIENT_REDRAWSCROLLBARS|
+	    CLIENT_STATUSFORCE);
 	c->redraw = EVBUFFER_LENGTH(tty->out);
 	log_debug("%s: redraw added %zu bytes", c->name, c->redraw);
 }
@@ -3036,6 +3084,8 @@ server_client_control_flags(struct client *c, const char *next)
 		return (CLIENT_CONTROL_NOOUTPUT);
 	if (strcmp(next, "wait-exit") == 0)
 		return (CLIENT_CONTROL_WAITEXIT);
+	if (strcmp(next, "new-layouts") == 0)
+		return (CLIENT_CONTROL_NEWLAYOUTS);
 	return (0);
 }
 
@@ -3102,6 +3152,8 @@ server_client_get_flags(struct client *c)
 		strlcat(s, "no-output,", sizeof s);
 	if (c->flags & CLIENT_CONTROL_WAITEXIT)
 		strlcat(s, "wait-exit,", sizeof s);
+	if (c->flags & CLIENT_CONTROL_NEWLAYOUTS)
+		strlcat(s, "new-layouts,", sizeof s);
 	if (c->flags & CLIENT_CONTROL_PAUSEAFTER) {
 		xsnprintf(tmp, sizeof tmp, "pause-after=%u,",
 		    c->pause_age / 1000);

server-fn.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: server-fn.c,v 1.149 2026/07/27 14:25:46 nicm Exp $ */
+/* $OpenBSD: server-fn.c,v 1.152 2026/09/03 19:12:36 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -226,10 +226,11 @@ server_kill_pane(struct window_pane *wp)
 		server_kill_window(w, 1);
 		recalculate_sizes();
 	} else {
-		server_unzoom_window(w);
+		window_push_zoom(w, 0, wp->flags & PANE_FLOATOVERZOOM);
 		server_client_remove_pane(wp);
 		layout_close_pane(wp);
 		window_remove_pane(w, wp);
+		window_pop_zoom(w);
 		server_redraw_window(w);
 	}
 }
@@ -378,9 +379,9 @@ server_destroy_pane(struct window_pane *wp, int notify)
 		wp->pipe_fd = -1;
 	}
 
-	remain_on_exit = options_get_number(wp->options, "remain-on-exit");
-	if (remain_on_exit != 0 && (~wp->flags & PANE_STATUSREADY))
+	if (~wp->flags & PANE_STATUSREADY)
 		return;
+	remain_on_exit = options_get_number(wp->options, "remain-on-exit");
 	switch (remain_on_exit) {
 	case 0:
 		break;
@@ -421,15 +422,17 @@ server_destroy_pane(struct window_pane *wp, int notify)
 	if (notify)
 		server_fire_pane_exit("pane-exited", wp);
 
-	server_unzoom_window(w);
+	window_push_zoom(w, 0, wp->flags & PANE_FLOATOVERZOOM);
 	server_client_remove_pane(wp);
 	layout_close_pane(wp);
 	window_remove_pane(w, wp);
 
 	if (TAILQ_EMPTY(&w->panes))
 		server_kill_window(w, 1);
-	else
+	else {
+		window_pop_zoom(w);
 		server_redraw_window(w);
+	}
 }
 
 static void
@@ -551,6 +554,7 @@ server_check_unattached(void)
 				continue;
 			break;
 		}
+		server_destroy_session(s);
 		session_destroy(s, 1, __func__);
 	}
 }

server.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: server.c,v 1.215 2026/08/03 10:07:57 nicm Exp $ */
+/* $OpenBSD: server.c,v 1.216 2026/08/18 07:24:49 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -129,6 +129,7 @@ server_create_socket(uint64_t flags, char **cause)
 		mask = umask(S_IXUSR|S_IRWXG|S_IRWXO);
 	if (bind(fd, (struct sockaddr *)&sa, sizeof sa) == -1) {
 		saved_errno = errno;
+		umask(mask);
 		close(fd);
 		errno = saved_errno;
 		goto fail;

sort.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: sort.c,v 1.9 2026/06/29 07:45:09 nicm Exp $ */
+/* $OpenBSD: sort.c,v 1.10 2026/08/25 07:23:30 nicm Exp $ */
 
 /*
  * Copyright (c) 2026 Dane Jensen <dhcjensen@gmail.com>
@@ -32,7 +32,7 @@ sort_qsort(void *l, u_int len, u_int size, int (*cmp)(const void *,
 	u_int	 i;
 	void	*tmp, **ll;
 
-	if (sort_crit->order == SORT_END)
+	if (len < 2 || sort_crit->order == SORT_END)
 		return;
 
 	if (sort_crit->order == SORT_ORDER) {

spawn.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: spawn.c,v 1.50 2026/07/23 09:38:27 nicm Exp $ */
+/* $OpenBSD: spawn.c,v 1.52 2026/08/20 09:19:24 nicm Exp $ */
 
 /*
  * Copyright (c) 2019 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -243,7 +243,7 @@ struct window_pane *
 spawn_pane(struct spawn_context *sc, char **cause)
 {
 	struct cmdq_item	 *item = sc->item;
-	struct client		 *c;
+	struct client		 *c, *loop;
 	struct session		 *s = sc->s;
 	struct session		 *ts;
 	struct window		 *w = sc->wl->window;
@@ -331,6 +331,20 @@ spawn_pane(struct spawn_context *sc, char **cause)
 			input_free(sc->wp0->ictx);
 			sc->wp0->ictx = NULL;
 		}
+
+		/*
+		 * The old buffer is gone and the new one starts empty, so
+		 * offsets into the old buffer no longer mean anything. Reset
+		 * them, and drop output control clients still had queued.
+		 */
+		sc->wp0->offset.used = 0;
+		sc->wp0->base_offset = 0;
+		sc->wp0->pipe_offset.used = 0;
+		TAILQ_FOREACH(loop, &clients, entry) {
+			if (loop->flags & CLIENT_CONTROL)
+				control_reset_pane(loop, sc->wp0);
+		}
+
 		new_wp = sc->wp0;
 		new_wp->flags &= ~(PANE_STATUSREADY|PANE_STATUSDRAWN);
 	} else {
@@ -346,6 +360,8 @@ spawn_pane(struct spawn_context *sc, char **cause)
 		}
 		if (sc->flags & SPAWN_FLOATING)
 			new_wp->layout_cell->flags |= LAYOUT_CELL_FLOATING;
+		if (sc->flags & SPAWN_FLOATOVERZOOM)
+			new_wp->flags |= PANE_FLOATOVERZOOM;
 
 		/*
 		 * If window currently zoomed, window_set_active_pane calls
@@ -731,10 +747,10 @@ spawn_editor(struct client *c, const char *buf, size_t len,
 	lg.sy = w->sy * 9 / 10;
 	lg.xoff = w->sx / 2 - lg.sx / 2;
 	lg.yoff = w->sy / 2 - lg.sy / 2;
-	window_push_modal_zoom(w);
+	window_push_zoom(w, 0, 1);
 	lc = layout_floating_pane(w, NULL, &lg);
 	if (lc == NULL) {
-		window_pop_modal_zoom(w);
+		window_pop_zoom(w);
 		spawn_editor_free(es);
 		return (NULL);
 	}
@@ -751,17 +767,18 @@ spawn_editor(struct client *c, const char *buf, size_t len,
 	sc.environ = env;
 	sc.idx = -1;
 	sc.cwd = _PATH_TMP;
-	sc.flags = SPAWN_FLOATING|SPAWN_MODAL;
+	sc.flags = SPAWN_FLOATING|SPAWN_MODAL|SPAWN_FLOATOVERZOOM;
 
 	wp = spawn_pane(&sc, &cause);
 	free(cmd);
 	environ_free(env);
 	if (wp == NULL) {
 		free(cause);
-		window_pop_modal_zoom(w);
+		window_pop_zoom(w);
 		spawn_editor_free(es);
 		return (NULL);
 	}
+	window_pop_zoom(w);
 	options_set_number(wp->options, "remain-on-exit", 0);
 	es->pid = wp->pid;
 	wp->editor = es;

tmux.1

@@ -1,4 +1,4 @@
-.\" $OpenBSD: tmux.1,v 1.1156 2026/08/17 14:47:41 nicm Exp $
+.\" $OpenBSD: tmux.1,v 1.1168 2026/09/09 07:03:39 nicm Exp $
 .\"
 .\" Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
 .\"
@@ -14,7 +14,7 @@
 .\" IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 .\" OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: August 17 2026 $
+.Dd $Mdocdate: September 9 2026 $
 .Dt TMUX 1
 .Os
 .Sh NAME
@@ -1116,6 +1116,8 @@ The flags are:
 .Bl -tag -width Ds
 .It ignore\-size
 the client does not affect the size of other clients
+.It new\-layouts
+use the new layout string format
 .It no\-detach\-on\-destroy
 do not detach the client when the session it is attached to is destroyed if
 there are any other sessions
@@ -2208,14 +2210,14 @@ Move to the end of the next word.
 .Xc
 Same as
 .Ic next\-word
-but use a space alone as the word separator.
+but treat all non-whitespace characters as part of a word.
 .It Xo
 .Ic next\-space\-end
 (vi: E)
 .Xc
 Same as
 .Ic next\-word\-end
-but use a space alone as the word separator.
+but treat all non-whitespace characters as part of a word.
 .It Xo
 .Ic other\-end
 (vi: o)
@@ -2289,7 +2291,7 @@ Move to the previous word.
 .Xc
 Same as
 .Ic previous\-word
-but use a space alone as the word separator.
+but treat all non-whitespace characters as part of a word.
 .It Xo
 .Ic rectangle\-on
 .Xc
@@ -2574,8 +2576,8 @@ Word separators can be customized with the
 session option.
 Next word moves to the start of the next word, next word end to the end of the
 next word and previous word to the start of the previous word.
-The three next and previous space keys work similarly but use a space alone as
-the word separator.
+The three next and previous space keys work similarly but treat all
+non-whitespace characters as part of a word.
 Setting
 .Em word\-separators
 to the empty string makes next/previous word equivalent to next/previous space.
@@ -2699,8 +2701,8 @@ For example:
 .Bd -literal -offset indent
 $ tmux list\-windows
 0: ksh [159x48]
-    layout: bb62,159x48,0,0{79x48,0,0,79x48,80,0}
-$ tmux select\-layout \[aq]bb62,159x48,0,0{79x48,0,0,79x48,80,0}\[aq]
+    layout: {"V":2,"L":{"t":"h","w":159,"h":48,"x":0,"y":0,"c":[{"t":"p","w":79,"h":48,"x":0,"y":0,"l":0,"i":0,"I":"%0"},{"t":"p","w":79,"h":48,"x":80,"y":0,"a":true,"i":1,"I":"%2"}]}}
+$ tmux select\-layout \[aq]{"V":2,"L":{"t":"h","w":159,"h":48,"x":0,"y":0,"c":[{"t":"p","w":79,"h":48,"x":0,"y":0,"l":0,"i":0,"I":"%0"},{"t":"p","w":79,"h":48,"x":80,"y":0,"a":true,"i":1,"I":"%2"}]}}\[aq]
 .Ed
 .Pp
 .Nm
@@ -2788,7 +2790,7 @@ The pane must not already be floating or hidden, and the window must not
 be zoomed.
 .Tg capturep
 .It Xo Ic capture\-pane
-.Op Fl aeFHLpPRqCJMN
+.Op Fl aeFHILpPRqCJMN
 .Op Fl b Ar buffer\-name
 .Op Fl E Ar end\-line
 .Op Fl S Ar start\-line
@@ -2830,6 +2832,8 @@ captures only any output that the pane has received that is the beginning of an
 as-yet incomplete escape sequence.
 .Fl L
 includes the line number at the start of each line and
+.Fl I
+includes the time each line entered the history, or zero if not available.
 .Fl F
 includes the flags (where
 .Ql -
@@ -3590,13 +3594,20 @@ represents the window to be created; if the target already exists an error is
 shown, unless the
 .Fl k
 flag is used, in which case it is destroyed.
+.Ar window\-name
+is the name given to the new window, if any.
+.Pp
 If
 .Fl S
-is given and a window named
-.Ar window\-name
-already exists, it is selected (unless
+is given, an existing window is selected instead of creating a new one
+(unless
 .Fl d
-is also given in which case the command does nothing).
+is also given in which case the command does nothing):
+.Ar target\-window
+is preferred if it already identifies an existing window; otherwise a
+window named
+.Ar window\-name
+is selected if one exists.
 .Pp
 .Ar shell\-command
 is the command to execute.
@@ -3644,7 +3655,7 @@ but a different format may be specified with
 .Fl F .
 .Tg newp
 .It Xo Ic new\-pane
-.Op Fl bCdefhIkLMOPvWZ
+.Op Fl AbCdefhIkKLMOPvWZ
 .Op Fl B Ar border\-lines
 .Op Fl c Ar start\-directory
 .Op Fl e Ar environment
@@ -3693,14 +3704,17 @@ sets the pane border lines for floating panes; see
 .Fl M
 may be used when bound to a mouse drag key; the new floating pane is resized to
 follow the mouse drag.
-It has no effect with
-.Fl L .
+.Fl A
+creates a floating pane which remains visible above a zoomed pane.
 .Fl O
 creates a modal pane.
 A modal pane is always the active pane and prevents interaction with any other
 panes while it is active.
 A window can only have one modal pane and it must be a floating pane.
 With
+.Fl K ,
+all keys, including the prefix key, are passed directly to the modal pane.
+With
 .Fl C ,
 the modal pane is closed when the mouse is clicked outside it.
 .Pp
@@ -4751,6 +4765,15 @@ for backspace.
 Set the number of buffers; as new buffers are added to the top of the stack,
 old ones are removed from the bottom if necessary to maintain this maximum
 length.
+.It Xo Ic clear\-on\-attach
+.Op Ic on | off
+.Xc
+When enabled (the default), the client terminal switches to the alternate
+screen and clears it when a client is attached.
+When disabled,
+.Nm
+does not enter the alternate screen; instead the existing terminal content is
+scrolled into the scrollback buffer so it remains accessible.
 .It Xo Ic command\-alias[]
 .Ar name=value
 .Xc
@@ -5101,6 +5124,8 @@ Supports
 title setting.
 .It usstyle
 Allows underscore style and colour to be set.
+.It utf8
+Supports UTF\-8 output.
 .El
 .It Ic terminal\-overrides[] Ar string
 Allow terminal descriptions read using
@@ -5635,6 +5660,11 @@ If set to both, a bell and a message are produced.
 Sets the session's conception of what characters are considered word
 separators, for the purposes of the next and previous word commands in
 copy mode.
+A space in
+.Ar string
+matches any character with the Unicode
+.Em White_Space
+property.
 .El
 .Pp
 Available window options are:
@@ -7304,7 +7334,10 @@ The following variables are available, where appropriate:
 .It Li "cursor_very_visible" Ta "" Ta "1 if the cursor is in very visible mode"
 .It Li "cursor_x" Ta "" Ta "Cursor X position in pane"
 .It Li "cursor_y" Ta "" Ta "Cursor Y position in pane"
+.It Li "history_added" Ta "" Ta "Number of lines scrolled into pane history"
 .It Li "history_bytes" Ta "" Ta "Number of bytes in window history"
+.It Li "history_collected" Ta "" Ta "Number of oldest pane history lines discarded at the history limit"
+.It Li "history_generation" Ta "" Ta "Generation incremented when pane history is cleared or reflowed"
 .It Li "history_limit" Ta "" Ta "Maximum window history lines"
 .It Li "history_size" Ta "" Ta "Size of history in lines"
 .It Li "hook" Ta "" Ta "Name of running hook, if any"
@@ -7403,6 +7436,7 @@ The following variables are available, where appropriate:
 .It Li "pane_marked_set" Ta "" Ta "1 if a marked pane is set"
 .It Li "pane_modal_flag" Ta "" Ta "1 if pane is modal"
 .It Li "pane_mode" Ta "" Ta "Name of pane mode, if any"
+.It Li "pane_output_generation" Ta "" Ta "Generation incremented when pane output is processed"
 .It Li "pane_path" Ta "" Ta "Path of pane (can be set by application)"
 .It Li "pane_pid" Ta "" Ta "PID of first process in pane"
 .It Li "pane_pipe" Ta "" Ta "1 if pane is being piped"
@@ -8247,7 +8281,7 @@ The following keys are available in menus:
 .El
 .Tg display
 .It Xo Ic display\-message
-.Op Fl aCIlNpv
+.Op Fl aCIjlNpv
 .Op Fl c Ar target\-client
 .Op Fl d Ar delay
 .Op Fl t Ar target\-pane
@@ -8287,6 +8321,12 @@ if
 .Fl t
 is given, otherwise the active pane.
 .Pp
+If
+.Fl j
+is given,
+.Ar message
+is parsed as JSON and printed.
+.Pp
 .Fl v
 prints verbose logging as the format is parsed and
 .Fl a
@@ -9032,7 +9072,7 @@ and flags (currently not used).
 For example:
 .Bd -literal -offset indent
 %begin 1363006971 2 1
-0: ksh* (1 panes) [80x24] [layout b25f,80x24,0,0,2] @2 (active)
+0: ksh* (1 panes) [80x24] [layout {"V":2,"L":{"t":"p","w":80,"h":24,"x":0,"y":0,"a":true,"i":0,"I":"%2"}}] @2 (active)
 %end 1363006971 2 1
 .Ed
 .Pp
@@ -9093,10 +9133,15 @@ The layout of a window with ID
 .Ar window\-id
 changed.
 The new layout is
-.Ar window\-layout .
-The window's visible layout is
-.Ar window\-visible\-layout
-and the window flags are
+.Ar window\-layout
+and the window's visible layout is
+.Ar window\-visible\-layout .
+If the
+.Ar new\-layouts
+flag is set, both layout fields use the new format string; see
+.Ic refresh\-client
+.Fl f .
+The window flags are
 .Ar window\-flags .
 .It Ic %message Ar message
 A message sent with the

tmux.h

@@ -1,4 +1,4 @@
-/* $OpenBSD: tmux.h,v 1.1424 2026/08/17 14:47:41 nicm Exp $ */
+/* $OpenBSD: tmux.h,v 1.1438 2026/09/09 08:30:05 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -60,6 +60,7 @@ struct input_ctx;
 struct input_request;
 struct input_requests;
 struct job;
+struct json_node;
 struct menu_data;
 struct mode_tree_data;
 struct mouse_event;
@@ -483,6 +484,7 @@ enum tty_code_code {
 	TTYC_ICH1,
 	TTYC_IL,
 	TTYC_IL1,
+	TTYC_IND,
 	TTYC_INDN,
 	TTYC_INVIS,
 	TTYC_KCBT,
@@ -1335,6 +1337,8 @@ struct window_pane {
 #define PANE_CMDRUNNING 0x20000
 #define PANE_ACTIVITY 0x40000
 #define PANE_CLOSEONCLICK 0x80000
+#define PANE_CAPTUREALLKEYS 0x100000
+#define PANE_FLOATOVERZOOM 0x200000
 
 	bitstr_t	*sync_dirty;
 	u_int		 sync_dirty_size;
@@ -1354,9 +1358,10 @@ struct window_pane {
 	char		 tty[TTY_NAME_MAX];
 	int		 status;
 	struct timeval	 dead_time;
-	struct cmdq_item *wait_item;	/* new-pane -W: waiting for pane exit */
+	struct cmdq_item *wait_item;
 	struct spawn_editor_state *editor;
 
+	uint64_t	 output_generation;
 	time_t		 last_output_time;
 	time_t		 last_prompt_time;
 	time_t		 cmd_start_time;
@@ -1441,6 +1446,7 @@ struct window {
 	struct window_pane	*active;
 	struct window_pane	*modal;
 	struct window_pane	*modal_last;
+	struct window_pane	*was_zoomed;
 	struct window_panes 	 last_panes;
 	struct window_panes      z_index;
 	struct window_panes	 panes;
@@ -1483,7 +1489,6 @@ struct window {
 #define WINDOW_ZOOMED 0x8
 #define WINDOW_WASZOOMED 0x10
 #define WINDOW_RESIZE 0x20
-#define WINDOW_WASMODALZOOMED 0x40
 #define WINDOW_ALERTFLAGS (WINDOW_BELL|WINDOW_ACTIVITY|WINDOW_SILENCE)
 
 	int			 alerts_queued;
@@ -1811,8 +1816,9 @@ struct tty {
 #define TTY_WAITFG 0x2000
 #define TTY_WAITBG 0x4000
 #define TTY_BRACKETPASTE 0x8000
+#define TTY_HAVESYNC 0x10000
 #define TTY_ALL_REQUEST_FLAGS \
-	(TTY_HAVEDA|TTY_HAVEDA2|TTY_HAVEXDA)
+	(TTY_HAVEDA|TTY_HAVEDA2|TTY_HAVEXDA|TTY_HAVESYNC)
 	int		 flags;
 
 	struct tty_term	*term;
@@ -2287,15 +2293,16 @@ struct client {
 #define CLIENT_STARTSERVER 0x10000000
 #define CLIENT_REDRAWMENU 0x20000000
 #define CLIENT_NOFORK 0x40000000
-/* 0x80000000ULL unused */
+#define CLIENT_REDRAWSCROLLBARS 0x80000000ULL
 #define CLIENT_CONTROL_PAUSEAFTER 0x100000000ULL
 #define CLIENT_CONTROL_WAITEXIT 0x200000000ULL
 #define CLIENT_WINDOWSIZECHANGED 0x400000000ULL
-/* 0x800000000ULL unused */
+#define CLIENT_CONTROL_NEWLAYOUTS 0x800000000ULL
 #define CLIENT_BRACKETPASTING 0x1000000000ULL
 #define CLIENT_ASSUMEPASTING 0x2000000000ULL
 #define CLIENT_WRITE_ACK 0x4000000000ULL
 #define CLIENT_NO_DETACH_ON_DESTROY 0x8000000000ULL
+#define CLIENT_CONTROL_DISCARD 0x1000000000ULL
 #define CLIENT_ALLREDRAWFLAGS		\
 	(CLIENT_REDRAWWINDOW|		\
 	 CLIENT_REDRAWSTATUS|		\
@@ -2533,6 +2540,7 @@ struct spawn_context {
 #define SPAWN_HORIZONTAL 0x200
 #define SPAWN_SPLIT 0x400
 #define SPAWN_MODAL 0x800
+#define SPAWN_FLOATOVERZOOM 0x1000
 };
 
 /* Paste buffer. */
@@ -3600,6 +3608,7 @@ void	 screen_write_mode_set(struct screen_write_ctx *, int);
 void	 screen_write_mode_clear(struct screen_write_ctx *, int);
 void	 screen_write_start_sync(struct window_pane *);
 void	 screen_write_stop_sync(struct window_pane *);
+void	 screen_write_end_sync(struct screen_write_ctx *);
 void	 screen_write_clear_dirty(struct window_pane *);
 void	 screen_write_cursorup(struct screen_write_ctx *, u_int);
 void	 screen_write_cursordown(struct screen_write_ctx *, u_int);
@@ -3729,8 +3738,8 @@ void		 window_resize(struct window *, u_int, u_int, int, int);
 void		 window_pane_send_resize(struct window_pane *, u_int, u_int);
 int		 window_zoom(struct window_pane *);
 int		 window_unzoom(struct window *, int);
-void		 window_push_modal_zoom(struct window *);
-int		 window_pop_modal_zoom(struct window *);
+int		 window_active_pane_is_over_zoom(struct window *);
+struct window_pane *window_zoomed_pane(struct window *);
 int		 window_push_zoom(struct window *, int, int);
 int		 window_pop_zoom(struct window *);
 void		 window_lost_pane(struct window *, struct window_pane *);
@@ -3742,6 +3751,7 @@ struct window_pane *window_pane_previous_by_number(struct window *,
 			struct window_pane *, u_int);
 int		 window_pane_index(struct window_pane *, u_int *);
 int		 window_pane_zindex(struct window_pane *, u_int *);
+int		 window_pane_last_index(struct window_pane *, u_int *);
 u_int		 window_count_panes(struct window *, int);
 void		 window_destroy_panes(struct window *);
 struct window_pane *window_pane_find_by_id_str(const char *);
@@ -3841,7 +3851,7 @@ struct visible_ranges *window_visible_ranges(struct window_pane *, int, int,
 		     u_int, struct visible_ranges *);
 
 /* layout.c */
-u_int		 layout_count_cells(struct layout_cell *);
+u_int		 layout_count_cells(struct layout_cell *, int);
 struct layout_cell *layout_create_cell(struct layout_cell *);
 void		 layout_free_cell(struct layout_cell *, int);
 void		 layout_print_cell(struct layout_cell *, const char *, u_int);
@@ -3853,8 +3863,8 @@ struct layout_cell *layout_search_by_border(struct layout_cell *, u_int, u_int);
 void		 layout_set_size(struct layout_cell *, u_int, u_int, int, int);
 void		 layout_make_leaf(struct layout_cell *, struct window_pane *);
 void		 layout_make_node(struct layout_cell *, enum layout_type);
-void		 layout_fix_zindexes(struct window *, struct layout_cell *);
 int		 layout_cell_is_tiled(struct layout_cell *);
+int		 layout_cell_has_tiled_child(struct layout_cell *);
 int		 layout_add_horizontal_border(struct layout_cell *,
 		     struct layout_cell *, int);
 void		 layout_fix_offsets(struct window *);
@@ -3905,7 +3915,8 @@ int		 layout_remove_tile(struct window *, struct layout_cell *);
 int		 layout_insert_tile(struct window *, struct layout_cell *);
 
 /* layout-custom.c */
-char		*layout_dump(struct window *, struct layout_cell *);
+#define LAYOUT_CUSTOM_OLD_FORMAT 0x1
+char		*layout_dump(struct window *, struct layout_cell *, int);
 int		 layout_parse(struct window *, const char *, char **);
 
 /* layout-set.c */
@@ -4035,6 +4046,7 @@ void	control_set_pane_on(struct client *, struct window_pane *);
 void	control_set_pane_off(struct client *, struct window_pane *);
 void	control_continue_pane(struct client *, struct window_pane *);
 void	control_pause_pane(struct client *, struct window_pane *);
+void	control_reset_pane(struct client *, struct window_pane *);
 void	control_set_window_size(struct client *, u_int, u_int, u_int);
 int	control_get_window_size(struct client *, u_int, u_int *, u_int *);
 void	control_clear_window_size(struct client *, u_int);
@@ -4099,6 +4111,7 @@ void		 session_update_history(struct session *);
 /* utf8.c */
 enum utf8_state	 utf8_towc (const struct utf8_data *, wchar_t *);
 enum utf8_state	 utf8_fromwc(wchar_t wc, struct utf8_data *);
+int		 utf8_has_whitespace(const struct utf8_data *);
 void		 utf8_update_width_cache(void);
 utf8_char	 utf8_build_one(u_char);
 enum utf8_state	 utf8_from_data(const struct utf8_data *, utf8_char *);
@@ -4263,4 +4276,29 @@ struct hyperlinks	*hyperlinks_copy(struct hyperlinks *);
 void			 hyperlinks_reset(struct hyperlinks *);
 void			 hyperlinks_free(struct hyperlinks *);
 
+/* json.c */
+struct json_node	*json_parse(const char *, char **);
+void			 json_destroy_node(struct json_node *);
+char			*json_to_string(struct json_node *);
+struct json_node	*json_find(struct json_node *, const char *);
+struct json_node	*json_array_first(struct json_node *);
+struct json_node	*json_array_next(struct json_node *);
+int			 json_get_string(struct json_node *, const char **);
+int			 json_get_number(struct json_node *, int64_t *);
+int			 json_get_boolean(struct json_node *, int *);
+int			 json_get_object(struct json_node *,
+			     struct json_node **);
+int			 json_get_array(struct json_node *,
+			     struct json_node **);
+int			 json_find_string(struct json_node *, const char *,
+			     const char **, char **);
+int			 json_find_number(struct json_node *, const char *,
+			     int64_t *, char **);
+int			 json_find_boolean(struct json_node *, const char *,
+			     int *, char **);
+int			 json_find_object(struct json_node *, const char *,
+			     struct json_node **, char **);
+int			 json_find_array(struct json_node *, const char *,
+			     struct json_node **, char **);
+
 #endif /* TMUX_H */

tty-features.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: tty-features.c,v 1.42 2026/08/17 14:47:41 nicm Exp $ */
+/* $OpenBSD: tty-features.c,v 1.43 2026/08/31 12:41:03 kirill Exp $ */
 
 /*
  * Copyright (c) 2020 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -368,6 +368,13 @@ static const struct tty_feature tty_feature_progressbar = {
 	0
 };
 
+/* Terminal supports UTF-8. */
+static const struct tty_feature tty_feature_utf8 = {
+	"utf8",
+	NULL,
+	0
+};
+
 /* Available terminal features. */
 static const struct tty_feature *const tty_features[] = {
 	&tty_feature_256,
@@ -390,7 +397,8 @@ static const struct tty_feature *const tty_features[] = {
 	&tty_feature_strikethrough,
 	&tty_feature_sync,
 	&tty_feature_title,
-	&tty_feature_usstyle
+	&tty_feature_usstyle,
+	&tty_feature_utf8
 };
 
 /* Parse features for client. */
@@ -473,6 +481,9 @@ tty_feature_present(struct tty_term *term, const char *name)
 	u_int				 i;
 	char				*copy;
 
+	if (strcmp(name, "utf8") == 0)
+		return ((term->tty->client->flags & CLIENT_UTF8) != 0);
+
 	for (i = 0; i < nitems(tty_features); i++) {
 		tf = tty_features[i];
 		if (strcmp(tf->name, name) == 0) {
@@ -486,7 +497,8 @@ tty_feature_present(struct tty_term *term, const char *name)
 	 * We don't just have the feature flag set. Check if the capabilities
 	 * supported by the client are actual set instead.
 	 */
-	if (tf == NULL || strcmp(name, "ignorefkeys") == 0)
+	if (tf == NULL || tf->capabilities == NULL ||
+	    strcmp(name, "ignorefkeys") == 0)
 		return (0);
 	if (tf->flags != 0 && (term->flags & tf->flags) != tf->flags)
 		return (0);
@@ -534,6 +546,8 @@ tty_apply_features(struct tty_term *term)
 			}
 		}
 		term->flags |= tf->flags;
+		if (tf == &tty_feature_utf8)
+			c->flags |= CLIENT_UTF8;
 	}
 	if ((term->applied_features|feat) == term->applied_features)
 		return (0);

tty-keys.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: tty-keys.c,v 1.213 2026/08/17 14:47:41 nicm Exp $ */
+/* $OpenBSD: tty-keys.c,v 1.214 2026/08/18 09:01:20 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -59,6 +59,7 @@ static int	tty_keys_device_attributes2(struct tty *, const char *, size_t,
 		    size_t *);
 static int	tty_keys_extended_device_attributes(struct tty *, const char *,
 		    size_t, size_t *);
+static int	tty_keys_sync(struct tty *, const char *, size_t, size_t *);
 static int	tty_keys_palette(struct tty *, const char *, size_t, size_t *);
 
 /* A key tree entry. */
@@ -771,6 +772,17 @@ tty_keys_next(struct tty *tty)
 		goto partial_key;
 	}
 
+	/* Is this a synchronized update mode response? */
+	switch (tty_keys_sync(tty, buf, len, &size)) {
+	case 0:		/* yes */
+		key = KEYC_UNKNOWN;
+		goto complete_key;
+	case -1:	/* no, or not valid */
+		break;
+	case 1:		/* partial */
+		goto partial_key;
+	}
+
 	/* Is this a primary device attributes response? */
 	switch (tty_keys_device_attributes(tty, buf, len, &size)) {
 	case 0:		/* yes */
@@ -1521,6 +1533,54 @@ tty_keys_device_attributes(struct tty *tty, const char *buf, size_t len,
 	return (0);
 }
 
+/*
+ * Handle a synchronized update mode response. Returns 0 for success, -1 for
+ * failure, 1 for partial.
+ */
+static int
+tty_keys_sync(struct tty *tty, const char *buf, size_t len, size_t *size)
+{
+	struct client		*c = tty->client;
+	static const char	 prefix[] = "\033[?2026;";
+	size_t			 i;
+	int			 status;
+
+	*size = 0;
+	if (tty->flags & TTY_HAVESYNC)
+		return (-1);
+
+	/* The response is always \033[?2026;Ps$y. */
+	for (i = 0; i < (sizeof prefix) - 1; i++) {
+		if (i == len)
+			return (1);
+		if (buf[i] != prefix[i])
+			return (-1);
+	}
+	if (i == len)
+		return (1);
+	if (buf[i] < '0' || buf[i] > '4')
+		return (-1);
+	status = buf[i++] - '0';
+	if (i == len)
+		return (1);
+	if (buf[i++] != '$')
+		return (-1);
+	if (i == len)
+		return (1);
+	if (buf[i++] != 'y')
+		return (-1);
+	*size = i;
+
+	if (status == 1 || status == 2 || status == 3) {
+		tty_parse_client_features(c, "sync", ",");
+		tty_update_features(tty);
+	}
+	log_debug("%s: received DECRPM %.*s", c->name, (int)*size, buf);
+	tty->flags |= TTY_HAVESYNC;
+
+	return (0);
+}
+
 /*
  * Handle secondary device attributes input. Returns 0 for success, -1 for
  * failure, 1 for partial.