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

[mxnemu]

The default behaviour for X11 is to crash even on non-fatal errors when there is no error handler set. This change allows the window to stay open and may enable users to save their work when things go wrong.

This acts as a workaround for #65425 and #68471

[mxnemu]

clang-format makes the multiline string unreadable. Any advice on that?

[Riteo]

@mxnemu the rest of the code uses vformat's variadic arguments to workaround this issue:

OS::get_singleton()->alert(
		vformat("Your video card drivers seem not to support the required Vulkan version.\n\n"
				"If possible, consider updating your video card drivers or using the OpenGL 3 driver.\n\n"
				"You can enable the OpenGL 3 driver by starting the engine from the\n"
				"command line with the command:\n\n    \"%s\" --rendering-driver opengl3\n\n"
				"If you recently updated your video card drivers, try rebooting.",
				executable_name),
		"Unable to initialize Vulkan video driver");

vformat returns a String and ERR_PRINT should support it, as its internal method (_err_print_error) has lots of overloads for both Strings and char *, so this should work fine.

Edit: just noticed that those aren't variadic arguments lol. Glad to have put the example as otherwise I would have messed up things further.

[Riteo]

I haven't tested this but it looks fine!

[mxnemu]

Since the bugs aren't super easy to reproduce without installing a new window manager and configuring smart-borders, here are screenshots of my tests on Ubuntu 22.04 xmonad 0.15.

This branch - The godot window stays open and usable when an error occures:

This branch - Using xkill still ends godot, just the same as in the official release. So no unintended effects here.

Godot 4.0 before the patch - the window crashes on focus change as described in the issue reports:

[mxnemu]

Can this get merged now, so it will be in the next dev-snapshot and people can report anything unexpected?

[bruvzg]

Suggested change

	String(message), error->request_code, error->minor_code, error->serial));
	String::utf8(message), error->request_code, error->minor_code, error->serial));

According to docs: "The returned text is in the encoding of the current locale.", so it's likely UTF-8 in most cases, String(x) is for ASCII only.

[akien-mga]

@mxnemu Are you able to do this change? This seems to be the only step left before merging.

[mxnemu]

Yes, I just tested it locally and amended my commit. 👍

Sorry for my delay and thanks for the help everyone.

[akien-mga]

For the record, your commit seems not to be linked to your GitHub account. See: Why are my commits linked to the wrong user? for more info.

[akien-mga]

Thanks! And congrats for your first merged Godot contribution 🎉