From 968382aa6a4b9c71fbc221aa4f0e899f6a83a260 Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicholas.marriott@gmail.com>
Date: Thu, 28 Nov 2019 12:35:18 +0000
Subject: [PATCH 01/29] Pass through SIXEL DCS sequences (treat similarly to
 the passthrough escape sequence) if it appears the terminal outside supports
 them.

---
 input.c        | 18 +++++++++++++-----
 screen-write.c | 15 +++++++++++++++
 tmux.1         |  2 ++
 tmux.h         |  7 ++++++-
 tty-keys.c     |  9 ++++++---
 tty-term.c     |  1 +
 tty.c          | 15 ++++++++++++++-
 7 files changed, 57 insertions(+), 10 deletions(-)

diff --git a/input.c b/input.c
index 452eac7f..b8d2f102 100644
--- a/input.c
+++ b/input.c
@@ -1305,8 +1305,8 @@ input_csi_dispatch(struct input_ctx *ictx)
 	if (ictx->flags & INPUT_DISCARD)
 		return (0);
 
-	log_debug("%s: '%c' \"%s\" \"%s\"",
-	    __func__, ictx->ch, ictx->interm_buf, ictx->param_buf);
+	log_debug("%s: '%c' \"%s\" \"%s\"", __func__, ictx->ch,
+	    ictx->interm_buf, ictx->param_buf);
 
 	if (input_split(ictx) != 0)
 		return (0);
@@ -2151,19 +2151,27 @@ static int
 input_dcs_dispatch(struct input_ctx *ictx)
 {
 	struct screen_write_ctx	*sctx = &ictx->ctx;
-	u_char			*buf = ictx->input_buf;
-	size_t			 len = ictx->input_len;
+	u_char			*buf = ictx->input_buf, *pbuf = ictx->param_buf;
+	size_t			 len = ictx->input_len, plen = ictx->param_len;
 	const char		 prefix[] = "tmux;";
 	const u_int		 prefixlen = (sizeof prefix) - 1;
 
 	if (ictx->flags & INPUT_DISCARD)
 		return (0);
 
-	log_debug("%s: \"%s\"", __func__, buf);
+	log_debug("%s: \"%s\" \"%s\" \"%s\"", __func__, buf, ictx->interm_buf,
+	    ictx->param_buf);
 
 	if (len >= prefixlen && strncmp(buf, prefix, prefixlen) == 0)
 		screen_write_rawstring(sctx, buf + prefixlen, len - prefixlen);
 
+	if (buf[0] == 'q') {
+		screen_write_rawsixel(sctx, (char *)"\033P", 2, 1);
+		screen_write_rawsixel(sctx, pbuf, plen, 1);
+		screen_write_rawsixel(sctx, buf, len, 1);
+		screen_write_rawsixel(sctx, (char *)"\033\\", 2, 0);
+	}
+
 	return (0);
 }
 
diff --git a/screen-write.c b/screen-write.c
index 43cb42b4..9bd28836 100644
--- a/screen-write.c
+++ b/screen-write.c
@@ -1671,3 +1671,18 @@ screen_write_rawstring(struct screen_write_ctx *ctx, u_char *str, u_int len)
 
 	tty_write(tty_cmd_rawstring, &ttyctx);
 }
+
+/* Write unmodified SIXEL data. */
+void
+screen_write_rawsixel(struct screen_write_ctx *ctx, u_char *str, u_int len,
+    int more)
+{
+	struct tty_ctx	ttyctx;
+
+	screen_write_initctx(ctx, &ttyctx);
+	ttyctx.ptr = str;
+	ttyctx.num = len;
+	ttyctx.more = more;
+
+	tty_write(tty_cmd_rawsixel, &ttyctx);
+}
diff --git a/tmux.1 b/tmux.1
index 9513bd79..aac4625c 100644
--- a/tmux.1
+++ b/tmux.1
@@ -5200,6 +5200,8 @@ $ printf '\e033[4 q'
 If
 .Em Se
 is not set, \&Ss with argument 0 will be used to reset the cursor style instead.
+.It Em \&Sxl
+Indicates that the terminal supports SIXEL.
 .It Em \&Tc
 Indicate that the terminal supports the
 .Ql direct colour
diff --git a/tmux.h b/tmux.h
index b7220b88..7c901b9d 100644
--- a/tmux.h
+++ b/tmux.h
@@ -446,6 +446,7 @@ enum tty_code_code {
 	TTYC_SMULX,
 	TTYC_SMUL,
 	TTYC_SMXX,
+	TTYC_SXL,
 	TTYC_SS,
 	TTYC_TC,
 	TTYC_TSL,
@@ -1145,6 +1146,7 @@ struct tty_term {
 
 #define TERM_256COLOURS 0x1
 #define TERM_EARLYWRAP 0x2
+#define TERM_SIXEL 0x4
 	int		 flags;
 
 	LIST_ENTRY(tty_term) entry;
@@ -1248,6 +1250,7 @@ struct tty_ctx {
 
 	u_int			 num;
 	void			*ptr;
+	int			 more;
 
 	/*
 	 * Cursor and region position before the screen was updated - this is
@@ -1947,7 +1950,7 @@ void	tty_draw_line(struct tty *, struct window_pane *, struct screen *,
 int	tty_open(struct tty *, char **);
 void	tty_close(struct tty *);
 void	tty_free(struct tty *);
-void	tty_set_type(struct tty *, int);
+void	tty_set_type(struct tty *, int, int);
 void	tty_write(void (*)(struct tty *, const struct tty_ctx *),
 	    struct tty_ctx *);
 void	tty_cmd_alignmenttest(struct tty *, const struct tty_ctx *);
@@ -1971,6 +1974,7 @@ void	tty_cmd_scrolldown(struct tty *, const struct tty_ctx *);
 void	tty_cmd_reverseindex(struct tty *, const struct tty_ctx *);
 void	tty_cmd_setselection(struct tty *, const struct tty_ctx *);
 void	tty_cmd_rawstring(struct tty *, const struct tty_ctx *);
+void	tty_cmd_rawsixel(struct tty *, const struct tty_ctx *);
 
 /* tty-term.c */
 extern struct tty_terms tty_terms;
@@ -2357,6 +2361,7 @@ void	 screen_write_collect_add(struct screen_write_ctx *,
 void	 screen_write_cell(struct screen_write_ctx *, const struct grid_cell *);
 void	 screen_write_setselection(struct screen_write_ctx *, u_char *, u_int);
 void	 screen_write_rawstring(struct screen_write_ctx *, u_char *, u_int);
+void	 screen_write_rawsixel(struct screen_write_ctx *, u_char *, u_int, int);
 
 /* screen-redraw.c */
 void	 screen_redraw_screen(struct client *);
diff --git a/tty-keys.c b/tty-keys.c
index 6be40d0e..e644addb 100644
--- a/tty-keys.c
+++ b/tty-keys.c
@@ -1005,7 +1005,7 @@ tty_keys_device_attributes(struct tty *tty, const char *buf, size_t len,
 	u_int			 i, n = 0;
 	char			 tmp[64], *endptr, p[32] = { 0 }, *cp, *next;
 	static const char	*types[] = TTY_TYPES;
-	int			 type;
+	int			 type, flags = 0;
 
 	*size = 0;
 
@@ -1068,9 +1068,12 @@ tty_keys_device_attributes(struct tty *tty, const char *buf, size_t len,
 		type = TTY_VT520;
 		break;
 	}
-	for (i = 2; i < n; i++)
+	for (i = 2; i < n; i++) {
 		log_debug("%s: DA feature: %d", c->name, p[i]);
-	tty_set_type(tty, type);
+		if (p[i] == 4)
+			flags |= TERM_SIXEL;
+	}
+	tty_set_type(tty, type, flags);
 
 	log_debug("%s: received DA %.*s (%s)", c->name, (int)*size, buf,
 	    types[type]);
diff --git a/tty-term.c b/tty-term.c
index 3ac9bc6c..ce3d690a 100644
--- a/tty-term.c
+++ b/tty-term.c
@@ -252,6 +252,7 @@ static const struct tty_term_code_entry tty_term_codes[] = {
 	[TTYC_SETRGBF] = { TTYCODE_STRING, "setrgbf" },
 	[TTYC_SETULC] = { TTYCODE_STRING, "Setulc" },
 	[TTYC_SE] = { TTYCODE_STRING, "Se" },
+	[TTYC_SXL] =  { TTYCODE_FLAG, "Sxl" },
 	[TTYC_SGR0] = { TTYCODE_STRING, "sgr0" },
 	[TTYC_SITM] = { TTYCODE_STRING, "sitm" },
 	[TTYC_SMACS] = { TTYCODE_STRING, "smacs" },
diff --git a/tty.c b/tty.c
index 594f02fa..cae2fd24 100644
--- a/tty.c
+++ b/tty.c
@@ -436,9 +436,10 @@ tty_free(struct tty *tty)
 }
 
 void
-tty_set_type(struct tty *tty, int type)
+tty_set_type(struct tty *tty, int type, int flags)
 {
 	tty->term_type = type;
+	tty->term_flags |= flags;
 
 	if (tty_use_margin(tty))
 		tty_puts(tty, "\033[?69h"); /* DECLRMM */
@@ -1865,6 +1866,18 @@ tty_cmd_rawstring(struct tty *tty, const struct tty_ctx *ctx)
 	tty_invalidate(tty);
 }
 
+void
+tty_cmd_rawsixel(struct tty *tty, const struct tty_ctx *ctx)
+{
+	int	flags = (tty->term->flags|tty->term_flags);
+
+	if ((flags & TERM_SIXEL) || tty_term_has(tty->term, TTYC_SXL)) {
+		tty_add(tty, ctx->ptr, ctx->num);
+		if (!ctx->more)
+			tty_invalidate(tty);
+	}
+}
+
 static void
 tty_cell(struct tty *tty, const struct grid_cell *gc, struct window_pane *wp)
 {

From a5b1e209417b7d3f5b0099642dd317c312f79377 Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicholas.marriott@gmail.com>
Date: Thu, 28 Nov 2019 14:20:22 +0000
Subject: [PATCH 02/29] Add a flag to disable blocking while sending a SIXEL
 image (turned off when the buffer hits 0 size).

---
 tmux.h | 1 +
 tty.c  | 6 ++++++
 2 files changed, 7 insertions(+)

diff --git a/tmux.h b/tmux.h
index 7c901b9d..b1e7f44e 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1203,6 +1203,7 @@ struct tty {
 #define TTY_OPENED 0x20
 #define TTY_FOCUS 0x40
 #define TTY_BLOCK 0x80
+#define TTY_NOBLOCK 0x100
 	int		 flags;
 
 	struct tty_term	*term;
diff --git a/tty.c b/tty.c
index cae2fd24..da21645f 100644
--- a/tty.c
+++ b/tty.c
@@ -211,6 +211,11 @@ tty_block_maybe(struct tty *tty)
 	size_t		 size = EVBUFFER_LENGTH(tty->out);
 	struct timeval	 tv = { .tv_usec = TTY_BLOCK_INTERVAL };
 
+	if (size == 0)
+		tty->flags &= ~TTY_NOBLOCK;
+	else if (tty->flags & TTY_NOBLOCK)
+		return (0);
+
 	if (size < TTY_BLOCK_START(tty))
 		return (0);
 
@@ -1872,6 +1877,7 @@ tty_cmd_rawsixel(struct tty *tty, const struct tty_ctx *ctx)
 	int	flags = (tty->term->flags|tty->term_flags);
 
 	if ((flags & TERM_SIXEL) || tty_term_has(tty->term, TTYC_SXL)) {
+		tty->flags |= TTY_NOBLOCK;
 		tty_add(tty, ctx->ptr, ctx->num);
 		if (!ctx->more)
 			tty_invalidate(tty);

From 0a15bbf3f1972dc84c5c84d5128024c1bc4c0074 Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicholas.marriott@gmail.com>
Date: Sat, 30 Nov 2019 09:15:35 +0000
Subject: [PATCH 03/29] Do not defer redraw if it is just the status line (will
 need to do more here I think).

---
 server-client.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/server-client.c b/server-client.c
index 2cfd8838..075b0ba1 100644
--- a/server-client.c
+++ b/server-client.c
@@ -1612,7 +1612,7 @@ server_client_check_redraw(struct client *c)
 	 * end up back here.
 	 */
 	needed = 0;
-	if (c->flags & CLIENT_ALLREDRAWFLAGS)
+	if (c->flags & (CLIENT_ALLREDRAWFLAGS & ~CLIENT_REDRAWSTATUS))
 		needed = 1;
 	else {
 		TAILQ_FOREACH(wp, &c->session->curw->window->panes, entry) {

From deb734c7f61c36e18ccc2e4fdab4f06a90575fc9 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Sun, 12 Jan 2020 20:20:20 +0000
Subject: [PATCH 04/29] Loop over all DA features, don't skip the first.

---
 tty-keys.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tty-keys.c b/tty-keys.c
index 6be40d0e..1d97b7d2 100644
--- a/tty-keys.c
+++ b/tty-keys.c
@@ -1038,7 +1038,7 @@ tty_keys_device_attributes(struct tty *tty, const char *buf, size_t len,
 	cp = tmp;
 	while ((next = strsep(&cp, ";")) != NULL) {
 		p[n] = strtoul(next, &endptr, 10);
-		if (*endptr != '\0' && *endptr != ';')
+		if (*endptr != '\0')
 			p[n] = 0;
 		n++;
 	}
@@ -1068,7 +1068,7 @@ tty_keys_device_attributes(struct tty *tty, const char *buf, size_t len,
 		type = TTY_VT520;
 		break;
 	}
-	for (i = 2; i < n; i++)
+	for (i = 1; i < n; i++)
 		log_debug("%s: DA feature: %d", c->name, p[i]);
 	tty_set_type(tty, type);
 

From 193e637de050e3757698812e9a87b869c87def6c Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Sun, 12 Jan 2020 21:07:07 +0000
Subject: [PATCH 05/29] The terminal type was never as much use as I expected
 so remove it in favour of a couple of flags for the features used (DECSLRM
 and DECFRA). Also rename the flag for no xenl to be more obvious while here.

---
 format.c   |  3 ---
 tmux.1     |  1 -
 tmux.h     | 25 ++++---------------------
 tty-keys.c | 40 +++++++++-------------------------------
 tty-term.c |  2 +-
 tty.c      | 23 +++++++++++------------
 6 files changed, 25 insertions(+), 69 deletions(-)

diff --git a/format.c b/format.c
index eaff6115..f5e7b2ce 100644
--- a/format.c
+++ b/format.c
@@ -2346,7 +2346,6 @@ format_defaults_client(struct format_tree *ft, struct client *c)
 	struct session	*s;
 	const char	*name;
 	struct tty	*tty = &c->tty;
-	const char	*types[] = TTY_TYPES;
 
 	if (ft->s == NULL)
 		ft->s = c->session;
@@ -2364,8 +2363,6 @@ format_defaults_client(struct format_tree *ft, struct client *c)
 
 	if (tty->term_name != NULL)
 		format_add(ft, "client_termname", "%s", tty->term_name);
-	if (tty->term_name != NULL)
-		format_add(ft, "client_termtype", "%s", types[tty->term_type]);
 
 	format_add_tv(ft, "client_created", &c->creation_time);
 	format_add_tv(ft, "client_activity", &c->activity_time);
diff --git a/tmux.1 b/tmux.1
index 1e8c13af..9c9cfb39 100644
--- a/tmux.1
+++ b/tmux.1
@@ -4227,7 +4227,6 @@ The following variables are available, where appropriate:
 .It Li "client_readonly" Ta "" Ta "1 if client is readonly"
 .It Li "client_session" Ta "" Ta "Name of the client's session"
 .It Li "client_termname" Ta "" Ta "Terminal name of client"
-.It Li "client_termtype" Ta "" Ta "Terminal type of client"
 .It Li "client_tty" Ta "" Ta "Pseudo terminal of client"
 .It Li "client_utf8" Ta "" Ta "1 if client supports UTF-8"
 .It Li "client_width" Ta "" Ta "Width of client"
diff --git a/tmux.h b/tmux.h
index 0a0fc1b5..7c7dcc99 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1168,7 +1168,9 @@ struct tty_term {
 	struct tty_code	*codes;
 
 #define TERM_256COLOURS 0x1
-#define TERM_EARLYWRAP 0x2
+#define TERM_NOXENL 0x2
+#define TERM_DECSLRM 0x4
+#define TERM_DECFRA 0x8
 	int		 flags;
 
 	LIST_ENTRY(tty_term) entry;
@@ -1230,16 +1232,6 @@ struct tty {
 	struct tty_term	*term;
 	char		*term_name;
 	int		 term_flags;
-	enum {
-		TTY_VT100,
-		TTY_VT101,
-		TTY_VT102,
-		TTY_VT220,
-		TTY_VT320,
-		TTY_VT420,
-		TTY_VT520,
-		TTY_UNKNOWN
-	} term_type;
 
 	u_int		 mouse_last_x;
 	u_int		 mouse_last_y;
@@ -1253,15 +1245,6 @@ struct tty {
 	struct event	 key_timer;
 	struct tty_key	*key_tree;
 };
-#define TTY_TYPES \
-	{ "VT100", \
-	  "VT101", \
-	  "VT102", \
-	  "VT220", \
-	  "VT320", \
-	  "VT420", \
-	  "VT520", \
-	  "Unknown" }
 
 /* TTY command context. */
 struct tty_ctx {
@@ -1992,7 +1975,7 @@ void	tty_draw_line(struct tty *, struct window_pane *, struct screen *,
 int	tty_open(struct tty *, char **);
 void	tty_close(struct tty *);
 void	tty_free(struct tty *);
-void	tty_set_type(struct tty *, int);
+void	tty_set_flags(struct tty *, int);
 void	tty_write(void (*)(struct tty *, const struct tty_ctx *),
 	    struct tty_ctx *);
 void	tty_cmd_alignmenttest(struct tty *, const struct tty_ctx *);
diff --git a/tty-keys.c b/tty-keys.c
index 1d97b7d2..4644340c 100644
--- a/tty-keys.c
+++ b/tty-keys.c
@@ -1001,11 +1001,10 @@ static int
 tty_keys_device_attributes(struct tty *tty, const char *buf, size_t len,
     size_t *size)
 {
-	struct client		*c = tty->client;
-	u_int			 i, n = 0;
-	char			 tmp[64], *endptr, p[32] = { 0 }, *cp, *next;
-	static const char	*types[] = TTY_TYPES;
-	int			 type;
+	struct client	*c = tty->client;
+	u_int		 i, n = 0;
+	char		 tmp[64], *endptr, p[32] = { 0 }, *cp, *next;
+	int		 flags = 0;
 
 	*size = 0;
 
@@ -1043,36 +1042,15 @@ tty_keys_device_attributes(struct tty *tty, const char *buf, size_t len,
 		n++;
 	}
 
-	/* Store terminal type. */
-	type = TTY_UNKNOWN;
+	/* Set terminal flags. */
 	switch (p[0]) {
-	case 1:
-		if (p[1] == 2)
-			type = TTY_VT100;
-		else if (p[1] == 0)
-			type = TTY_VT101;
-		break;
-	case 6:
-		type = TTY_VT102;
-		break;
-	case 62:
-		type = TTY_VT220;
-		break;
-	case 63:
-		type = TTY_VT320;
-		break;
-	case 64:
-		type = TTY_VT420;
-		break;
-	case 65:
-		type = TTY_VT520;
+	case 64: /* VT420 */
+		flags |= (TERM_DECFRA|TERM_DECSLRM);
 		break;
 	}
 	for (i = 1; i < n; i++)
 		log_debug("%s: DA feature: %d", c->name, p[i]);
-	tty_set_type(tty, type);
-
-	log_debug("%s: received DA %.*s (%s)", c->name, (int)*size, buf,
-	    types[type]);
+	log_debug("%s: received DA %.*s", c->name, (int)*size, buf);
+	tty_set_flags(tty, flags);
 	return (0);
 }
diff --git a/tty-term.c b/tty-term.c
index 52468faf..164ab2f1 100644
--- a/tty-term.c
+++ b/tty-term.c
@@ -538,7 +538,7 @@ tty_term_find(char *name, int fd, char **cause)
 	 * do the best possible.
 	 */
 	if (!tty_term_flag(term, TTYC_XENL))
-		term->flags |= TERM_EARLYWRAP;
+		term->flags |= TERM_NOXENL;
 
 	/* Generate ACS table. If none is present, use nearest ASCII. */
 	memset(term->acs, 0, sizeof term->acs);
diff --git a/tty.c b/tty.c
index 2d7acb17..c9843e90 100644
--- a/tty.c
+++ b/tty.c
@@ -74,7 +74,7 @@ static void	tty_default_attributes(struct tty *, struct window_pane *,
 		    u_int);
 
 #define tty_use_margin(tty) \
-	((tty)->term_type == TTY_VT420)
+	((tty->term->flags|tty->term_flags) & TERM_DECSLRM)
 
 #define tty_pane_full_width(tty, ctx) \
 	((ctx)->xoff == 0 && screen_size_x((ctx)->wp->screen) >= (tty)->sx)
@@ -115,9 +115,7 @@ tty_init(struct tty *tty, struct client *c, int fd, char *term)
 	tty->ccolour = xstrdup("");
 
 	tty->flags = 0;
-
 	tty->term_flags = 0;
-	tty->term_type = TTY_UNKNOWN;
 
 	return (0);
 }
@@ -438,9 +436,9 @@ tty_free(struct tty *tty)
 }
 
 void
-tty_set_type(struct tty *tty, int type)
+tty_set_flags(struct tty *tty, int flags)
 {
-	tty->term_type = type;
+	tty->term_flags |= flags;
 
 	if (tty_use_margin(tty))
 		tty_puts(tty, "\033[?69h"); /* DECLRMM */
@@ -543,7 +541,7 @@ tty_putc(struct tty *tty, u_char ch)
 {
 	const char	*acs;
 
-	if ((tty->term->flags & TERM_EARLYWRAP) &&
+	if ((tty->term->flags & TERM_NOXENL) &&
 	    ch >= 0x20 && ch != 0x7f &&
 	    tty->cy == tty->sy - 1 &&
 	    tty->cx + 1 >= tty->sx)
@@ -569,7 +567,7 @@ tty_putc(struct tty *tty, u_char ch)
 			 * where we think it should be after a line wrap - this
 			 * means it works on sensible terminals as well.
 			 */
-			if (tty->term->flags & TERM_EARLYWRAP)
+			if (tty->term->flags & TERM_NOXENL)
 				tty_putcode2(tty, TTYC_CUP, tty->cy, tty->cx);
 		} else
 			tty->cx++;
@@ -579,7 +577,7 @@ tty_putc(struct tty *tty, u_char ch)
 void
 tty_putn(struct tty *tty, const void *buf, size_t len, u_int width)
 {
-	if ((tty->term->flags & TERM_EARLYWRAP) &&
+	if ((tty->term->flags & TERM_NOXENL) &&
 	    tty->cy == tty->sy - 1 &&
 	    tty->cx + len >= tty->sx)
 		len = tty->sx - tty->cx - 1;
@@ -1129,7 +1127,8 @@ tty_clear_area(struct tty *tty, struct window_pane *wp, u_int py, u_int ny,
 		 * background colour isn't default (because it doesn't work
 		 * after SGR 0).
 		 */
-		if (tty->term_type == TTY_VT420 && !COLOUR_DEFAULT(bg)) {
+		if (((tty->term->flags|tty->term_flags) & TERM_DECFRA) &&
+		    !COLOUR_DEFAULT(bg)) {
 			xsnprintf(tmp, sizeof tmp, "\033[32;%u;%u;%u;%u$x",
 			    py + 1, px + 1, py + ny, px + nx);
 			tty_puts(tty, tmp);
@@ -1824,7 +1823,7 @@ tty_cmd_cells(struct tty *tty, const struct tty_ctx *ctx)
 	    ctx->xoff + ctx->ocx + ctx->num > ctx->ox + ctx->sx)) {
 		if (!ctx->wrapped ||
 		    !tty_pane_full_width(tty, ctx) ||
-		    (tty->term->flags & TERM_EARLYWRAP) ||
+		    (tty->term->flags & TERM_NOXENL) ||
 		    ctx->xoff + ctx->ocx != 0 ||
 		    ctx->yoff + ctx->ocy != tty->cy + 1 ||
 		    tty->cx < tty->sx ||
@@ -1873,7 +1872,7 @@ tty_cell(struct tty *tty, const struct grid_cell *gc, struct window_pane *wp)
 	const struct grid_cell	*gcp;
 
 	/* Skip last character if terminal is stupid. */
-	if ((tty->term->flags & TERM_EARLYWRAP) &&
+	if ((tty->term->flags & TERM_NOXENL) &&
 	    tty->cy == tty->sy - 1 &&
 	    tty->cx == tty->sx - 1)
 		return;
@@ -2032,7 +2031,7 @@ tty_cursor_pane_unless_wrap(struct tty *tty, const struct tty_ctx *ctx,
 {
 	if (!ctx->wrapped ||
 	    !tty_pane_full_width(tty, ctx) ||
-	    (tty->term->flags & TERM_EARLYWRAP) ||
+	    (tty->term->flags & TERM_NOXENL) ||
 	    ctx->xoff + cx != 0 ||
 	    ctx->yoff + cy != tty->cy + 1 ||
 	    tty->cx < tty->sx ||

From 381333c4a9fd521bee8a0287e648f0c6aeb96a0b Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Sun, 12 Jan 2020 22:00:20 +0000
Subject: [PATCH 06/29] Detect iTerm2 and enable DECSLRM.

---
 tty-keys.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 tty.c      |  2 +-
 2 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/tty-keys.c b/tty-keys.c
index 4644340c..5054c424 100644
--- a/tty-keys.c
+++ b/tty-keys.c
@@ -52,6 +52,8 @@ static int	tty_keys_clipboard(struct tty *, const char *, size_t,
 		    size_t *);
 static int	tty_keys_device_attributes(struct tty *, const char *, size_t,
 		    size_t *);
+static int	tty_keys_device_status_report(struct tty *, const char *,
+		    size_t, size_t *);
 
 /* Default raw keys. */
 struct tty_default_key_raw {
@@ -607,6 +609,17 @@ tty_keys_next(struct tty *tty)
 		goto partial_key;
 	}
 
+	/* Is this a device status report response? */
+	switch (tty_keys_device_status_report(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 mouse key press? */
 	switch (tty_keys_mouse(tty, buf, len, &size, &m)) {
 	case 0:		/* yes */
@@ -1054,3 +1067,47 @@ tty_keys_device_attributes(struct tty *tty, const char *buf, size_t len,
 	tty_set_flags(tty, flags);
 	return (0);
 }
+
+/*
+ * Handle device status report input. Returns 0 for success, -1 for failure, 1
+ * for partial.
+ */
+static int
+tty_keys_device_status_report(struct tty *tty, const char *buf, size_t len,
+    size_t *size)
+{
+	struct client	*c = tty->client;
+	u_int		 i;
+	char		 tmp[64];
+	int		 flags = 0;
+
+	*size = 0;
+
+	/* First three bytes are always \033[. */
+	if (buf[0] != '\033')
+		return (-1);
+	if (len == 1)
+		return (1);
+	if (buf[1] != '[')
+		return (-1);
+	if (len == 2)
+		return (1);
+
+	/* Copy the rest up to a 'n'. */
+	for (i = 0; i < (sizeof tmp) - 1 && buf[2 + i] != 'n'; i++) {
+		if (2 + i == len)
+			return (1);
+		tmp[i] = buf[2 + i];
+	}
+	if (i == (sizeof tmp) - 1)
+		return (-1);
+	tmp[i] = '\0';
+	*size = 3 + i;
+
+	/* Set terminal flags. */
+	if (strncmp(tmp, "ITERM2 ", 7) == 0)
+		flags |= TERM_DECSLRM;
+	log_debug("%s: received DSR %.*s", c->name, (int)*size, buf);
+	tty_set_flags(tty, flags);
+	return (0);
+}
diff --git a/tty.c b/tty.c
index c9843e90..2d4b4cc0 100644
--- a/tty.c
+++ b/tty.c
@@ -327,7 +327,7 @@ tty_start_tty(struct tty *tty)
 			tty->flags |= TTY_FOCUS;
 			tty_puts(tty, "\033[?1004h");
 		}
-		tty_puts(tty, "\033[c");
+		tty_puts(tty, "\033[c\033[1337n");
 	}
 
 	tty->flags |= TTY_STARTED;

From 04eee2410df4a85005c9562db13a1fec93d7c2e4 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Mon, 13 Jan 2020 07:51:54 +0000
Subject: [PATCH 07/29] Treat plausible but invalid keys (like C-BSpace) as
 literal like any other unrecognised string passed to send-keys. Reported by
 Anthony Sottile in GitHub issue 2049.

---
 cmd-send-keys.c | 14 +++++++++++---
 input-keys.c    | 17 +++++++++--------
 tmux.h          |  4 ++--
 window.c        | 14 ++++++++------
 4 files changed, 30 insertions(+), 19 deletions(-)

diff --git a/cmd-send-keys.c b/cmd-send-keys.c
index ddbab6f7..cc04a73f 100644
--- a/cmd-send-keys.c
+++ b/cmd-send-keys.c
@@ -60,6 +60,9 @@ static struct cmdq_item *
 cmd_send_keys_inject_key(struct client *c, struct cmd_find_state *fs,
     struct cmdq_item *item, key_code key)
 {
+	struct session			*s = fs->s;
+	struct winlink			*wl = fs->wl;
+	struct window_pane		*wp = fs->wp;
 	struct window_mode_entry	*wme;
 	struct key_table		*table;
 	struct key_binding		*bd;
@@ -68,7 +71,8 @@ cmd_send_keys_inject_key(struct client *c, struct cmd_find_state *fs,
 	if (wme == NULL || wme->mode->key_table == NULL) {
 		if (options_get_number(fs->wp->window->options, "xterm-keys"))
 			key |= KEYC_XTERM;
-		window_pane_key(fs->wp, item->client, fs->s, fs->wl, key, NULL);
+		if (window_pane_key(wp, item->client, s, wl, key, NULL) != 0)
+			return (NULL);
 		return (item);
 	}
 	table = key_bindings_get_table(wme->mode->key_table(wme), 1);
@@ -87,6 +91,7 @@ cmd_send_keys_inject_string(struct client *c, struct cmd_find_state *fs,
     struct cmdq_item *item, struct args *args, int i)
 {
 	const char		*s = args->argv[i];
+	struct cmdq_item	*new_item;
 	struct utf8_data	*ud, *uc;
 	wchar_t			 wc;
 	key_code		 key;
@@ -104,8 +109,11 @@ cmd_send_keys_inject_string(struct client *c, struct cmd_find_state *fs,
 	literal = args_has(args, 'l');
 	if (!literal) {
 		key = key_string_lookup_string(s);
-		if (key != KEYC_NONE && key != KEYC_UNKNOWN)
-			return (cmd_send_keys_inject_key(c, fs, item, key));
+		if (key != KEYC_NONE && key != KEYC_UNKNOWN) {
+			new_item = cmd_send_keys_inject_key(c, fs, item, key);
+			if (new_item != NULL)
+				return (new_item);
+		}
 		literal = 1;
 	}
 	if (literal) {
diff --git a/input-keys.c b/input-keys.c
index 01f9ad9d..5c7e8b1f 100644
--- a/input-keys.c
+++ b/input-keys.c
@@ -150,7 +150,7 @@ input_split2(u_int c, u_char *dst)
 }
 
 /* Translate a key code into an output key sequence. */
-void
+int
 input_key(struct window_pane *wp, key_code key, struct mouse_event *m)
 {
 	const struct input_key_ent	*ike;
@@ -167,14 +167,14 @@ input_key(struct window_pane *wp, key_code key, struct mouse_event *m)
 	if (KEYC_IS_MOUSE(key)) {
 		if (m != NULL && m->wp != -1 && (u_int)m->wp == wp->id)
 			input_key_mouse(wp, m);
-		return;
+		return (0);
 	}
 
 	/* Literal keys go as themselves (can't be more than eight bits). */
 	if (key & KEYC_LITERAL) {
 		ud.data[0] = (u_char)key;
 		bufferevent_write(wp->event, &ud.data[0], 1);
-		return;
+		return (0);
 	}
 
 	/* Is this backspace? */
@@ -195,15 +195,15 @@ input_key(struct window_pane *wp, key_code key, struct mouse_event *m)
 			bufferevent_write(wp->event, "\033", 1);
 		ud.data[0] = justkey;
 		bufferevent_write(wp->event, &ud.data[0], 1);
-		return;
+		return (0);
 	}
 	if (justkey > 0x7f && justkey < KEYC_BASE) {
 		if (utf8_split(justkey, &ud) != UTF8_DONE)
-			return;
+			return (-1);
 		if (key & KEYC_ESCAPE)
 			bufferevent_write(wp->event, "\033", 1);
 		bufferevent_write(wp->event, ud.data, ud.size);
-		return;
+		return (0);
 	}
 
 	/*
@@ -214,7 +214,7 @@ input_key(struct window_pane *wp, key_code key, struct mouse_event *m)
 		if ((out = xterm_keys_lookup(key)) != NULL) {
 			bufferevent_write(wp->event, out, strlen(out));
 			free(out);
-			return;
+			return (0);
 		}
 	}
 	key &= ~KEYC_XTERM;
@@ -237,7 +237,7 @@ input_key(struct window_pane *wp, key_code key, struct mouse_event *m)
 	}
 	if (i == nitems(input_keys)) {
 		log_debug("key 0x%llx missing", key);
-		return;
+		return (-1);
 	}
 	dlen = strlen(ike->data);
 	log_debug("found key 0x%llx: \"%s\"", key, ike->data);
@@ -246,6 +246,7 @@ input_key(struct window_pane *wp, key_code key, struct mouse_event *m)
 	if (key & KEYC_ESCAPE)
 		bufferevent_write(wp->event, "\033", 1);
 	bufferevent_write(wp->event, ike->data, dlen);
+	return (0);
 }
 
 /* Translate mouse and output. */
diff --git a/tmux.h b/tmux.h
index 7c7dcc99..75e483c5 100644
--- a/tmux.h
+++ b/tmux.h
@@ -2275,7 +2275,7 @@ void	 input_parse(struct window_pane *);
 void	 input_parse_buffer(struct window_pane *, u_char *, size_t);
 
 /* input-key.c */
-void	 input_key(struct window_pane *, key_code, struct mouse_event *);
+int	 input_key(struct window_pane *, key_code, struct mouse_event *);
 
 /* xterm-keys.c */
 char	*xterm_keys_lookup(key_code);
@@ -2498,7 +2498,7 @@ int		 window_pane_set_mode(struct window_pane *,
 		     struct args *);
 void		 window_pane_reset_mode(struct window_pane *);
 void		 window_pane_reset_mode_all(struct window_pane *);
-void		 window_pane_key(struct window_pane *, struct client *,
+int		 window_pane_key(struct window_pane *, struct client *,
 		     struct session *, struct winlink *, key_code,
 		     struct mouse_event *);
 int		 window_pane_visible(struct window_pane *);
diff --git a/window.c b/window.c
index 64c95855..bd25b5d1 100644
--- a/window.c
+++ b/window.c
@@ -1229,7 +1229,7 @@ window_pane_reset_mode_all(struct window_pane *wp)
 		window_pane_reset_mode(wp);
 }
 
-void
+int
 window_pane_key(struct window_pane *wp, struct client *c, struct session *s,
     struct winlink *wl, key_code key, struct mouse_event *m)
 {
@@ -1237,23 +1237,24 @@ window_pane_key(struct window_pane *wp, struct client *c, struct session *s,
 	struct window_pane		*wp2;
 
 	if (KEYC_IS_MOUSE(key) && m == NULL)
-		return;
+		return (-1);
 
 	wme = TAILQ_FIRST(&wp->modes);
 	if (wme != NULL) {
 		wp->modelast = time(NULL);
 		if (wme->mode->key != NULL)
 			wme->mode->key(wme, c, s, wl, (key & ~KEYC_XTERM), m);
-		return;
+		return (0);
 	}
 
 	if (wp->fd == -1 || wp->flags & PANE_INPUTOFF)
-		return;
+		return (0);
 
-	input_key(wp, key, m);
+	if (input_key(wp, key, m) != 0)
+		return (-1);
 
 	if (KEYC_IS_MOUSE(key))
-		return;
+		return (0);
 	if (options_get_number(wp->window->options, "synchronize-panes")) {
 		TAILQ_FOREACH(wp2, &wp->window->panes, entry) {
 			if (wp2 != wp &&
@@ -1264,6 +1265,7 @@ window_pane_key(struct window_pane *wp, struct client *c, struct session *s,
 				input_key(wp2, key, NULL);
 		}
 	}
+	return (0);
 }
 
 int

From 835a6c0cf088437e318783c96b142c7dc26c290f Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Mon, 13 Jan 2020 08:12:53 +0000
Subject: [PATCH 08/29] Be more specific in the DSR we are looking for so it
 doesn't get confused with mouse sequences. Also set a flag and don't bother
 checking for it if we have already seen it (same for DA), and don't check if
 we never asked for it.

---
 tmux.h     |  2 ++
 tty-keys.c | 14 ++++++++++++++
 tty.c      |  5 +++--
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/tmux.h b/tmux.h
index 75e483c5..adc1a240 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1227,6 +1227,8 @@ struct tty {
 #define TTY_OPENED 0x20
 #define TTY_FOCUS 0x40
 #define TTY_BLOCK 0x80
+#define TTY_HAVEDA 0x100
+#define TTY_HAVEDSR 0x200
 	int		 flags;
 
 	struct tty_term	*term;
diff --git a/tty-keys.c b/tty-keys.c
index 5054c424..968f67ca 100644
--- a/tty-keys.c
+++ b/tty-keys.c
@@ -1020,6 +1020,8 @@ tty_keys_device_attributes(struct tty *tty, const char *buf, size_t len,
 	int		 flags = 0;
 
 	*size = 0;
+	if (tty->flags & TTY_HAVEDA)
+		return (-1);
 
 	/* First three bytes are always \033[?. */
 	if (buf[0] != '\033')
@@ -1064,7 +1066,10 @@ tty_keys_device_attributes(struct tty *tty, const char *buf, size_t len,
 	for (i = 1; i < n; i++)
 		log_debug("%s: DA feature: %d", c->name, p[i]);
 	log_debug("%s: received DA %.*s", c->name, (int)*size, buf);
+
 	tty_set_flags(tty, flags);
+	tty->flags |= TTY_HAVEDA;
+
 	return (0);
 }
 
@@ -1082,6 +1087,8 @@ tty_keys_device_status_report(struct tty *tty, const char *buf, size_t len,
 	int		 flags = 0;
 
 	*size = 0;
+	if (tty->flags & TTY_HAVEDSR)
+		return (-1);
 
 	/* First three bytes are always \033[. */
 	if (buf[0] != '\033')
@@ -1092,6 +1099,10 @@ tty_keys_device_status_report(struct tty *tty, const char *buf, size_t len,
 		return (-1);
 	if (len == 2)
 		return (1);
+	if (buf[2] != 'I')
+		return (-1);
+	if (len == 3)
+		return (1);
 
 	/* Copy the rest up to a 'n'. */
 	for (i = 0; i < (sizeof tmp) - 1 && buf[2 + i] != 'n'; i++) {
@@ -1108,6 +1119,9 @@ tty_keys_device_status_report(struct tty *tty, const char *buf, size_t len,
 	if (strncmp(tmp, "ITERM2 ", 7) == 0)
 		flags |= TERM_DECSLRM;
 	log_debug("%s: received DSR %.*s", c->name, (int)*size, buf);
+
 	tty_set_flags(tty, flags);
+	tty->flags |= TTY_HAVEDSR;
+
 	return (0);
 }
diff --git a/tty.c b/tty.c
index 2d4b4cc0..a1324528 100644
--- a/tty.c
+++ b/tty.c
@@ -327,8 +327,9 @@ tty_start_tty(struct tty *tty)
 			tty->flags |= TTY_FOCUS;
 			tty_puts(tty, "\033[?1004h");
 		}
-		tty_puts(tty, "\033[c\033[1337n");
-	}
+		tty_puts(tty, "\033[c\033[1337n"); /* DA and DSR */
+	} else
+		tty->flags |= (TTY_HAVEDA|TTY_HAVEDSR);
 
 	tty->flags |= TTY_STARTED;
 	tty_invalidate(tty);

From da515570dc13daefc92e26a5c5417e1f190f80e8 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Mon, 13 Jan 2020 11:59:21 +0000
Subject: [PATCH 09/29] Stop handling DA and DSR after a second (they should be
 the first thing sent) so this should be plenty.

---
 tmux.h |  1 +
 tty.c  | 17 +++++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/tmux.h b/tmux.h
index adc1a240..ac555be5 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1179,6 +1179,7 @@ LIST_HEAD(tty_terms, tty_term);
 
 struct tty {
 	struct client	*client;
+	struct event	 start_timer;
 
 	u_int		 sx;
 	u_int		 sy;
diff --git a/tty.c b/tty.c
index a1324528..3d58f05b 100644
--- a/tty.c
+++ b/tty.c
@@ -285,11 +285,22 @@ tty_open(struct tty *tty, char **cause)
 	return (0);
 }
 
+static void
+tty_start_timer_callback(__unused int fd, __unused short events, void *data)
+{
+	struct tty	*tty = data;
+	struct client	*c = tty->client;
+
+	log_debug("%s: start timer fired", c->name);
+	tty->flags |= (TTY_HAVEDA|TTY_HAVEDSR);
+}
+
 void
 tty_start_tty(struct tty *tty)
 {
 	struct client	*c = tty->client;
 	struct termios	 tio;
+	struct timeval	 tv = { .tv_sec = 1 };
 
 	if (tty->fd != -1 && tcgetattr(tty->fd, &tty->tio) == 0) {
 		setblocking(tty->fd, 0);
@@ -328,9 +339,13 @@ tty_start_tty(struct tty *tty)
 			tty_puts(tty, "\033[?1004h");
 		}
 		tty_puts(tty, "\033[c\033[1337n"); /* DA and DSR */
+
 	} else
 		tty->flags |= (TTY_HAVEDA|TTY_HAVEDSR);
 
+	evtimer_set(&tty->start_timer, tty_start_timer_callback, tty);
+	evtimer_add(&tty->start_timer, &tv);
+
 	tty->flags |= TTY_STARTED;
 	tty_invalidate(tty);
 
@@ -351,6 +366,8 @@ tty_stop_tty(struct tty *tty)
 		return;
 	tty->flags &= ~TTY_STARTED;
 
+	evtimer_del(&tty->start_timer);
+
 	event_del(&tty->timer);
 	tty->flags &= ~TTY_BLOCK;
 

From cdf138372c4b7a0cc48e15c1ad6412a88db08fb8 Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicholas.marriott@gmail.com>
Date: Tue, 14 Jan 2020 16:02:22 +0000
Subject: [PATCH 10/29] Add to CHANGES.

---
 CHANGES | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/CHANGES b/CHANGES
index cd3a1b8a..ae980bb0 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,5 +1,22 @@
 CHANGES FROM 3.0 to X.X
 
+* Treat plausible but invalid keys (like C-BSpace) as literal like any other
+  unrecognised string passed to send-keys
+
+* Detect iTerm2 and enable use of DECSLRM (much faster with horizontally split
+  windows).
+
+* Add -Z to default switch-client command in tree mode.
+
+* Add ~ to quoted characters for %%%.
+
+* Document client exit messages in the manual page.
+
+* Do not let read-only clients limit the size.
+
+* Add a number of new formats to inspect what sessions and clients a window is
+  present or active in.
+
 * Change file reading and writing to go through the client if necessary. This
   fixes commands like "tmux loadb /dev/fd/X". Also modify source-file to
   support "-" for standard input, like load-buffer and save-buffer.

From 9169ee0e874a9e4c46eda77abca075b9ec38dbb6 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Sat, 25 Jan 2020 16:40:32 +0000
Subject: [PATCH 11/29] Mention swap-window -d, GitHub issue 2068.

---
 tmux.1 | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tmux.1 b/tmux.1
index 9c9cfb39..eb5087be 100644
--- a/tmux.1
+++ b/tmux.1
@@ -2533,10 +2533,11 @@ This is similar to
 except the source and destination windows are swapped.
 It is an error if no window exists at
 .Ar src-window .
+If
+.Fl d
+is given, the new window does not become the current window.
 .Pp
-Like
-.Ic swap-pane ,
-if
+If
 .Fl s
 is omitted and a marked pane is present (see
 .Ic select-pane

From 74b424075c6d0ee668343936624b12cea10f3f19 Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicholas.marriott@gmail.com>
Date: Sat, 25 Jan 2020 16:41:49 +0000
Subject: [PATCH 12/29] Use FNM_IGNORECASE if present, from Eric N Vander Weele
 in GitHub issue 2067.

---
 compat.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/compat.h b/compat.h
index 794ac67d..70801d0d 100644
--- a/compat.h
+++ b/compat.h
@@ -171,8 +171,12 @@ void	warnx(const char *, ...);
 #endif
 
 #ifndef FNM_CASEFOLD
+#ifdef FNM_IGNORECASE
+#define FNM_CASEFOLD FNM_IGNORECASE
+#else
 #define FNM_CASEFOLD 0
 #endif
+#endif
 
 #ifndef INFTIM
 #define INFTIM -1

From 2e39b621c9b29b58b4bfe761989b14f0f13d07b6 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Mon, 27 Jan 2020 08:23:42 +0000
Subject: [PATCH 13/29] Change so that assignments may be specified alone - a
 command isn't required. GitHub issue 2062.

---
 cmd-parse.y | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/cmd-parse.y b/cmd-parse.y
index 97b50f57..41bcdaa8 100644
--- a/cmd-parse.y
+++ b/cmd-parse.y
@@ -133,7 +133,12 @@ statements	: statement '\n'
 			free($2);
 		}
 
-statement	: condition
+statement	: /* empty */
+		{
+			$$ = xmalloc (sizeof *$$);
+			TAILQ_INIT($$);
+		}
+		| condition
 		{
 			struct cmd_parse_state	*ps = &parse_state;
 
@@ -144,11 +149,6 @@ statement	: condition
 				cmd_parse_free_commands($1);
 			}
 		}
-		| assignment
-		{
-			$$ = xmalloc (sizeof *$$);
-			TAILQ_INIT($$);
-		}
 		| commands
 		{
 			struct cmd_parse_state	*ps = &parse_state;
@@ -194,8 +194,10 @@ expanded	: format
 			free($1);
 		}
 
-assignment	: /* empty */
-		| EQUALS
+optional_assignment	: /* empty */
+			| assignment
+
+assignment	: EQUALS
 		{
 			struct cmd_parse_state	*ps = &parse_state;
 			int			 flags = ps->input->flags;
@@ -372,7 +374,15 @@ commands	: command
 			$$ = $1;
 		}
 
-command		: assignment TOKEN
+command		: assignment
+		{
+			struct cmd_parse_state	*ps = &parse_state;
+
+			$$ = xcalloc(1, sizeof *$$);
+			$$->name = NULL;
+			$$->line = ps->input->line;
+		}
+		| optional_assignment TOKEN
 		{
 			struct cmd_parse_state	*ps = &parse_state;
 
@@ -381,7 +391,7 @@ command		: assignment TOKEN
 			$$->line = ps->input->line;
 
 		}
-		| assignment TOKEN arguments
+		| optional_assignment TOKEN arguments
 		{
 			struct cmd_parse_state	*ps = &parse_state;
 
@@ -631,6 +641,8 @@ cmd_parse_build_commands(struct cmd_parse_commands *cmds,
 	 * command list.
 	 */
 	TAILQ_FOREACH_SAFE(cmd, cmds, entry, next) {
+		if (cmd->name == NULL)
+			continue;
 		alias = cmd_get_alias(cmd->name);
 		if (alias == NULL)
 			continue;
@@ -676,6 +688,8 @@ cmd_parse_build_commands(struct cmd_parse_commands *cmds,
 	 */
 	result = cmd_list_new();
 	TAILQ_FOREACH(cmd, cmds, entry) {
+		if (cmd->name == NULL)
+			continue;
 		log_debug("%s: %u %s", __func__, cmd->line, cmd->name);
 		cmd_log_argv(cmd->argc, cmd->argv, __func__);
 

From d0b8d036be97efc885f879aa63ce9bbb0efd8222 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Mon, 27 Jan 2020 08:53:13 +0000
Subject: [PATCH 14/29] Add support for adding a note to a key binding (with
 bind-key -N) and use this to add descriptions to the default key bindings. A
 new -N flag to list-keys shows key bindings with notes rather than the
 default bind-key command used to create them. Change the default ? binding to
 use this to show a readable summary of keys.

Also extend command-prompt to return the name of the key pressed and add
a default binding (/) to show the note for the next key pressed

Suggested by Alex Tremblay in GitHub issue 2000.
---
 cmd-bind-key.c       |  12 ++--
 cmd-command-prompt.c |   6 +-
 cmd-list-keys.c      | 150 ++++++++++++++++++++++++++++++++++++--
 key-bindings.c       | 168 ++++++++++++++++++++++---------------------
 status.c             |   8 ++-
 tmux.1               |  48 ++++++++++---
 tmux.h               |   5 +-
 7 files changed, 292 insertions(+), 105 deletions(-)

diff --git a/cmd-bind-key.c b/cmd-bind-key.c
index 2af15d29..27f75dd0 100644
--- a/cmd-bind-key.c
+++ b/cmd-bind-key.c
@@ -33,8 +33,8 @@ const struct cmd_entry cmd_bind_key_entry = {
 	.name = "bind-key",
 	.alias = "bind",
 
-	.args = { "cnrT:", 2, -1 },
-	.usage = "[-cnr] [-T key-table] key "
+	.args = { "cnrN:T:", 2, -1 },
+	.usage = "[-cnr] [-T key-table] [-N note] key "
 	         "command [arguments]",
 
 	.flags = CMD_AFTERHOOK,
@@ -46,10 +46,10 @@ cmd_bind_key_exec(struct cmd *self, struct cmdq_item *item)
 {
 	struct args		 *args = self->args;
 	key_code		  key;
-	const char		 *tablename;
+	const char		 *tablename, *note;
 	struct cmd_parse_result	 *pr;
 	char			**argv = args->argv;
-	int			  argc = args->argc;
+	int			  argc = args->argc, repeat;
 
 	key = key_string_lookup_string(argv[0]);
 	if (key == KEYC_NONE || key == KEYC_UNKNOWN) {
@@ -63,6 +63,7 @@ cmd_bind_key_exec(struct cmd *self, struct cmdq_item *item)
 		tablename = "root";
 	else
 		tablename = "prefix";
+	repeat = args_has(args, 'r');
 
 	if (argc == 2)
 		pr = cmd_parse_from_string(argv[1], NULL);
@@ -79,6 +80,7 @@ cmd_bind_key_exec(struct cmd *self, struct cmdq_item *item)
 	case CMD_PARSE_SUCCESS:
 		break;
 	}
-	key_bindings_add(tablename, key, args_has(args, 'r'), pr->cmdlist);
+	note = args_get(args, 'N');
+	key_bindings_add(tablename, key, note, repeat, pr->cmdlist);
 	return (CMD_RETURN_NORMAL);
 }
diff --git a/cmd-command-prompt.c b/cmd-command-prompt.c
index 603ddb0a..9f0ea19f 100644
--- a/cmd-command-prompt.c
+++ b/cmd-command-prompt.c
@@ -40,8 +40,8 @@ const struct cmd_entry cmd_command_prompt_entry = {
 	.name = "command-prompt",
 	.alias = NULL,
 
-	.args = { "1iI:Np:t:", 0, 1 },
-	.usage = "[-1Ni] [-I inputs] [-p prompts] " CMD_TARGET_CLIENT_USAGE " "
+	.args = { "1kiI:Np:t:", 0, 1 },
+	.usage = "[-1kiN] [-I inputs] [-p prompts] " CMD_TARGET_CLIENT_USAGE " "
 		 "[template]",
 
 	.flags = 0,
@@ -122,6 +122,8 @@ cmd_command_prompt_exec(struct cmd *self, struct cmdq_item *item)
 		cdata->flags |= PROMPT_NUMERIC;
 	else if (args_has(args, 'i'))
 		cdata->flags |= PROMPT_INCREMENTAL;
+	else if (args_has(args, 'k'))
+		cdata->flags |= PROMPT_KEY;
 	status_prompt_set(c, prompt, input, cmd_command_prompt_callback,
 	    cmd_command_prompt_free, cdata, cdata->flags);
 	free(prompt);
diff --git a/cmd-list-keys.c b/cmd-list-keys.c
index 8636b70a..e9e75a72 100644
--- a/cmd-list-keys.c
+++ b/cmd-list-keys.c
@@ -36,8 +36,8 @@ const struct cmd_entry cmd_list_keys_entry = {
 	.name = "list-keys",
 	.alias = "lsk",
 
-	.args = { "T:", 0, 0 },
-	.usage = "[-T key-table]",
+	.args = { "1NP:T:", 0, 1 },
+	.usage = "[-1N] [-P prefix-string] [-T key-table] [key]",
 
 	.flags = CMD_STARTSERVER|CMD_AFTERHOOK,
 	.exec = cmd_list_keys_exec
@@ -54,6 +54,88 @@ const struct cmd_entry cmd_list_commands_entry = {
 	.exec = cmd_list_keys_exec
 };
 
+static u_int
+cmd_list_keys_get_width(const char *tablename, key_code only)
+{
+	struct key_table	*table;
+	struct key_binding	*bd;
+	u_int			 width, keywidth = 0;
+
+	table = key_bindings_get_table(tablename, 0);
+	if (table == NULL)
+		return (0);
+	bd = key_bindings_first(table);
+	while (bd != NULL) {
+		if ((only != KEYC_UNKNOWN && bd->key != only) ||
+		    KEYC_IS_MOUSE(bd->key) ||
+		    bd->note == NULL) {
+			bd = key_bindings_next(table, bd);
+			continue;
+		}
+		width = utf8_cstrwidth(key_string_lookup_key(bd->key));
+		if (width > keywidth)
+			keywidth = width;
+
+		bd = key_bindings_next(table, bd);
+	}
+	return (keywidth);
+}
+
+static int
+cmd_list_keys_print_notes(struct cmdq_item *item, struct args *args,
+    const char *tablename, u_int keywidth, key_code only, const char *prefix)
+{
+	struct client		*c = cmd_find_client(item, NULL, 1);
+	struct key_table	*table;
+	struct key_binding	*bd;
+	const char		*key;
+	char			*tmp;
+	int	                 found = 0;
+
+	table = key_bindings_get_table(tablename, 0);
+	if (table == NULL)
+		return (0);
+	bd = key_bindings_first(table);
+	while (bd != NULL) {
+		if ((only != KEYC_UNKNOWN && bd->key != only) ||
+		    KEYC_IS_MOUSE(bd->key) ||
+		    bd->note == NULL) {
+			bd = key_bindings_next(table, bd);
+			continue;
+		}
+		found = 1;
+		key = key_string_lookup_key(bd->key);
+
+		tmp = utf8_padcstr(key, keywidth + 1);
+		if (args_has(args, '1') && c != NULL)
+			status_message_set(c, "%s%s%s", prefix, tmp, bd->note);
+		else
+			cmdq_print(item, "%s%s%s", prefix, tmp, bd->note);
+		free(tmp);
+
+		if (args_has(args, '1'))
+			break;
+		bd = key_bindings_next(table, bd);
+	}
+	return (found);
+}
+
+static char *
+cmd_list_keys_get_prefix(struct args *args, key_code *prefix)
+{
+	char	*s;
+
+	*prefix = options_get_number(global_s_options, "prefix");
+	if (!args_has(args, 'P')) {
+		if (*prefix != KEYC_NONE)
+			xasprintf(&s, "%s ", key_string_lookup_key(*prefix));
+		else
+			s = xstrdup("");
+	} else
+		s = xstrdup(args_get(args, 'P'));
+	return (s);
+}
+
 static enum cmd_retval
 cmd_list_keys_exec(struct cmd *self, struct cmdq_item *item)
 {
@@ -61,19 +143,63 @@ cmd_list_keys_exec(struct cmd *self, struct cmdq_item *item)
 	struct key_table	*table;
 	struct key_binding	*bd;
 	const char		*tablename, *r;
-	char			*key, *cp, *tmp;
-	int			 repeat, width, tablewidth, keywidth;
+	char			*key, *cp, *tmp, *start, *empty;
+	key_code		 prefix, only = KEYC_UNKNOWN;
+	int			 repeat, width, tablewidth, keywidth, found = 0;
 	size_t			 tmpsize, tmpused, cplen;
 
 	if (self->entry == &cmd_list_commands_entry)
 		return (cmd_list_keys_commands(self, item));
 
+	if (args->argc != 0) {
+		only = key_string_lookup_string(args->argv[0]);
+		if (only == KEYC_UNKNOWN) {
+			cmdq_error(item, "invalid key: %s", args->argv[0]);
+			return (CMD_RETURN_ERROR);
+		}
+	}
+
 	tablename = args_get(args, 'T');
 	if (tablename != NULL && key_bindings_get_table(tablename, 0) == NULL) {
 		cmdq_error(item, "table %s doesn't exist", tablename);
 		return (CMD_RETURN_ERROR);
 	}
 
+	if (args_has(args, 'N')) {
+		if (tablename == NULL) {
+			start = cmd_list_keys_get_prefix(args, &prefix);
+			keywidth = cmd_list_keys_get_width("root", only);
+			if (prefix != KEYC_NONE) {
+				width = cmd_list_keys_get_width("prefix", only);
+				if (width == 0)
+					prefix = KEYC_NONE;
+				else if (width > keywidth)
+					keywidth = width;
+			}
+			empty = utf8_padcstr("", utf8_cstrwidth(start));
+
+			found = cmd_list_keys_print_notes(item, args, "root",
+			    keywidth, only, empty);
+			if (prefix != KEYC_NONE) {
+				if (cmd_list_keys_print_notes(item, args,
+				    "prefix", keywidth, only, start))
+					found = 1;
+			}
+			free(empty);
+		} else {
+			if (args_has(args, 'P'))
+				start = xstrdup(args_get(args, 'P'));
+			else
+				start = xstrdup("");
+			keywidth = cmd_list_keys_get_width(tablename, only);
+			found = cmd_list_keys_print_notes(item, args, tablename,
+			    keywidth, only, start);
+
+		}
+		free(start);
+		goto out;
+	}
+
 	repeat = 0;
 	tablewidth = keywidth = 0;
 	table = key_bindings_first_table ();
@@ -84,6 +210,10 @@ cmd_list_keys_exec(struct cmd *self, struct cmdq_item *item)
 		}
 		bd = key_bindings_first(table);
 		while (bd != NULL) {
+			if (only != KEYC_UNKNOWN && bd->key != only) {
+				bd = key_bindings_next(table, bd);
+				continue;
+			}
 			key = args_escape(key_string_lookup_key(bd->key));
 
 			if (bd->flags & KEY_BINDING_REPEAT)
@@ -113,6 +243,11 @@ cmd_list_keys_exec(struct cmd *self, struct cmdq_item *item)
 		}
 		bd = key_bindings_first(table);
 		while (bd != NULL) {
+			if (only != KEYC_UNKNOWN && bd->key != only) {
+				bd = key_bindings_next(table, bd);
+				continue;
+			}
+			found = 1;
 			key = args_escape(key_string_lookup_key(bd->key));
 
 			if (!repeat)
@@ -162,13 +297,18 @@ cmd_list_keys_exec(struct cmd *self, struct cmdq_item *item)
 
 	free(tmp);
 
+out:
+	if (only != KEYC_UNKNOWN && !found) {
+		cmdq_error(item, "unknown key: %s", args->argv[0]);
+		return (CMD_RETURN_ERROR);
+	}
 	return (CMD_RETURN_NORMAL);
 }
 
 static enum cmd_retval
 cmd_list_keys_commands(struct cmd *self, struct cmdq_item *item)
 {
-	struct args		*args = self->args;
+	struct args		 *args = self->args;
 	const struct cmd_entry	**entryp;
 	const struct cmd_entry	 *entry;
 	struct format_tree	 *ft;
diff --git a/key-bindings.c b/key-bindings.c
index 94110a49..4387c011 100644
--- a/key-bindings.c
+++ b/key-bindings.c
@@ -90,6 +90,7 @@ key_bindings_free(struct key_table *table, struct key_binding *bd)
 {
 	RB_REMOVE(key_bindings, &table->key_bindings, bd);
 	cmd_list_free(bd->cmdlist);
+	free((void *)bd->note);
 	free(bd);
 }
 
@@ -163,7 +164,7 @@ key_bindings_next(__unused struct key_table *table, struct key_binding *bd)
 }
 
 void
-key_bindings_add(const char *name, key_code key, int repeat,
+key_bindings_add(const char *name, key_code key, const char *note, int repeat,
     struct cmd_list *cmdlist)
 {
 	struct key_table	*table;
@@ -177,6 +178,8 @@ key_bindings_add(const char *name, key_code key, int repeat,
 
 	bd = xcalloc(1, sizeof *bd);
 	bd->key = key;
+	if (note != NULL)
+		bd->note = xstrdup(note);
 	RB_INSERT(key_bindings, &table->key_bindings, bd);
 
 	if (repeat)
@@ -226,87 +229,88 @@ void
 key_bindings_init(void)
 {
 	static const char *defaults[] = {
-		"bind C-b send-prefix",
-		"bind C-o rotate-window",
-		"bind C-z suspend-client",
-		"bind Space next-layout",
-		"bind ! break-pane",
-		"bind '\"' split-window",
-		"bind '#' list-buffers",
-		"bind '$' command-prompt -I'#S' \"rename-session -- '%%'\"",
-		"bind % split-window -h",
-		"bind & confirm-before -p\"kill-window #W? (y/n)\" kill-window",
-		"bind \"'\" command-prompt -pindex \"select-window -t ':%%'\"",
-		"bind ( switch-client -p",
-		"bind ) switch-client -n",
-		"bind , command-prompt -I'#W' \"rename-window -- '%%'\"",
-		"bind - delete-buffer",
-		"bind . command-prompt \"move-window -t '%%'\"",
-		"bind 0 select-window -t:=0",
-		"bind 1 select-window -t:=1",
-		"bind 2 select-window -t:=2",
-		"bind 3 select-window -t:=3",
-		"bind 4 select-window -t:=4",
-		"bind 5 select-window -t:=5",
-		"bind 6 select-window -t:=6",
-		"bind 7 select-window -t:=7",
-		"bind 8 select-window -t:=8",
-		"bind 9 select-window -t:=9",
-		"bind : command-prompt",
-		"bind \\; last-pane",
-		"bind = choose-buffer -Z",
-		"bind ? list-keys",
-		"bind D choose-client -Z",
-		"bind E select-layout -E",
-		"bind L switch-client -l",
-		"bind M select-pane -M",
-		"bind [ copy-mode",
-		"bind ] paste-buffer",
-		"bind c new-window",
-		"bind d detach-client",
-		"bind f command-prompt \"find-window -Z -- '%%'\"",
-		"bind i display-message",
-		"bind l last-window",
-		"bind m select-pane -m",
-		"bind n next-window",
-		"bind o select-pane -t:.+",
-		"bind p previous-window",
-		"bind q display-panes",
-		"bind r refresh-client",
-		"bind s choose-tree -Zs",
-		"bind t clock-mode",
-		"bind w choose-tree -Zw",
-		"bind x confirm-before -p\"kill-pane #P? (y/n)\" kill-pane",
-		"bind z resize-pane -Z",
-		"bind '{' swap-pane -U",
-		"bind '}' swap-pane -D",
-		"bind '~' show-messages",
-		"bind PPage copy-mode -u",
-		"bind -r Up select-pane -U",
-		"bind -r Down select-pane -D",
-		"bind -r Left select-pane -L",
-		"bind -r Right select-pane -R",
-		"bind M-1 select-layout even-horizontal",
-		"bind M-2 select-layout even-vertical",
-		"bind M-3 select-layout main-horizontal",
-		"bind M-4 select-layout main-vertical",
-		"bind M-5 select-layout tiled",
-		"bind M-n next-window -a",
-		"bind M-o rotate-window -D",
-		"bind M-p previous-window -a",
-		"bind -r S-Up refresh-client -U 10",
-		"bind -r S-Down refresh-client -D 10",
-		"bind -r S-Left refresh-client -L 10",
-		"bind -r S-Right refresh-client -R 10",
-		"bind -r DC refresh-client -c",
-		"bind -r M-Up resize-pane -U 5",
-		"bind -r M-Down resize-pane -D 5",
-		"bind -r M-Left resize-pane -L 5",
-		"bind -r M-Right resize-pane -R 5",
-		"bind -r C-Up resize-pane -U",
-		"bind -r C-Down resize-pane -D",
-		"bind -r C-Left resize-pane -L",
-		"bind -r C-Right resize-pane -R",
+		"bind -N 'Send the prefix key' C-b send-prefix",
+		"bind -N 'Rotate through the panes' C-o rotate-window",
+		"bind -N 'Suspend the current client' C-z suspend-client",
+		"bind -N 'Select next layout' Space next-layout",
+		"bind -N 'Break pane to a new window' ! break-pane",
+		"bind -N 'Split window vertically' '\"' split-window",
+		"bind -N 'List all paste buffers' '#' list-buffers",
+		"bind -N 'Rename current session' '$' command-prompt -I'#S' \"rename-session -- '%%'\"",
+		"bind -N 'Split window horizontally' % split-window -h",
+		"bind -N 'Kill current window' & confirm-before -p\"kill-window #W? (y/n)\" kill-window",
+		"bind -N 'Prompt for window index to select' \"'\" command-prompt -pindex \"select-window -t ':%%'\"",
+		"bind -N 'Switch to previous client' ( switch-client -p",
+		"bind -N 'Switch to next client' ) switch-client -n",
+		"bind -N 'Rename current window' , command-prompt -I'#W' \"rename-window -- '%%'\"",
+		"bind -N 'Delete the most recent paste buffer' - delete-buffer",
+		"bind -N 'Move the current window' . command-prompt \"move-window -t '%%'\"",
+		"bind -N 'Describe key binding' '/' command-prompt -kpkey 'list-keys -1N \"%%%\"'",
+		"bind -N 'Select window 0' 0 select-window -t:=0",
+		"bind -N 'Select window 1' 1 select-window -t:=1",
+		"bind -N 'Select window 2' 2 select-window -t:=2",
+		"bind -N 'Select window 3' 3 select-window -t:=3",
+		"bind -N 'Select window 4' 4 select-window -t:=4",
+		"bind -N 'Select window 5' 5 select-window -t:=5",
+		"bind -N 'Select window 6' 6 select-window -t:=6",
+		"bind -N 'Select window 7' 7 select-window -t:=7",
+		"bind -N 'Select window 8' 8 select-window -t:=8",
+		"bind -N 'Select window 9' 9 select-window -t:=9",
+		"bind -N 'Prompt for a command' : command-prompt",
+		"bind -N 'Move to the previously active pane' \\; last-pane",
+		"bind -N 'Choose a paste buffer from a list' = choose-buffer -Z",
+		"bind -N 'List key bindings' ? list-keys -N",
+		"bind -N 'Choose a client from a list' D choose-client -Z",
+		"bind -N 'Spread panes out evenly' E select-layout -E",
+		"bind -N 'Switch to the last client' L switch-client -l",
+		"bind -N 'Clear the marked pane' M select-pane -M",
+		"bind -N 'Enter copy mode' [ copy-mode",
+		"bind -N 'Paste the most recent paste buffer' ] paste-buffer",
+		"bind -N 'Create a new window' c new-window",
+		"bind -N 'Detach the current client' d detach-client",
+		"bind -N 'Search for a pane' f command-prompt \"find-window -Z -- '%%'\"",
+		"bind -N 'Display window information' i display-message",
+		"bind -N 'Select the previously current window' l last-window",
+		"bind -N 'Toggle the marked pane' m select-pane -m",
+		"bind -N 'Select the next window' n next-window",
+		"bind -N 'Select the next pane' o select-pane -t:.+",
+		"bind -N 'Select the previous pane' p previous-window",
+		"bind -N 'Display pane numbers' q display-panes",
+		"bind -N 'Redraw the current client' r refresh-client",
+		"bind -N 'Choose a session from a list' s choose-tree -Zs",
+		"bind -N 'Show a clock' t clock-mode",
+		"bind -N 'Choose a window from a list' w choose-tree -Zw",
+		"bind -N 'Kill the active pane' x confirm-before -p\"kill-pane #P? (y/n)\" kill-pane",
+		"bind -N 'Zoom the active pane' z resize-pane -Z",
+		"bind -N 'Swap the active pane with the pane above' '{' swap-pane -U",
+		"bind -N 'Swap the active pane with the pane below' '}' swap-pane -D",
+		"bind -N 'Show messages' '~' show-messages",
+		"bind -N 'Enter copy mode and scroll up' PPage copy-mode -u",
+		"bind -N 'Select the pane above the active pane' -r Up select-pane -U",
+		"bind -N 'Select the pane below the active pane' -r Down select-pane -D",
+		"bind -N 'Select the pane to the left of the active pane' -r Left select-pane -L",
+		"bind -N 'Select the pane to the right of the active pane' -r Right select-pane -R",
+		"bind -N 'Set the even-horizontal layout' M-1 select-layout even-horizontal",
+		"bind -N 'Set the even-vertical layout' M-2 select-layout even-vertical",
+		"bind -N 'Set the main-horizontal layout' M-3 select-layout main-horizontal",
+		"bind -N 'Set the main-vertical layout' M-4 select-layout main-vertical",
+		"bind -N 'Select the tiled layout' M-5 select-layout tiled",
+		"bind -N 'Select the next window with an alert' M-n next-window -a",
+		"bind -N 'Rotate through the panes in reverse' M-o rotate-window -D",
+		"bind -N 'Select the previous window with an alert' M-p previous-window -a",
+		"bind -N 'Move the visible part of the window up' -r S-Up refresh-client -U 10",
+		"bind -N 'Move the visible part of the window down' -r S-Down refresh-client -D 10",
+		"bind -N 'Move the visible part of the window left' -r S-Left refresh-client -L 10",
+		"bind -N 'Move the visible part of the window right' -r S-Right refresh-client -R 10",
+		"bind -N 'Reset so the visible part of the window follows the cursor' -r DC refresh-client -c",
+		"bind -N 'Resize the pane up by 5' -r M-Up resize-pane -U 5",
+		"bind -N 'Resize the pane down by 5' -r M-Down resize-pane -D 5",
+		"bind -N 'Resize the pane left by 5' -r M-Left resize-pane -L 5",
+		"bind -N 'Resize the pane right by 5' -r M-Right resize-pane -R 5",
+		"bind -N 'Resize the pane up' -r C-Up resize-pane -U",
+		"bind -N 'Resize the pane down' -r C-Down resize-pane -D",
+		"bind -N 'Resize the pane left' -r C-Left resize-pane -L",
+		"bind -N 'Resize the pane right' -r C-Right resize-pane -R",
 
 		"bind -n MouseDown1Pane select-pane -t=\\; send-keys -M",
 		"bind -n MouseDrag1Border resize-pane -M",
diff --git a/status.c b/status.c
index 0f96f0d3..33f6c47a 100644
--- a/status.c
+++ b/status.c
@@ -915,11 +915,17 @@ status_prompt_key(struct client *c, key_code key)
 {
 	struct options		*oo = c->session->options;
 	char			*s, *cp, word[64], prefix = '=';
-	const char		*histstr, *ws = NULL;
+	const char		*histstr, *ws = NULL, *keystring;
 	size_t			 size, n, off, idx, used;
 	struct utf8_data	 tmp, *first, *last, *ud;
 	int			 keys;
 
+	if (c->prompt_flags & PROMPT_KEY) {
+		keystring = key_string_lookup_key(key);
+		c->prompt_inputcb(c, c->prompt_data, keystring, 1);
+		status_prompt_clear(c);
+		return (0);
+	}
 	size = utf8_strlen(c->prompt_buffer);
 
 	if (c->prompt_flags & PROMPT_NUMERIC) {
diff --git a/tmux.1 b/tmux.1
index eb5087be..4a618186 100644
--- a/tmux.1
+++ b/tmux.1
@@ -551,7 +551,7 @@ Braces may be enclosed inside braces, for example:
 .Bd -literal -offset indent
 bind x if-shell "true" {
     if-shell "true" {
-         display "true!"
+        display "true!"
     }
 }
 .Ed
@@ -1335,7 +1335,8 @@ is used,
 option will not be applied.
 .Pp
 .Fl T
-sets the client's key table; the next key from the client will be interpreted from
+sets the client's key table; the next key from the client will be interpreted
+from
 .Ar key-table .
 This may be used to configure multiple prefix keys, or to bind commands to
 sequences of keys.
@@ -2613,6 +2614,7 @@ Commands related to key bindings are as follows:
 .Bl -tag -width Ds
 .It Xo Ic bind-key
 .Op Fl nr
+.Op Fl N Ar note
 .Op Fl T Ar key-table
 .Ar key Ar command Op Ar arguments
 .Xc
@@ -2660,22 +2662,46 @@ The
 flag indicates this key may repeat, see the
 .Ic repeat-time
 option.
+.Fl N
+attaches a note to the key (shown with
+.Ic list-keys
+.Fl N ) .
 .Pp
 To view the default bindings and possible commands, see the
 .Ic list-keys
 command.
 .It Xo Ic list-keys
-.Op Fl T Ar key-table
+.Op Fl 1N
+.Op Fl P Ar prefix-string Fl T Ar key-table
+.Op key
 .Xc
 .D1 (alias: Ic lsk )
 List all key bindings.
-Without
-.Fl T
-all key tables are printed.
+By default this shows all keys or any bindings for
+.Ar key
+in the syntax of the
+.Ic bind-key
+command.
+.Fl N
+instead show keys and attached notes, i
+.Ar key-table
+if given or in the
+.Em root
+and
+.Em prefix
+key tables by default.
+.Fl P
+specifies a prefix to print before each key.
 With
+.Fl 1
+only the first matching key and note is shown.
+.Pp
+Without
+.Fl N ,
 .Fl T
-only
-.Ar key-table .
+prints only keys in
+.Ar key-table ,
+otherwise all key tables are printed.
 .It Xo Ic send-keys
 .Op Fl FHlMRX
 .Op Fl N Ar repeat-count
@@ -4693,7 +4719,7 @@ session option.
 Commands related to the status line are as follows:
 .Bl -tag -width Ds
 .It Xo Ic command-prompt
-.Op Fl 1Ni
+.Op Fl 1ikN
 .Op Fl I Ar inputs
 .Op Fl p Ar prompts
 .Op Fl t Ar target-client
@@ -4743,6 +4769,10 @@ but any quotation marks are escaped.
 .Fl 1
 makes the prompt only accept one key press, in this case the resulting input
 is a single character.
+.Fl k
+is like
+.Fl 1
+but the key press is translated to a key name.
 .Fl N
 makes the prompt only accept numeric key presses.
 .Fl i
diff --git a/tmux.h b/tmux.h
index ac555be5..093f17a4 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1609,6 +1609,7 @@ struct client {
 #define PROMPT_NUMERIC 0x2
 #define PROMPT_INCREMENTAL 0x4
 #define PROMPT_NOFORMAT 0x8
+#define PROMPT_KEY 0x10
 	int		 prompt_flags;
 
 	struct session	*session;
@@ -1636,6 +1637,7 @@ TAILQ_HEAD(clients, client);
 struct key_binding {
 	key_code		 key;
 	struct cmd_list		*cmdlist;
+	const char		*note;
 
 	int			 flags;
 #define KEY_BINDING_REPEAT 0x1
@@ -2147,7 +2149,8 @@ void	 key_bindings_unref_table(struct key_table *);
 struct key_binding *key_bindings_get(struct key_table *, key_code);
 struct key_binding *key_bindings_first(struct key_table *);
 struct key_binding *key_bindings_next(struct key_table *, struct key_binding *);
-void	 key_bindings_add(const char *, key_code, int, struct cmd_list *);
+void	 key_bindings_add(const char *, key_code, const char *, int,
+	     struct cmd_list *);
 void	 key_bindings_remove(const char *, key_code);
 void	 key_bindings_remove_table(const char *);
 void	 key_bindings_init(void);

From 2c38e01b548553aa162f9f126147b5ed64fd1700 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Mon, 27 Jan 2020 09:04:47 +0000
Subject: [PATCH 15/29] Expand description of start-server.

---
 tmux.1 | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/tmux.1 b/tmux.1
index 4a618186..11bdf4bc 100644
--- a/tmux.1
+++ b/tmux.1
@@ -1287,6 +1287,17 @@ shows the parsed commands and line numbers if possible.
 Start the
 .Nm
 server, if not already running, without creating any sessions.
+.Pp
+Note that as by default the
+.Nm
+server will exit with no sessions, this is only useful if a session is created in
+.Pa ~/.tmux.conf ,
+.Ic exit-empty
+is turned off, or another command is run as part of the same command sequence.
+For example:
+.Bd -literal -offset indent
+$ tmux start \\; show -g
+.Ed
 .It Xo Ic suspend-client
 .Op Fl t Ar target-client
 .Xc

From 24350879cdfb9ef23dee0da409b621e9830d8baf Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Tue, 28 Jan 2020 08:06:11 +0000
Subject: [PATCH 16/29] Add a define for flags meaning a client is not
 attached, and fix unattached counter, reported by Thomas Sattler.

---
 resize.c        | 5 +++--
 server-client.c | 4 ++--
 tmux.h          | 4 ++++
 window-client.c | 2 +-
 4 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/resize.c b/resize.c
index 054b025f..b4142a70 100644
--- a/resize.c
+++ b/resize.c
@@ -363,14 +363,15 @@ recalculate_sizes(void)
 	 * client.
 	 */
 	TAILQ_FOREACH(c, &clients, entry) {
+		s = c->session;
+		if (s != NULL && !(c->flags & CLIENT_UNATTACHEDFLAGS))
+			s->attached++;
 		if (ignore_client_size(c))
 			continue;
-		s = c->session;
 		if (c->tty.sy <= s->statuslines || (c->flags & CLIENT_CONTROL))
 			c->flags |= CLIENT_STATUSOFF;
 		else
 			c->flags &= ~CLIENT_STATUSOFF;
-		s->attached++;
 	}
 
 	/* Walk each window and adjust the size. */
diff --git a/server-client.c b/server-client.c
index ee7b4c70..12e07327 100644
--- a/server-client.c
+++ b/server-client.c
@@ -1034,7 +1034,7 @@ server_client_key_callback(struct cmdq_item *item, void *data)
 	key_code			 key0;
 
 	/* Check the client is good to accept input. */
-	if (s == NULL || (c->flags & (CLIENT_DEAD|CLIENT_SUSPENDED)) != 0)
+	if (s == NULL || (c->flags & CLIENT_UNATTACHEDFLAGS))
 		goto out;
 	wl = s->curw;
 
@@ -1221,7 +1221,7 @@ server_client_handle_key(struct client *c, struct key_event *event)
 	struct cmdq_item	*item;
 
 	/* Check the client is good to accept input. */
-	if (s == NULL || (c->flags & (CLIENT_DEAD|CLIENT_SUSPENDED)) != 0)
+	if (s == NULL || (c->flags & CLIENT_UNATTACHEDFLAGS))
 		return (0);
 
 	/*
diff --git a/tmux.h b/tmux.h
index 093f17a4..d56c5fea 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1582,6 +1582,10 @@ struct client {
 	 CLIENT_REDRAWSTATUSALWAYS|	\
 	 CLIENT_REDRAWBORDERS|		\
 	 CLIENT_REDRAWOVERLAY)
+#define CLIENT_UNATTACHEDFLAGS	\
+	(CLIENT_DEAD|		\
+	 CLIENT_SUSPENDED|	\
+	 CLIENT_DETACHING)
 #define CLIENT_NOSIZEFLAGS	\
 	(CLIENT_DEAD|		\
 	 CLIENT_SUSPENDED|	\
diff --git a/window-client.c b/window-client.c
index 22a0f2e2..4688cbf3 100644
--- a/window-client.c
+++ b/window-client.c
@@ -210,7 +210,7 @@ window_client_draw(__unused void *modedata, void *itemdata,
 	struct window_pane		*wp;
 	u_int				 cx = s->cx, cy = s->cy, lines, at;
 
-	if (c->session == NULL || (c->flags & (CLIENT_DEAD|CLIENT_DETACHING)))
+	if (c->session == NULL || (c->flags & CLIENT_UNATTACHEDFLAGS))
 		return;
 	wp = c->session->curw->window->active;
 

From 32816eaebd4ccd712cc7f7291a587146d122a9ff Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Tue, 28 Jan 2020 10:21:21 +0000
Subject: [PATCH 17/29] Set up working directory before killing the existing
 pane on respawn.

---
 spawn.c | 35 ++++++++++++++++++-----------------
 1 file changed, 18 insertions(+), 17 deletions(-)

diff --git a/spawn.c b/spawn.c
index 75995221..933f0c6a 100644
--- a/spawn.c
+++ b/spawn.c
@@ -225,6 +225,17 @@ spawn_pane(struct spawn_context *sc, char **cause)
 
 	spawn_log(__func__, sc);
 
+	/*
+	 * Work out the current working directory. If respawning, use
+	 * the pane's stored one unless specified.
+	 */
+	if (sc->cwd != NULL)
+		cwd = format_single(item, sc->cwd, c, s, NULL, NULL);
+	else if (~sc->flags & SPAWN_RESPAWN)
+		cwd = xstrdup(server_client_get_cwd(c, s));
+	else
+		cwd = NULL;
+
 	/*
 	 * If we are respawning then get rid of the old process. Otherwise
 	 * either create a new cell or assign to the one we are given.
@@ -235,6 +246,7 @@ spawn_pane(struct spawn_context *sc, char **cause)
 			window_pane_index(sc->wp0, &idx);
 			xasprintf(cause, "pane %s:%d.%u still active",
 			    s->name, sc->wl->idx, idx);
+			free(cwd);
 			return (NULL);
 		}
 		if (sc->wp0->fd != -1) {
@@ -255,8 +267,8 @@ spawn_pane(struct spawn_context *sc, char **cause)
 	}
 
 	/*
-	 * Now we have a pane with nothing running in it ready for the new
-	 * process. Work out the command and arguments.
+	 * Now we have a pane with nothing running in it ready for the new process.
+	 * Work out the command and arguments and store the working directory.
 	 */
 	if (sc->argc == 0 && (~sc->flags & SPAWN_RESPAWN)) {
 		cmd = options_get_string(s->options, "default-command");
@@ -271,6 +283,10 @@ spawn_pane(struct spawn_context *sc, char **cause)
 		argc = sc->argc;
 		argv = sc->argv;
 	}
+	if (cwd != NULL) {
+		free(new_wp->cwd);
+		new_wp->cwd = cwd;
+	}
 
 	/*
 	 * Replace the stored arguments if there are new ones. If not, the
@@ -282,21 +298,6 @@ spawn_pane(struct spawn_context *sc, char **cause)
 		new_wp->argv = cmd_copy_argv(argc, argv);
 	}
 
-	/*
-	 * Work out the current working directory. If respawning, use
-	 * the pane's stored one unless specified.
-	 */
-	if (sc->cwd != NULL)
-		cwd = format_single(item, sc->cwd, c, s, NULL, NULL);
-	else if (~sc->flags & SPAWN_RESPAWN)
-		cwd = xstrdup(server_client_get_cwd(c, s));
-	else
-		cwd = NULL;
-	if (cwd != NULL) {
-		free(new_wp->cwd);
-		new_wp->cwd = cwd;
-	}
-
 	/* Create an environment for this pane. */
 	child = environ_for_session(s, 0);
 	if (sc->environ != NULL)

From f165221dc4641837ee9f589bb666d310a495904c Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Tue, 28 Jan 2020 10:44:30 +0000
Subject: [PATCH 18/29] Reduce a difference with portable tmux by adding the -V
 flag and #{version} format; on OpenBSD these just report the OpenBSD version.

---
 format.c |  1 +
 proc.c   |  4 ++--
 tmux.1   |  8 +++++++-
 tmux.c   | 20 +++++++++++++++++++-
 tmux.h   |  1 +
 5 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/format.c b/format.c
index f5e7b2ce..ff8e3c62 100644
--- a/format.c
+++ b/format.c
@@ -1106,6 +1106,7 @@ format_create(struct client *c, struct cmdq_item *item, int tag, int flags)
 	ft->flags = flags;
 	ft->time = time(NULL);
 
+	format_add(ft, "version", "%s", getversion());
 	format_add_cb(ft, "host", format_cb_host);
 	format_add_cb(ft, "host_short", format_cb_host_short);
 	format_add_cb(ft, "pid", format_cb_pid);
diff --git a/proc.c b/proc.c
index 48e0d90c..3fc190a2 100644
--- a/proc.c
+++ b/proc.c
@@ -182,8 +182,8 @@ proc_start(const char *name)
 	if (uname(&u) < 0)
 		memset(&u, 0, sizeof u);
 
-	log_debug("%s started (%ld): socket %s, protocol %d", name,
-	    (long)getpid(), socket_path, PROTOCOL_VERSION);
+	log_debug("%s started (%ld): version %s, socket %s, protocol %d", name,
+	    (long)getpid(), getversion(), socket_path, PROTOCOL_VERSION);
 	log_debug("on %s %s %s; libevent %s (%s)", u.sysname, u.release,
 	    u.version, event_get_version(), event_get_method());
 
diff --git a/tmux.1 b/tmux.1
index 11bdf4bc..bc24c193 100644
--- a/tmux.1
+++ b/tmux.1
@@ -23,7 +23,7 @@
 .Sh SYNOPSIS
 .Nm tmux
 .Bk -words
-.Op Fl 2Cluv
+.Op Fl 2CluvV
 .Op Fl c Ar shell-command
 .Op Fl f Ar file
 .Op Fl L Ar socket-name
@@ -210,6 +210,11 @@ signal may be sent to the
 server process to toggle logging between on (as if
 .Fl v
 was given) and off.
+.It Fl V
+Report the
+.Nm
+version.
+.Pp
 .It Ar command Op Ar flags
 This specifies one of a set of commands used to control
 .Nm ,
@@ -4369,6 +4374,7 @@ The following variables are available, where appropriate:
 .It Li "session_windows" Ta "" Ta "Number of windows in session"
 .It Li "socket_path" Ta "" Ta "Server socket path"
 .It Li "start_time" Ta "" Ta "Server start time"
+.It Li "version" Ta "" Ta "Server version"
 .It Li "window_active" Ta "" Ta "1 if window active"
 .It Li "window_active_clients" Ta "" Ta "Number of clients viewing this window"
 .It Li "window_active_clients_list" Ta "" Ta "List of clients viewing this window"
diff --git a/tmux.c b/tmux.c
index fe2647f5..f98037b5 100644
--- a/tmux.c
+++ b/tmux.c
@@ -18,6 +18,7 @@
 
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/utsname.h>
 
 #include <err.h>
 #include <errno.h>
@@ -212,6 +213,20 @@ find_home(void)
 	return (home);
 }
 
+const char *
+getversion(void)
+{
+	static char	*version;
+	struct utsname	 u;
+
+	if (version == NULL) {
+		if (uname(&u) < 0)
+			fatalx("uname failed");
+		xasprintf(&version, "openbsd-%s", u.release);
+	}
+	return version;
+}
+
 int
 main(int argc, char **argv)
 {
@@ -238,7 +253,7 @@ main(int argc, char **argv)
 		flags = 0;
 
 	label = path = NULL;
-	while ((opt = getopt(argc, argv, "2c:Cdf:lL:qS:uUv")) != -1) {
+	while ((opt = getopt(argc, argv, "2c:Cdf:lL:qS:uUvV")) != -1) {
 		switch (opt) {
 		case '2':
 			flags |= CLIENT_256COLOURS;
@@ -255,6 +270,9 @@ main(int argc, char **argv)
 		case 'f':
 			set_cfg_file(optarg);
 			break;
+ 		case 'V':
+			printf("%s %s\n", getprogname(), getversion());
+ 			exit(0);
 		case 'l':
 			flags |= CLIENT_LOGIN;
 			break;
diff --git a/tmux.h b/tmux.h
index d56c5fea..24e4277f 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1769,6 +1769,7 @@ int		 areshell(const char *);
 void		 setblocking(int, int);
 const char	*find_cwd(void);
 const char	*find_home(void);
+const char	*getversion(void);
 
 /* proc.c */
 struct imsg;

From 90e962fff8f4d251cdf7fcc653caa34973c82d91 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Tue, 28 Jan 2020 10:59:29 +0000
Subject: [PATCH 19/29] Add support for the iTerm2 DSR 1337 sequence to get the
 terminal version.

---
 input.c    | 9 +++++++++
 tty-keys.c | 2 +-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/input.c b/input.c
index 452eac7f..d7071bfe 100644
--- a/input.c
+++ b/input.c
@@ -20,6 +20,7 @@
 
 #include <netinet/in.h>
 
+#include <ctype.h>
 #include <resolv.h>
 #include <stdlib.h>
 #include <string.h>
@@ -1301,6 +1302,7 @@ input_csi_dispatch(struct input_ctx *ictx)
 	struct input_table_entry       *entry;
 	int				i, n, m;
 	u_int				cx, bg = ictx->cell.cell.bg;
+	char			       *copy, *cp;
 
 	if (ictx->flags & INPUT_DISCARD)
 		return (0);
@@ -1432,6 +1434,13 @@ input_csi_dispatch(struct input_ctx *ictx)
 		case 6:
 			input_reply(ictx, "\033[%u;%uR", s->cy + 1, s->cx + 1);
 			break;
+		case 1337: /* Terminal version, from iTerm2. */
+			copy = xstrdup(getversion());
+			for (cp = copy; *cp != '\0'; cp++)
+				*cp = toupper((u_char)*cp);
+			input_reply(ictx, "\033[TMUX %sn", copy);
+			free(copy);
+			break;
 		default:
 			log_debug("%s: unknown '%c'", __func__, ictx->ch);
 			break;
diff --git a/tty-keys.c b/tty-keys.c
index 968f67ca..987fd1b0 100644
--- a/tty-keys.c
+++ b/tty-keys.c
@@ -1099,7 +1099,7 @@ tty_keys_device_status_report(struct tty *tty, const char *buf, size_t len,
 		return (-1);
 	if (len == 2)
 		return (1);
-	if (buf[2] != 'I')
+	if (buf[2] != 'I' && buf[2] != 'T')
 		return (-1);
 	if (len == 3)
 		return (1);

From 685eb381dec7fc741a15ce11a84d8c96ed66ce42 Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicholas.marriott@gmail.com>
Date: Tue, 28 Jan 2020 11:28:30 +0000
Subject: [PATCH 20/29] Fix for version changes.

---
 Makefile.am |  5 +++--
 input.c     |  1 +
 tmux.c      | 13 +------------
 3 files changed, 5 insertions(+), 14 deletions(-)

diff --git a/Makefile.am b/Makefile.am
index 6902477e..082a467c 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -11,8 +11,9 @@ EXTRA_DIST = \
 dist_EXTRA_tmux_SOURCES = compat/*.[ch]
 
 # Preprocessor flags.
-AM_CPPFLAGS += @XOPEN_DEFINES@
-AM_CPPFLAGS += -DTMUX_CONF="\"$(sysconfdir)/tmux.conf:~/.tmux.conf:~/.config/tmux/tmux.conf\""
+AM_CPPFLAGS += @XOPEN_DEFINES@ \
+	-DTMUX_VERSION="\"@VERSION@\"" \
+	-DTMUX_CONF="\"$(sysconfdir)/tmux.conf:~/.tmux.conf:~/.config/tmux/tmux.conf\""
 
 # Additional object files.
 LDADD = $(LIBOBJS)
diff --git a/input.c b/input.c
index 452eac7f..a2c63e14 100644
--- a/input.c
+++ b/input.c
@@ -20,6 +20,7 @@
 
 #include <netinet/in.h>
 
+#include <ctype.h>
 #include <resolv.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/tmux.c b/tmux.c
index b5cdfbf9..3c1feccc 100644
--- a/tmux.c
+++ b/tmux.c
@@ -213,15 +213,7 @@ find_home(void)
 const char *
 getversion(void)
 {
-	static char	*version;
-	struct utsname	 u;
-
-	if (version == NULL) {
-		if (uname(&u) < 0)
-			fatalx("uname failed");
-		xasprintf(&version, "openbsd-%s", u.release);
-	}
-	return version;
+	return TMUX_VERSION;
 }
 
 int
@@ -264,9 +256,6 @@ main(int argc, char **argv)
 			else
 				flags |= CLIENT_CONTROL;
 			break;
-		case 'V':
-			printf("%s %s\n", getprogname(), VERSION);
-			exit(0);
 		case 'f':
 			set_cfg_file(optarg);
 			break;

From 84995ae1726589b5fb04e002e43496775e0ebfcd Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Tue, 28 Jan 2020 11:31:31 +0000
Subject: [PATCH 21/29] -V also needs to go in usage.

---
 tmux.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tmux.c b/tmux.c
index f98037b5..6572ad4e 100644
--- a/tmux.c
+++ b/tmux.c
@@ -56,7 +56,7 @@ static __dead void
 usage(void)
 {
 	fprintf(stderr,
-	    "usage: %s [-2Cluv] [-c shell-command] [-f file] [-L socket-name]\n"
+	    "usage: %s [-2CluvV] [-c shell-command] [-f file] [-L socket-name]\n"
 	    "            [-S socket-path] [command [flags]]\n",
 	    getprogname());
 	exit(1);

From a6129e99749d2bbc8b4a991c7b5d09300aa55f39 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Tue, 28 Jan 2020 11:39:51 +0000
Subject: [PATCH 22/29] If we can identify the terminal as iTerm2 or as tmux,
 we can be sure they support 256 and RGB colours, so set those flags too.

---
 tmux.h     |  1 +
 tty-keys.c |  4 +++-
 tty-term.c | 28 +++++++++-------------------
 tty.c      | 27 +++++++++++++++------------
 4 files changed, 28 insertions(+), 32 deletions(-)

diff --git a/tmux.h b/tmux.h
index 24e4277f..3ec89019 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1171,6 +1171,7 @@ struct tty_term {
 #define TERM_NOXENL 0x2
 #define TERM_DECSLRM 0x4
 #define TERM_DECFRA 0x8
+#define TERM_RGBCOLOURS 0x10
 	int		 flags;
 
 	LIST_ENTRY(tty_term) entry;
diff --git a/tty-keys.c b/tty-keys.c
index 987fd1b0..064f2172 100644
--- a/tty-keys.c
+++ b/tty-keys.c
@@ -1117,7 +1117,9 @@ tty_keys_device_status_report(struct tty *tty, const char *buf, size_t len,
 
 	/* Set terminal flags. */
 	if (strncmp(tmp, "ITERM2 ", 7) == 0)
-		flags |= TERM_DECSLRM;
+		flags |= (TERM_DECSLRM|TERM_256COLOURS|TERM_RGBCOLOURS);
+	if (strncmp(tmp, "TMUX ", 5) == 0)
+		flags |= (TERM_256COLOURS|TERM_RGBCOLOURS);
 	log_debug("%s: received DSR %.*s", c->name, (int)*size, buf);
 
 	tty_set_flags(tty, flags);
diff --git a/tty-term.c b/tty-term.c
index 164ab2f1..ef7d7905 100644
--- a/tty-term.c
+++ b/tty-term.c
@@ -522,11 +522,16 @@ tty_term_find(char *name, int fd, char **cause)
 		goto error;
 	}
 
-	/* Figure out if we have 256 colours (or more). */
-	if (tty_term_number(term, TTYC_COLORS) >= 256 ||
-	    tty_term_has(term, TTYC_RGB))
+	/* Set flag if terminal has 256 colours. */
+	if (tty_term_number(term, TTYC_COLORS) >= 256)
 		term->flags |= TERM_256COLOURS;
 
+	/* Set flag if terminal has RGB colours. */
+	if ((tty_term_flag(term, TTYC_TC) || tty_term_has(term, TTYC_RGB)) ||
+	    (tty_term_has(term, TTYC_SETRGBF) &&
+	    tty_term_has(term, TTYC_SETRGBB)))
+		term->flags |= TERM_RGBCOLOURS;
+
 	/*
 	 * Terminals without xenl (eat newline glitch) wrap at at $COLUMNS - 1
 	 * rather than $COLUMNS (the cursor can never be beyond $COLUMNS - 1).
@@ -561,22 +566,7 @@ tty_term_find(char *name, int fd, char **cause)
 		code->type = TTYCODE_STRING;
 	}
 
-	/*
-	 * On terminals with RGB colour (Tc or RGB), fill in setrgbf and
-	 * setrgbb if they are missing.
-	 */
-	if ((tty_term_flag(term, TTYC_TC) || tty_term_flag(term, TTYC_RGB)) &&
-	    !tty_term_has(term, TTYC_SETRGBF) &&
-	    !tty_term_has(term, TTYC_SETRGBB)) {
-		code = &term->codes[TTYC_SETRGBF];
-		code->value.string = xstrdup("\033[38;2;%p1%d;%p2%d;%p3%dm");
-		code->type = TTYCODE_STRING;
-		code = &term->codes[TTYC_SETRGBB];
-		code->value.string = xstrdup("\033[48;2;%p1%d;%p2%d;%p3%dm");
-		code->type = TTYCODE_STRING;
-	}
-
-	/* Log it. */
+	/* Log the capabilities. */
 	for (i = 0; i < tty_term_ncodes(); i++)
 		log_debug("%s%s", name, tty_term_describe(term, i));
 
diff --git a/tty.c b/tty.c
index 3d58f05b..54c3be30 100644
--- a/tty.c
+++ b/tty.c
@@ -2386,11 +2386,10 @@ tty_check_fg(struct tty *tty, struct window_pane *wp, struct grid_cell *gc)
 	/* Is this a 24-bit colour? */
 	if (gc->fg & COLOUR_FLAG_RGB) {
 		/* Not a 24-bit terminal? Translate to 256-colour palette. */
-		if (!tty_term_has(tty->term, TTYC_SETRGBF)) {
-			colour_split_rgb(gc->fg, &r, &g, &b);
-			gc->fg = colour_find_rgb(r, g, b);
-		} else
+		if ((tty->term->flags|tty->term_flags) & TERM_RGBCOLOURS)
 			return;
+		colour_split_rgb(gc->fg, &r, &g, &b);
+		gc->fg = colour_find_rgb(r, g, b);
 	}
 
 	/* How many colours does this terminal have? */
@@ -2436,11 +2435,10 @@ tty_check_bg(struct tty *tty, struct window_pane *wp, struct grid_cell *gc)
 	/* Is this a 24-bit colour? */
 	if (gc->bg & COLOUR_FLAG_RGB) {
 		/* Not a 24-bit terminal? Translate to 256-colour palette. */
-		if (!tty_term_has(tty->term, TTYC_SETRGBB)) {
-			colour_split_rgb(gc->bg, &r, &g, &b);
-			gc->bg = colour_find_rgb(r, g, b);
-		} else
+		if ((tty->term->flags|tty->term_flags) & TERM_RGBCOLOURS)
 			return;
+		colour_split_rgb(gc->bg, &r, &g, &b);
+		gc->bg = colour_find_rgb(r, g, b);
 	}
 
 	/* How many colours does this terminal have? */
@@ -2617,15 +2615,14 @@ tty_try_colour(struct tty *tty, int colour, const char *type)
 	}
 
 	if (colour & COLOUR_FLAG_RGB) {
+		colour_split_rgb(colour & 0xffffff, &r, &g, &b);
 		if (*type == '3') {
 			if (!tty_term_has(tty->term, TTYC_SETRGBF))
-				return (-1);
-			colour_split_rgb(colour & 0xffffff, &r, &g, &b);
+				goto fallback_rgb;
 			tty_putcode3(tty, TTYC_SETRGBF, r, g, b);
 		} else {
 			if (!tty_term_has(tty->term, TTYC_SETRGBB))
-				return (-1);
-			colour_split_rgb(colour & 0xffffff, &r, &g, &b);
+				goto fallback_rgb;
 			tty_putcode3(tty, TTYC_SETRGBB, r, g, b);
 		}
 		return (0);
@@ -2638,6 +2635,12 @@ fallback_256:
 	log_debug("%s: 256 colour fallback: %s", tty->client->name, s);
 	tty_puts(tty, s);
 	return (0);
+
+fallback_rgb:
+	xsnprintf(s, sizeof s, "\033[%s;2;%d;%d;%dm", type, r, g, b);
+	log_debug("%s: RGB colour fallback: %s", tty->client->name, s);
+	tty_puts(tty, s);
+	return (0);
 }
 
 static void

From e3887022604d6ee6f922cdaa274b54cdf06020ba Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Tue, 28 Jan 2020 13:10:14 +0000
Subject: [PATCH 23/29] Ignore empty commands rather than adding them to the
 command list rather than trying to skip them later, fixes problem reported by
 M Kelly.

---
 cmd-parse.y | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/cmd-parse.y b/cmd-parse.y
index 41bcdaa8..2375370b 100644
--- a/cmd-parse.y
+++ b/cmd-parse.y
@@ -341,7 +341,8 @@ commands	: command
 			struct cmd_parse_state	*ps = &parse_state;
 
 			$$ = cmd_parse_new_commands();
-			if (ps->scope == NULL || ps->scope->flag)
+			if ($1->name != NULL &&
+			    (ps->scope == NULL || ps->scope->flag))
 				TAILQ_INSERT_TAIL($$, $1, entry);
 			else
 				cmd_parse_free_command($1);
@@ -360,7 +361,8 @@ commands	: command
 		{
 			struct cmd_parse_state	*ps = &parse_state;
 
-			if (ps->scope == NULL || ps->scope->flag) {
+			if ($3->name != NULL &&
+			    (ps->scope == NULL || ps->scope->flag)) {
 				$$ = $1;
 				TAILQ_INSERT_TAIL($$, $3, entry);
 			} else {
@@ -641,8 +643,6 @@ cmd_parse_build_commands(struct cmd_parse_commands *cmds,
 	 * command list.
 	 */
 	TAILQ_FOREACH_SAFE(cmd, cmds, entry, next) {
-		if (cmd->name == NULL)
-			continue;
 		alias = cmd_get_alias(cmd->name);
 		if (alias == NULL)
 			continue;
@@ -688,8 +688,6 @@ cmd_parse_build_commands(struct cmd_parse_commands *cmds,
 	 */
 	result = cmd_list_new();
 	TAILQ_FOREACH(cmd, cmds, entry) {
-		if (cmd->name == NULL)
-			continue;
 		log_debug("%s: %u %s", __func__, cmd->line, cmd->name);
 		cmd_log_argv(cmd->argc, cmd->argv, __func__);
 

From b905c5d455b354f7210dc118f748a658f0358cd7 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Tue, 28 Jan 2020 13:23:24 +0000
Subject: [PATCH 24/29] If ALL clients are readonly, allow them to affect the
 size, suggested by Thomas Sattler.

---
 resize.c | 16 ++++++++++++++++
 tmux.h   |  3 +--
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/resize.c b/resize.c
index b4142a70..96d733f0 100644
--- a/resize.c
+++ b/resize.c
@@ -66,10 +66,26 @@ resize_window(struct window *w, u_int sx, u_int sy, int xpixel, int ypixel)
 static int
 ignore_client_size(struct client *c)
 {
+	struct client	*loop;
+
 	if (c->session == NULL)
 		return (1);
 	if (c->flags & CLIENT_NOSIZEFLAGS)
 		return (1);
+	if (c->flags & CLIENT_READONLY) {
+		/*
+		 * Ignore readonly clients if there are any attached clients
+		 * that aren't readonly.
+		 */
+		TAILQ_FOREACH (loop, &clients, entry) {
+			if (loop->session == NULL)
+				continue;
+			if (loop->flags & CLIENT_NOSIZEFLAGS)
+				continue;
+			if (~loop->flags & CLIENT_READONLY)
+				return (1);
+		}
+	}
 	if ((c->flags & CLIENT_CONTROL) && (~c->flags & CLIENT_SIZECHANGED))
 		return (1);
 	return (0);
diff --git a/tmux.h b/tmux.h
index 3ec89019..418f0a44 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1590,8 +1590,7 @@ struct client {
 #define CLIENT_NOSIZEFLAGS	\
 	(CLIENT_DEAD|		\
 	 CLIENT_SUSPENDED|	\
-	 CLIENT_DETACHING|	\
-	 CLIENT_READONLY)
+	 CLIENT_DETACHING)
 	int		 flags;
 	struct key_table *keytable;
 

From 7f3feb1896ffde7bca70ffa8db933196af7b2f91 Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicholas.marriott@gmail.com>
Date: Tue, 28 Jan 2020 15:52:04 +0000
Subject: [PATCH 25/29] Add to CHANGES.

---
 CHANGES | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/CHANGES b/CHANGES
index ae980bb0..d6806e49 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,5 +1,14 @@
 CHANGES FROM 3.0 to X.X
 
+* Add support for adding a note to a key binding (with bind-key -N) and use
+  this to add descriptions to the default key bindings. A new -N flag to
+  list-keys shows key bindings with notes. Change the default ? binding to use
+  this to show a readable summary of keys. Also extend command-prompt to return
+  the name of the key pressed and add a default binding (/) to show the note
+  for the next key pressed.
+
+* Add support for the iTerm2 DSR 1337 sequence to get the terminal version.
+
 * Treat plausible but invalid keys (like C-BSpace) as literal like any other
   unrecognised string passed to send-keys
 
@@ -12,7 +21,8 @@ CHANGES FROM 3.0 to X.X
 
 * Document client exit messages in the manual page.
 
-* Do not let read-only clients limit the size.
+* Do not let read-only clients limit the size, unless all clients are
+  read-only.
 
 * Add a number of new formats to inspect what sessions and clients a window is
   present or active in.

From 7a15d10bf4abb28e0a85e0090de9c13f80f83aaa Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Wed, 29 Jan 2020 08:28:17 +0000
Subject: [PATCH 26/29] Remove extra Pp (from jmc) and add a missing word.

---
 tmux.1 | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/tmux.1 b/tmux.1
index bc24c193..21510722 100644
--- a/tmux.1
+++ b/tmux.1
@@ -214,7 +214,6 @@ was given) and off.
 Report the
 .Nm
 version.
-.Pp
 .It Ar command Op Ar flags
 This specifies one of a set of commands used to control
 .Nm ,
@@ -4953,7 +4952,7 @@ When the
 option is reached, the oldest automatically named buffer is deleted.
 Explicitly named buffers are not subject to
 .Ic buffer-limit
-and may be deleted with
+and may be deleted with the
 .Ic delete-buffer
 command.
 .Pp

From 531daba584f55fed87ec87986a7f0b497c14626f Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Wed, 29 Jan 2020 15:07:49 +0000
Subject: [PATCH 27/29] Do not send DA and DSR again if already have a
 response.

---
 input.c | 1 +
 tty.c   | 6 ++++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/input.c b/input.c
index d7071bfe..ea9320d1 100644
--- a/input.c
+++ b/input.c
@@ -773,6 +773,7 @@ input_save_state(struct input_ctx *ictx)
 	ictx->old_mode = s->mode;
 }
 
+/* Restore screen state. */
 static void
 input_restore_state(struct input_ctx *ictx)
 {
diff --git a/tty.c b/tty.c
index 54c3be30..3bab556d 100644
--- a/tty.c
+++ b/tty.c
@@ -338,8 +338,10 @@ tty_start_tty(struct tty *tty)
 			tty->flags |= TTY_FOCUS;
 			tty_puts(tty, "\033[?1004h");
 		}
-		tty_puts(tty, "\033[c\033[1337n"); /* DA and DSR */
-
+		if (~tty->flags & TTY_HAVEDA)
+			tty_puts(tty, "\033[c");
+		if (~tty->flags & TTY_HAVEDSR)
+			tty_puts(tty, "\033[1337n");
 	} else
 		tty->flags |= (TTY_HAVEDA|TTY_HAVEDSR);
 

From 44dad918f82124272486dfd4439dd72cb969fa12 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Wed, 29 Jan 2020 16:22:32 +0000
Subject: [PATCH 28/29] Warn if a message type that is no longer used is
 received.

---
 client.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/client.c b/client.c
index a36c6471..0c2a6ee2 100644
--- a/client.c
+++ b/client.c
@@ -863,6 +863,12 @@ client_dispatch_wait(struct imsg *imsg)
 	case MSG_WRITE_CLOSE:
 		client_write_close(data, datalen);
 		break;
+	case MSG_OLDSTDERR:
+	case MSG_OLDSTDIN:
+	case MSG_OLDSTDOUT:
+		fprintf(stderr, "server version is too old for client\n");
+		proc_exit(client_proc);
+		break;
 	}
 }
 

From 339832b92c298538f398754f6d3fc21d15d13326 Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicholas.marriott@gmail.com>
Date: Thu, 30 Jan 2020 09:04:51 +0000
Subject: [PATCH 29/29] Bad merge.

---
 tty-keys.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tty-keys.c b/tty-keys.c
index e6f00b2e..8cc90a08 100644
--- a/tty-keys.c
+++ b/tty-keys.c
@@ -1068,7 +1068,6 @@ tty_keys_device_attributes(struct tty *tty, const char *buf, size_t len,
 		if (p[i] == 4)
 			flags |= TERM_SIXEL;
 	}
-	tty_set_type(tty, type, flags);
 
 	tty_set_flags(tty, flags);
 	tty->flags |= TTY_HAVEDA;