From 4be32b232c189d9abee37405810e0e1e3438c0e3 Mon Sep 17 00:00:00 2001
From: Askaholic <askaholic@protonmail.com>
Date: Fri, 14 Mar 2025 15:27:12 -0400
Subject: [PATCH] Ignore duplicate 'Idle' and 'Lobby' messages

These are likely caused by a bug in the client launching multiple FA
instances. In this case we just ignore the extra messages and assume
that the player will close one of the FA processes shortly after launch.
---
 server/gameconnection.py                | 14 +++++++++
 tests/integration_tests/test_game.py    | 42 +++++++++++++++++++++++++
 tests/unit_tests/test_gameconnection.py | 21 +++++++++++--
 3 files changed, 74 insertions(+), 3 deletions(-)

diff --git a/server/gameconnection.py b/server/gameconnection.py
index 2f3d9f6b1..73774be53 100644
--- a/server/gameconnection.py
+++ b/server/gameconnection.py
@@ -114,6 +114,13 @@ async def _handle_idle_state(self):
         """
         assert self.game
 
+        if self.state is not GameConnectionState.INITIALIZING:
+            self._logger.warning(
+                "Ignoring unexpected 'Idle' state when state was %s",
+                self.state,
+            )
+            return
+
         if self.player == self.game.host:
             self.game.state = GameState.LOBBY
             self._state = GameConnectionState.CONNECTED_TO_HOST
@@ -132,6 +139,13 @@ async def _handle_lobby_state(self):
         """
         player_state = self.player.state
         if player_state == PlayerState.HOSTING:
+            if self.game.hosted_at is not None:
+                self._logger.warning(
+                    "Ignoring unexpected 'Lobby' state sent when the game was "
+                    "already hosted.",
+                )
+                return
+
             await self.send_HostGame(self.game.map.folder_name)
             self.game.set_hosted()
         # If the player is joining, we connect him to host
diff --git a/tests/integration_tests/test_game.py b/tests/integration_tests/test_game.py
index 3c90ecb45..62dfb51e7 100644
--- a/tests/integration_tests/test_game.py
+++ b/tests/integration_tests/test_game.py
@@ -1320,6 +1320,48 @@ async def test_ladder_game_not_joinable(lobby_server):
     }
 
 
+@fast_forward(60)
+async def test_gamestate_lobby_double_game_instance(lobby_server):
+    """There was a bug in the client that was causing multiple game instances
+    to launch simultaneously. This could cause the GpgNet messages in the game
+    startup sequence to be sent twice.
+    """
+    _, _, host_proto = await connect_and_sign_in(
+        ("test", "test_password"), lobby_server
+    )
+    _, _, guest_proto = await connect_and_sign_in(
+        ("Rhiza", "puff_the_magic_dragon"), lobby_server
+    )
+    await read_until_command(host_proto, "game_info")
+    await read_until_command(guest_proto, "game_info")
+
+    await host_proto.send_message({
+        "command": "game_host",
+        "mod": "faf",
+        "visibility": "public",
+    })
+    msg = await read_until_command(host_proto, "game_launch")
+    game_id = int(msg["uid"])
+
+    for _ in range(2):
+        await host_proto.send_message({
+            "target": "game",
+            "command": "GameState",
+            "args": ["Idle"]
+        })
+
+    for _ in range(2):
+        await host_proto.send_message({
+            "target": "game",
+            "command": "GameState",
+            "args": ["Lobby"]
+        })
+
+    await read_until_command(host_proto, "HostGame", target="game")
+
+    await join_game(guest_proto, game_id)
+
+
 @pytest.mark.flaky
 @fast_forward(60)
 async def test_gamestate_ended_clears_references(
diff --git a/tests/unit_tests/test_gameconnection.py b/tests/unit_tests/test_gameconnection.py
index f39b9facb..06821e838 100644
--- a/tests/unit_tests/test_gameconnection.py
+++ b/tests/unit_tests/test_gameconnection.py
@@ -99,18 +99,33 @@ async def test_connect_to_peer_disconnected(game_connection):
     await game_connection.connect_to_peer(peer)
 
 
-async def test_handle_action_GameState_idle_adds_connection(
+async def test_handle_action_GameState_idle_hosting(
     game: Game,
     game_connection: GameConnection,
     players
 ):
-    players.joining.game = game
     game_connection.player = players.hosting
     game_connection.game = game
 
     await game_connection.handle_action("GameState", ["Idle"])
 
-    game.add_game_connection.assert_called_with(game_connection)
+    game.add_game_connection.assert_called_once_with(game_connection)
+
+
+async def test_handle_action_GameState_idle_joining(
+    game: Game,
+    game_connection: GameConnection,
+    players
+):
+    game_connection.player = players.joining
+    game_connection.game = game
+
+    await game_connection.handle_action("GameState", ["Idle"])
+
+    assert players.joining.state == PlayerState.JOINING
+    assert game_connection.state == GameConnectionState.INITIALIZED
+
+    game.add_game_connection.assert_not_called()
 
 
 async def test_handle_action_GameState_idle_sets_player_state(