From cf110d9d1de2046372e18d5eac8447bf7fbb251c Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicholas.marriott@gmail.com>
Date: Tue, 14 Jul 2026 10:07:51 +0100
Subject: [PATCH] Copy mode redraw test.

---
 regress/copy-mode-redraw.sh | 125 ++++++++++++++++++++++++++++++++++++
 1 file changed, 125 insertions(+)
 create mode 100644 regress/copy-mode-redraw.sh

diff --git a/regress/copy-mode-redraw.sh b/regress/copy-mode-redraw.sh
new file mode 100644
index 000000000..541f38afb
--- /dev/null
+++ b/regress/copy-mode-redraw.sh
@@ -0,0 +1,125 @@
+#!/bin/sh
+
+# Exercise copy mode redraw through a real client. An inner tmux is attached
+# inside an outer tmux pane; the outer pane is captured to inspect what the
+# inner client actually drew.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+TMUX="$TEST_TMUX -LtestA$$ -f/dev/null"
+TMUX2="$TEST_TMUX -LtestB$$ -f/dev/null"
+
+fail() {
+	echo "$*" >&2
+	exit 1
+}
+
+capture() {
+	$TMUX capturep -pS0 -E- >$TMP || exit 1
+}
+
+check_line() {
+	line=$1
+	want=$2
+	got=$(sed -n "$line"p $TMP)
+	[ "$got" = "$want" ] || fail "line $line: expected '$want', got '$got'"
+}
+
+check_grep() {
+	pattern=$1
+	grep -Fq "$pattern" $TMP || fail "missing pattern: $pattern"
+}
+
+check_no_grep() {
+	pattern=$1
+	grep -Fq "$pattern" $TMP && fail "unexpected pattern: $pattern"
+}
+
+redraw() {
+	$TMUX2 send -X cursor-right || exit 1
+	sleep 1
+	capture
+}
+
+$TMUX kill-server 2>/dev/null
+$TMUX2 kill-server 2>/dev/null
+
+TMP=$(mktemp)
+trap "rm -f $TMP; $TMUX kill-server 2>/dev/null; $TMUX2 kill-server 2>/dev/null" 0 1 15
+
+$TMUX2 -f/dev/null new -d -x48 -y8 -s test \
+	"awk 'BEGIN { for (i = 0; i < 90; i++) { if (i % 2 == 0) printf \"L%03d-ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-END\\n\", i; else printf \"S%03d\\n\", i } }'; exec sleep 100" || exit 1
+$TMUX2 set -g status off || exit 1
+$TMUX2 set -g mode-keys vi || exit 1
+$TMUX2 set -g copy-mode-line-numbers off || exit 1
+$TMUX2 set -g copy-mode-position-format "#[align=right][23/100-LONGTAIL]" || exit 1
+
+$TMUX -f/dev/null new -d -x48 -y8 || exit 1
+$TMUX set -g status off || exit 1
+$TMUX send -l "$TMUX2 attach" || exit 1
+$TMUX send Enter || exit 1
+sleep 1
+
+CLIENT=$($TMUX2 list-clients -F '#{client_name}' | head -1)
+[ -n "$CLIENT" ] || fail "no inner client"
+
+$TMUX2 copy-mode || exit 1
+$TMUX2 send -X history-top || exit 1
+sleep 1
+
+# Shrinking and moving the position indicator should not leave stale text from
+# the previous indicator, for different widths and alignments.
+for size in 20 48; do
+	$TMUX resizew -x$size -y8 || exit 1
+	$TMUX2 refresh -t"$CLIENT" -c || exit 1
+	sleep 1
+	for align in left centre right; do
+		$TMUX2 set -g copy-mode-position-format "#[align=$align][23/100-LONGTAIL]" || exit 1
+		redraw
+		check_grep "[23/100-LONGTAIL]"
+
+		$TMUX2 set -g copy-mode-position-format "#[align=$align][1/100]" || exit 1
+		redraw
+		check_grep "[1/100]"
+		check_no_grep "LONGTAIL"
+		check_no_grep "[1/100]]"
+	done
+
+	$TMUX2 set -g copy-mode-position-format "#[align=right][1/100]" || exit 1
+	redraw
+	$TMUX2 set -g copy-mode-position-format "#[align=right][23/100]" || exit 1
+	redraw
+	check_grep "[23/100]"
+done
+
+# Scrolling from long pane content to short pane content should clear the
+# remainder of the old line without relying on a full pre-clear.
+$TMUX resizew -x48 -y8 || exit 1
+$TMUX2 refresh -t"$CLIENT" -c || exit 1
+$TMUX2 send -X cancel || exit 1
+$TMUX2 copy-mode -H || exit 1
+$TMUX2 send -X history-top || exit 1
+sleep 1
+capture
+check_line 1 "L000-ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-END"
+
+$TMUX2 send -X scroll-down || exit 1
+sleep 1
+capture
+check_line 1 "S001"
+
+$TMUX2 send -X scroll-down || exit 1
+sleep 1
+capture
+check_line 1 "L002-ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-END"
+
+$TMUX2 send -X scroll-down || exit 1
+sleep 1
+capture
+check_line 1 "S003"
+
+exit 0