library_sockfs.js can access properties of undefined dest (logic flaw)

[adamscott]

Note

This issue was unearthed by us due to what seems an issue on our side. My colleague @Faless explains it on the Godot Dev Chat. Though, the issue underlined is still a logic flaw.

Regression introduced by #22630

emscripten/src/library_sockfs.js

Lines 632 to 647 in 06cebfc

	// if we don't have a cached connectionless UDP datagram connection, or
	// the TCP socket is still connecting, queue the message to be sent upon
	// connect, and lie, saying the data was sent now.
	if (!dest || dest.socket.readyState !== dest.socket.OPEN) {
	// if we're not connected, open a new connection
	if (sock.type === {{{ cDefs.SOCK_DGRAM }}}) {
	if (!dest || dest.socket.readyState === dest.socket.CLOSING || dest.socket.readyState === dest.socket.CLOSED) {
	dest = SOCKFS.websocket_sock_ops.createPeer(sock, addr, port);
	}
	}
	#if SOCKET_DEBUG
	dbg(`websocket: queuing (${length} bytes): ${new Uint8Array(data)}`);
	#endif
	dest.msg_send_queue.push(data);
	return length;
	}

If dest == null and sock.type !== {{{ cDefs.SOCK_DGRAM }}} (see code above), then the following error occurs: