From 998417a7b0c04c84877b451d7d9b66ae193c3541 Mon Sep 17 00:00:00 2001
From: Ferdinand Bachmann <ferdinand.bachmann@yrlf.at>
Date: Thu, 12 Feb 2026 11:27:01 +0100
Subject: [PATCH] sway/main: fail if only one of --socket and --wayland-fd are
 given

---
 sway/main.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/sway/main.c b/sway/main.c
index 09688e115..e05c61430 100644
--- a/sway/main.c
+++ b/sway/main.c
@@ -1,3 +1,4 @@
+#include <fcntl.h>
 #include <getopt.h>
 #include <pango/pangocairo.h>
 #include <pthread.h>
@@ -305,6 +306,14 @@ int main(int argc, char **argv) {
 		allow_unsupported_gpu = parse_boolean(unsupported_gpu_env, false);
 	}
 
+	// Fail if only one of --socket and --wayland-fd are given.
+	if ((socket_name == NULL) ^ (socket_fd == -1)) {
+		fprintf(stderr,
+				"Both --socket and --wayland-fd are required for Wayland "
+				"socket handover, but only one was provided. Aborting.\n");
+		exit(EXIT_FAILURE);
+	}
+
 	// As the 'callback' function for wlr_log is equivalent to that for
 	// sway, we do not need to override it.
 	if (debug) {