server_disconnected emits on client when authentication is failed

[Summersay415]

Tested versions

• Reproducible in: v4.0.beta17.official [c400205], v4.1.4.stable.official [fe0e8e5], v4.2.2.stable.official [15073af], v4.3.rc2.official [3978628]

System information

Godot v4.3.rc2 - Ubuntu 24.04 LTS 24.04 - X11 - GLES3 (Compatibility) - Mesa Intel(R) Graphics (ADL GT2) - 12th Gen Intel(R) Core(TM) i5-1235U (12 Threads)

Issue description

server_disconnected signal emits on client when authenticating is failed, and I think this is not correct, because connected_to_server doesn't emit.

Steps to reproduce

1. Set authenticate callback which rejects clients with multiplayer.multiplayer_peer.disconnect_peer(<peer>) (if clients gets rejected with timeout, this also works).
2. On one game instance, create server.
3. On other game instance, try to connect.
4. Observe both peer_authentication_failed and server_disconnected emitted on client.

Minimal reproduction project (MRP)

mrp.zip

1. Run 2 instances.
2. On first, click "create".
3. On second, click "join".
4. Observe both peer_authentication_failed and server_disconnected emitted on client (visible in console).

[RedMser]

Maybe something like this would be enough? (Untested! Needs someone who's more familiar with the multiplayer code to have another look, and decide if this is considered a bug or not.)

diff --git a/modules/multiplayer/scene_multiplayer.cpp b/modules/multiplayer/scene_multiplayer.cpp
index 99aba680cc..0488d302e3 100644
--- a/modules/multiplayer/scene_multiplayer.cpp
+++ b/modules/multiplayer/scene_multiplayer.cpp
@@ -57,7 +57,7 @@ void SceneMultiplayer::_update_status() {
 		if (status == MultiplayerPeer::CONNECTION_DISCONNECTED) {
 			if (last_connection_status == MultiplayerPeer::CONNECTION_CONNECTING) {
 				emit_signal(SNAME("connection_failed"));
-			} else {
+			} else if (!pending_peers.has(get_unique_id())) {
 				emit_signal(SNAME("server_disconnected"));
 			}
 			clear();