From fc9270c9430c18c4e114580c1005e1ae878cc9ec Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicholas.marriott@gmail.com>
Date: Mon, 3 Aug 2026 11:09:04 +0100
Subject: [PATCH] Test for socket error from Rayan Salhab.

---
 regress/server-socket-error.sh | 49 ++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100755 regress/server-socket-error.sh

diff --git a/regress/server-socket-error.sh b/regress/server-socket-error.sh
new file mode 100755
index 000000000..60ff4c07d
--- /dev/null
+++ b/regress/server-socket-error.sh
@@ -0,0 +1,49 @@
+#!/bin/sh
+
+# Server socket creation failures must produce a nonzero client exit status.
+
+PATH=/bin:/usr/bin
+TERM=screen
+export TERM
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+
+# Root bypasses directory mode bits, so it cannot trigger this failure.
+[ "$(id -u)" -eq 0 ] && exit 0
+
+TMP=$(mktemp -d) || exit 1
+SOCKET="$TMP/ro/socket"
+
+cleanup()
+{
+	chmod 700 "$TMP/ro" 2>/dev/null
+	rm -rf "$TMP"
+}
+
+fail()
+{
+	echo "$1" >&2
+	cleanup
+	exit 1
+}
+
+mkdir "$TMP/ro" || exit 1
+chmod 500 "$TMP/ro" || exit 1
+trap cleanup 0 1 15
+
+check_failure()
+{
+	output=$($TEST_TMUX -S "$SOCKET" -f/dev/null "$@" 2>&1)
+	retval=$?
+
+	[ "$retval" -ne 0 ] || fail "tmux $* exited zero: $output"
+	case "$output" in
+	"error creating $SOCKET ("*) ;;
+	*) fail "tmux $* produced unexpected error: $output" ;;
+	esac
+}
+
+check_failure start-server
+check_failure new-session -d
+
+exit 0