Merge pull request #75099 from mxnemu/add-default-x11-error-handler

[Linux/X11] Add a default error handler for X11 to avoid crashes.

platform/linuxbsd/x11/display_server_x11.cpp

@@ -855,12 +855,30 @@ Size2i DisplayServerX11::screen_get_size(int p_screen) const {
 	return _screen_get_rect(p_screen).size;
 }
 
+// A Handler to avoid crashing on non-fatal X errors by default.
+//
+// The original X11 error formatter `_XPrintDefaultError` is defined here:
+// https://gitlab.freedesktop.org/xorg/lib/libx11/-/blob/e45ca7b41dcd3ace7681d6897505f85d374640f2/src/XlibInt.c#L1322
+// It is not exposed through the API, accesses X11 internals,
+// and is much more complex, so this is a less complete simplified error X11 printer.
+int default_window_error_handler(Display *display, XErrorEvent *error) {
+	static char message[1024];
+	XGetErrorText(display, error->error_code, message, sizeof(message));
+
+	ERR_PRINT(vformat("Unhandled XServer error: %s"
+					  "\n   Major opcode of failed request: %d"
+					  "\n   Serial number of failed request: %d"
+					  "\n   Current serial number in output stream: %d",
+			String::utf8(message), error->request_code, error->minor_code, error->serial));
+	return 0;
+}
+
 bool g_bad_window = false;
 int bad_window_error_handler(Display *display, XErrorEvent *error) {
 	if (error->error_code == BadWindow) {
 		g_bad_window = true;
 	} else {
-		ERR_PRINT("Unhandled XServer error code: " + itos(error->error_code));
+		return default_window_error_handler(display, error);
 	}
 	return 0;
 }
@@ -5930,6 +5948,7 @@ DisplayServerX11::DisplayServerX11(const String &p_rendering_driver, WindowMode
 
 	portal_desktop = memnew(FreeDesktopPortalDesktop);
 #endif
+	XSetErrorHandler(&default_window_error_handler);
 
 	r_error = OK;
 }