fix: unlink wayland socket manually instead of calling wl_display_destroy (wlroots 0.19 multi-backend aborts on display destroy during shutdown)

src/backend/wayland/wl_backend.c

@@ -879,17 +879,21 @@ wl_display_close(void)
         wl_state.cursor = NULL;
     }
 
-    /* Tear down the Wayland display so the compositor socket is removed.
-     * Without this, restart (execvp) fails because the new instance finds
-     * a stale socket at $XDG_RUNTIME_DIR/wayland-N and refuses to start.
-     *
-     * The XWayland server was SIGKILL'd above and server->client was
-     * NULL'd to prevent wlr_xwayland_server_destroy from double-freeing
-     * the wl_client during display destroy signal dispatch.
-     *
-     * All remaining listeners were removed in the WL_LISTENER_REMOVE block
-     * above, so no dangling signal handlers remain. */
-    wl_display_destroy(wl_state.display);
+    /* Clean up the Wayland socket so a new compositor instance can bind.
+     * wl_display_destroy() would do this, but in wlroots 0.19 it aborts
+     * because the multi-backend's display-destroy handler iterates freed
+     * child backend pointers.  Since execvp replaces the entire process
+     * image, all memory and fd resources are reclaimed by the kernel.
+     * The socket file on disk is the only persistent resource we need
+     * to remove ourselves. */
+    if (wl_state.socket_name[0]) {
+        const char *rt = getenv("XDG_RUNTIME_DIR");
+        if (rt) {
+            char path[256];
+            snprintf(path, sizeof(path), "%s/%s", rt, wl_state.socket_name);
+            unlink(path);
+        }
+    }
     unsetenv("WAYLAND_DISPLAY");
     wl_state.renderer       = NULL;
     wl_state.backend        = NULL;