From d705471aa5aa5a54f6f1749d27424ae0d137ccdf Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicholas.marriott@gmail.com>
Date: Tue, 14 Jul 2026 18:18:52 +0100
Subject: [PATCH] Regression tests for display-panes changes.

---
 regress/display-panes.sh | 254 +++++++++++++++++++++++++++++++++++++++
 regress/mode-kill.sh     |  13 +-
 2 files changed, 265 insertions(+), 2 deletions(-)
 create mode 100644 regress/display-panes.sh

diff --git a/regress/display-panes.sh b/regress/display-panes.sh
new file mode 100644
index 000000000..83d21848b
--- /dev/null
+++ b/regress/display-panes.sh
@@ -0,0 +1,254 @@
+#!/bin/sh
+
+# Tests for display-panes as panes-mode.
+
+PATH=/bin:/usr/bin
+TERM=screen
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+TMP=$(mktemp -d) || exit 1
+TMUX_TMPDIR="$TMP"
+export TMUX_TMPDIR
+TMUX="$TEST_TMUX -LtestA$$ -f/dev/null"
+TMUX2="$TEST_TMUX -LtestB$$ -f/dev/null"
+
+cleanup()
+{
+	$TMUX kill-server 2>/dev/null
+	$TMUX2 kill-server 2>/dev/null
+	rm -rf "$TMP"
+}
+trap cleanup EXIT
+
+fail()
+{
+	echo "$1" >&2
+	exit 1
+}
+
+wait_format()
+{
+	target=$1
+	format=$2
+	want=$3
+
+	i=0
+	while [ "$i" -lt 50 ]; do
+		got=$($TMUX display-message -p -t "$target" "$format" 2>/dev/null)
+		[ "$got" = "$want" ] && return 0
+		sleep 0.2
+		i=$((i + 1))
+	done
+	fail "$target: expected '$want' for $format, got '$got'"
+}
+
+wait_option()
+{
+	option=$1
+	want=$2
+
+	i=0
+	while [ "$i" -lt 50 ]; do
+		got=$($TMUX show -gv "$option" 2>/dev/null)
+		[ "$got" = "$want" ] && return 0
+		sleep 0.2
+		i=$((i + 1))
+	done
+	fail "$option: expected '$want', got '$got'"
+}
+
+wait_clients()
+{
+	i=0
+	while [ "$i" -lt 50 ]; do
+		c=$($TMUX list-clients -F x 2>/dev/null | grep -c x)
+		[ "$c" -eq "$1" ] && return 0
+		sleep 0.2
+		i=$((i + 1))
+	done
+	fail "expected $1 clients, have $c"
+}
+
+$TMUX new-session -d -s m -x 80 -y 24 'cat' || exit 1
+$TMUX split-window -t m:0 'cat' || exit 1
+p0=$($TMUX display-message -p -t m:0.0 '#{pane_id}')
+p1=$($TMUX display-message -p -t m:0.1 '#{pane_id}')
+$TMUX set -g display-panes-format 'P#{pane_index}' ||
+	fail "set display-panes-format failed"
+
+$TMUX2 new-session -d -s out -x 80 -y 24 "$TMUX attach -t m" || exit 1
+wait_clients 1
+
+capture()
+{
+	$TMUX2 capture-pane -p -t out:0 2>/dev/null
+}
+
+wait_capture()
+{
+	i=0
+	while [ "$i" -lt 50 ]; do
+		CAPTURED=$(capture)
+		printf '%s\n' "$CAPTURED" | grep -F -q "$1" && return 0
+		sleep 0.2
+		i=$((i + 1))
+	done
+	fail "timed out waiting for '$1' in capture"
+}
+
+# Entry, default zoom, and exit.
+$TMUX display-panes -d 0 -t "$p0" || fail "display-panes failed"
+wait_format "$p0" '#{pane_mode}' 'panes-mode'
+wait_format "$p0" '#{window_zoomed_flag}' '1'
+wait_capture 'P0'
+wait_capture 'P1'
+$TMUX send-keys -t "$p0" q || fail "exit panes mode failed"
+wait_format "$p0" '#{pane_in_mode}' '0'
+wait_format "$p0" '#{window_zoomed_flag}' '0'
+
+# -Z starts unzoomed.
+$TMUX display-panes -Zd 0 -t "$p0" || fail "display-panes -Z failed"
+wait_format "$p0" '#{pane_mode}' 'panes-mode'
+wait_format "$p0" '#{window_zoomed_flag}' '0'
+$TMUX send-keys -t "$p0" q || fail "exit unzoomed panes mode failed"
+wait_format "$p0" '#{pane_in_mode}' '0'
+
+# Selection keys run the command template and close the mode.
+$TMUX set -g @picked none || fail "set @picked failed"
+$TMUX display-panes -d 0 -t "$p0" 'set -g @picked %%' ||
+	fail "display-panes selection failed"
+wait_format "$p0" '#{pane_mode}' 'panes-mode'
+$TMUX send-keys -t "$p0" 1 || fail "select pane failed"
+wait_format "$p0" '#{pane_in_mode}' '0'
+wait_option @picked "$p1"
+
+# Commands after display-panes run immediately while the mode remains.
+$TMUX set -g @after none || fail "set @after failed"
+$TMUX display-panes -Nd 500 -t "$p0" \; set -g @after fast ||
+	fail "display-panes immediate command failed"
+wait_option @after fast
+wait_format "$p0" '#{pane_mode}' 'panes-mode'
+wait_format "$p0" '#{pane_in_mode}' '0'
+
+# Existing zoom is restored on exit.
+$TMUX select-pane -t "$p0" || fail "select p0 failed"
+$TMUX resize-pane -Z -t "$p0" || fail "zoom failed"
+wait_format "$p0" '#{window_zoomed_flag}' '1'
+$TMUX display-panes -d 0 -t "$p0" || fail "display-panes zoomed failed"
+wait_format "$p0" '#{pane_mode}' 'panes-mode'
+$TMUX send-keys -t "$p0" q || fail "exit zoomed panes mode failed"
+wait_format "$p0" '#{pane_in_mode}' '0'
+wait_format "$p0" '#{window_zoomed_flag}' '1'
+$TMUX resize-pane -Z -t "$p0" || fail "unzoom cleanup failed"
+
+# Panes mode can be stacked above another mode and returns to it on exit.
+$TMUX copy-mode -t "$p0" || fail "copy-mode failed"
+wait_format "$p0" '#{pane_mode}' 'copy-mode'
+$TMUX display-panes -d 0 -t "$p0" 'set -g @picked %%' ||
+	fail "display-panes over copy-mode failed"
+wait_format "$p0" '#{pane_mode}' 'panes-mode'
+$TMUX send-keys -t "$p0" 1 || fail "select from stacked mode failed"
+wait_format "$p0" '#{pane_mode}' 'copy-mode'
+wait_option @picked "$p1"
+$TMUX send-keys -t "$p0" -X cancel || fail "copy-mode cancel failed"
+wait_format "$p0" '#{pane_in_mode}' '0'
+
+# Panes mode is not kept underneath another mode.
+$TMUX display-panes -d 0 -t "$p0" || fail "display-panes no-stack failed"
+wait_format "$p0" '#{pane_mode}' 'panes-mode'
+$TMUX copy-mode -t "$p0" || fail "copy-mode over panes-mode failed"
+wait_format "$p0" '#{pane_mode}' 'copy-mode'
+$TMUX send-keys -t "$p0" -X cancel || fail "copy-mode cancel failed"
+wait_format "$p0" '#{pane_in_mode}' '0'
+wait_format "$p0" '#{window_zoomed_flag}' '0'
+
+# -s shows panes from a different source window but enters the mode in the
+# target pane.
+$TMUX new-window -d -t m: -n src 'cat' || fail "new source window failed"
+$TMUX split-window -t m:src 'cat' || fail "split source window failed"
+sp0=$($TMUX display-message -p -t m:src.0 '#{pane_id}')
+sp1=$($TMUX display-message -p -t m:src.1 '#{pane_id}')
+$TMUX respawn-pane -k -t "$sp0" 'printf "SOURCE-PANE\n"; exec cat' ||
+	fail "write source marker failed"
+$TMUX set -g display-panes-format '' || fail "clear source display format failed"
+$TMUX set -w -t m:src display-panes-format 'SOURCE-ONLY' ||
+	fail "set source window display format failed"
+$TMUX set -g @picked none || fail "reset @picked failed"
+$TMUX display-panes -d 0 -s m:src -t "$p0" 'set -g @picked %%' ||
+	fail "display-panes source window failed"
+wait_format "$p0" '#{pane_mode}' 'panes-mode'
+wait_capture 'SOURCE-PANE'
+CAPTURED=$(capture)
+printf '%s\n' "$CAPTURED" | grep -F -q 'SOURCE-ONLY' &&
+	fail "used source window display-panes-format"
+$TMUX send-keys -t "$p0" 1 || fail "select source pane failed"
+wait_format "$p0" '#{pane_in_mode}' '0'
+wait_option @picked "$sp1"
+$TMUX kill-window -t m:src || fail "kill source window failed"
+$TMUX set -g display-panes-format 'P#{pane_index}' ||
+	fail "reset display-panes-format after source failed"
+
+# pane-border-status rows are drawn as plain preview borders and do not shift
+# pane content into the status row.
+$TMUX set -w -t m:0 pane-border-status top ||
+	fail "set pane-border-status failed"
+$TMUX set -g display-panes-format '' || fail "clear display-panes-format failed"
+$TMUX respawn-pane -k -t "$p0" 'printf "STATUS-TOP\n"; exec cat' ||
+	fail "write status marker failed"
+wait_capture 'STATUS-TOP'
+$TMUX display-panes -d 0 -t "$p0" || fail "display-panes status failed"
+wait_format "$p0" '#{pane_mode}' 'panes-mode'
+wait_capture 'STATUS-TOP'
+CAPTURED=$(capture)
+first=$(printf '%s\n' "$CAPTURED" | sed -n '1p')
+second=$(printf '%s\n' "$CAPTURED" | sed -n '2p')
+printf '%s\n' "$first" | grep -F -q 'STATUS-TOP' &&
+	fail "pane content drawn in status border row"
+printf '%s\n' "$second" | grep -F -q 'STATUS-TOP' ||
+	fail "pane content not drawn below status border row"
+$TMUX send-keys -t "$p0" q || fail "exit status panes mode failed"
+wait_format "$p0" '#{pane_in_mode}' '0'
+$TMUX set -w -t m:0 pane-border-status off ||
+	fail "reset pane-border-status failed"
+$TMUX set -g display-panes-format 'P#{pane_index}' ||
+	fail "reset display-panes-format failed"
+
+# Floating panes are always framed in panes-mode, independent of their real
+# pane-border-lines setting.
+fp=$($TMUX new-pane -dPF '#{pane_id}' -B none -x 30 -y 8 -X 8 -Y 3 \
+    -t m:0 'cat') || fail "new borderless floating pane failed"
+$TMUX set -g display-panes-format '' || fail "clear display-panes-format failed"
+$TMUX display-panes -Zd 0 -t "$fp" || fail "display-panes floating failed"
+wait_format "$fp" '#{pane_mode}' 'panes-mode'
+wait_capture '┌'
+wait_capture '┘'
+$TMUX send-keys -t "$fp" q || fail "exit floating panes mode failed"
+wait_format "$fp" '#{pane_in_mode}' '0'
+
+$TMUX display-panes -d 0 -t "$fp" || fail "display-panes floating zoomed failed"
+wait_format "$fp" '#{pane_mode}' 'panes-mode'
+wait_format "$fp" '#{window_zoomed_flag}' '1'
+wait_capture '┌'
+wait_capture '┘'
+$TMUX send-keys -t "$fp" q || fail "exit zoomed floating panes mode failed"
+wait_format "$fp" '#{pane_in_mode}' '0'
+wait_format "$fp" '#{window_zoomed_flag}' '0'
+
+$TMUX resize-pane -t "$fp" -x 48 -y 14 ||
+	fail "resize floating pane larger failed"
+$TMUX set -g display-panes-format '#[align=right]FP#{pane_width}x#{pane_height}' ||
+	fail "set floating display-panes-format failed"
+$TMUX display-panes -Zd 0 -t "$fp" || fail "display-panes floating format failed"
+wait_format "$fp" '#{pane_mode}' 'panes-mode'
+wait_capture 'FP48x14'
+$TMUX resize-pane -t "$fp" -x 30 -y 10 ||
+	fail "resize floating pane smaller failed"
+wait_capture 'FP30x10'
+$TMUX send-keys -t "$fp" q || fail "exit floating format panes mode failed"
+wait_format "$fp" '#{pane_in_mode}' '0'
+
+$TMUX kill-pane -t "$fp" || fail "kill floating pane failed"
+$TMUX set -g display-panes-format 'P#{pane_index}' ||
+	fail "reset display-panes-format after floating failed"
+
+exit 0
diff --git a/regress/mode-kill.sh b/regress/mode-kill.sh
index a3e0d09b9..d9fb4dc64 100755
--- a/regress/mode-kill.sh
+++ b/regress/mode-kill.sh
@@ -8,9 +8,11 @@
 # - copy-mode -k (window-copy.c);
 # - choose-tree -k (window-tree.c);
 # - choose-buffer -k (window-buffer.c).
+# - display-panes -k (window-panes.c).
 #
 # choose-tree and choose-buffer share cmd_choose_tree_exec(), which also backs
-# choose-client and customize-mode, so those are not repeated.
+# choose-client, customize-mode, and display-panes, so choose-client and
+# customize-mode are not repeated.
 #
 # Each mode is entered in the active pane of a two-pane window: exiting with
 # -k must remove that pane and leave the other. copy-mode is left with the
@@ -147,7 +149,7 @@ wait_mode "$active" 0
 pane_gone "$active" && fail 'copy-mode: pane killed without -k'
 $TMUX kill-window -t m:w 2>/dev/null
 
-# --- choose-tree -k and choose-buffer -k kill the pane ----------------------
+# --- choose-tree -k, choose-buffer -k, and display-panes -k kill the pane ---
 #
 # These need the client to draw the mode before a key acts, so attach one now.
 # A paste buffer is needed for choose-buffer to have something to show, and a
@@ -168,4 +170,11 @@ wait_for 'BUFMARK'
 $TMUX send-keys -t m:w q || fail "choose-buffer exit failed"
 check_killed 'choose-buffer -k'
 
+open_window
+$TMUX set -g display-panes-format 'DPMARK' || fail "set display-panes-format"
+$TMUX display-panes -k -d 0 -t m:w || fail "display-panes -k failed"
+wait_for 'DPMARK'
+$TMUX send-keys -t m:w q || fail "display-panes exit failed"
+check_killed 'display-panes -k'
+
 exit 0