Various refactorings and cleanups

osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerLoungeSubScreen.cs

@@ -40,7 +40,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         [Test]
         public void TestJoinRoomWithoutPassword()
         {
-            addRoom(false);
+            AddStep("add room", () => RoomManager.AddRooms(1, withPassword: false));
             AddStep("select room", () => InputManager.Key(Key.Down));
             AddStep("join room", () => InputManager.Key(Key.Enter));
 
@@ -50,7 +50,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         [Test]
         public void TestPopoverHidesOnBackButton()
         {
-            addRoom(true);
+            AddStep("add room", () => RoomManager.AddRooms(1, withPassword: true));
             AddStep("select room", () => InputManager.Key(Key.Down));
             AddStep("attempt join room", () => InputManager.Key(Key.Enter));
 
@@ -70,7 +70,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         [Test]
         public void TestPopoverHidesOnLeavingScreen()
         {
-            addRoom(true);
+            AddStep("add room", () => RoomManager.AddRooms(1, withPassword: true));
             AddStep("select room", () => InputManager.Key(Key.Down));
             AddStep("attempt join room", () => InputManager.Key(Key.Enter));
 
@@ -86,7 +86,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             DrawableLoungeRoom.PasswordEntryPopover? passwordEntryPopover = null;
 
-            addRoom(true);
+            AddStep("add room", () => RoomManager.AddRooms(1, withPassword: true));
             AddStep("select room", () => InputManager.Key(Key.Down));
             AddStep("attempt join room", () => InputManager.Key(Key.Enter));
             AddUntilStep("password prompt appeared", () => (passwordEntryPopover = InputManager.ChildrenOfType<DrawableLoungeRoom.PasswordEntryPopover>().FirstOrDefault()) != null);
@@ -105,7 +105,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             DrawableLoungeRoom.PasswordEntryPopover? passwordEntryPopover = null;
 
-            addRoom(true);
+            AddStep("add room", () => RoomManager.AddRooms(1, withPassword: true));
             AddStep("select room", () => InputManager.Key(Key.Down));
             AddStep("attempt join room", () => InputManager.Key(Key.Enter));
             AddUntilStep("password prompt appeared", () => (passwordEntryPopover = InputManager.ChildrenOfType<DrawableLoungeRoom.PasswordEntryPopover>().FirstOrDefault()) != null);
@@ -124,7 +124,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             DrawableLoungeRoom.PasswordEntryPopover? passwordEntryPopover = null;
 
-            addRoom(true);
+            AddStep("add room", () => RoomManager.AddRooms(1, withPassword: true));
             AddStep("select room", () => InputManager.Key(Key.Down));
             AddStep("attempt join room", () => InputManager.Key(Key.Enter));
             AddUntilStep("password prompt appeared", () => (passwordEntryPopover = InputManager.ChildrenOfType<DrawableLoungeRoom.PasswordEntryPopover>().FirstOrDefault()) != null);
@@ -139,7 +139,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             DrawableLoungeRoom.PasswordEntryPopover? passwordEntryPopover = null;
 
-            addRoom(true);
+            AddStep("add room", () => RoomManager.AddRooms(1, withPassword: true));
             AddStep("select room", () => InputManager.Key(Key.Down));
             AddStep("attempt join room", () => InputManager.Key(Key.Enter));
             AddUntilStep("password prompt appeared", () => (passwordEntryPopover = InputManager.ChildrenOfType<DrawableLoungeRoom.PasswordEntryPopover>().FirstOrDefault()) != null);
@@ -149,20 +149,6 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddAssert("room joined", () => MultiplayerClient.RoomJoined);
         }
 
-        private void addRoom(bool withPassword)
-        {
-            int initialRoomCount = 0;
-
-            AddStep("add room", () =>
-            {
-                initialRoomCount = roomsContainer.Rooms.Count;
-                RoomManager.AddRooms(1, withPassword: withPassword);
-                loungeScreen.RefreshRooms();
-            });
-
-            AddUntilStep("wait for room to appear", () => roomsContainer.Rooms.Count == initialRoomCount + 1);
-        }
-
         protected override OnlinePlayTestSceneDependencies CreateOnlinePlayDependencies() => new MultiplayerTestSceneDependencies();
     }
 }

osu.Game.Tests/Visual/Playlists/TestScenePlaylistsLoungeSubScreen.cs

@@ -35,12 +35,7 @@ namespace osu.Game.Tests.Visual.Playlists
         [Test]
         public void TestManyRooms()
         {
-            AddStep("add rooms", () =>
-            {
-                RoomManager.AddRooms(500);
-                loungeScreen.RefreshRooms();
-            });
-
+            AddStep("add rooms", () => RoomManager.AddRooms(500));
             AddUntilStep("wait for rooms", () => roomsContainer.Rooms.Count == 500);
         }
 
@@ -49,12 +44,7 @@ namespace osu.Game.Tests.Visual.Playlists
         {
             AddStep("reset mouse", () => InputManager.ReleaseButton(MouseButton.Left));
 
-            AddStep("add rooms", () =>
-            {
-                RoomManager.AddRooms(30);
-                loungeScreen.RefreshRooms();
-            });
-
+            AddStep("add rooms", () => RoomManager.AddRooms(30));
             AddUntilStep("wait for rooms", () => roomsContainer.Rooms.Count == 30);
 
             AddUntilStep("first room is not masked", () => checkRoomVisible(roomsContainer.Rooms[0]));
@@ -71,12 +61,7 @@ namespace osu.Game.Tests.Visual.Playlists
         [Test]
         public void TestScrollSelectedIntoView()
         {
-            AddStep("add rooms", () =>
-            {
-                RoomManager.AddRooms(30);
-                loungeScreen.RefreshRooms();
-            });
-
+            AddStep("add rooms", () => RoomManager.AddRooms(30));
             AddUntilStep("wait for rooms", () => roomsContainer.Rooms.Count == 30);
 
             AddUntilStep("first room is not masked", () => checkRoomVisible(roomsContainer.Rooms[0]));
@@ -90,12 +75,7 @@ namespace osu.Game.Tests.Visual.Playlists
         [Test]
         public void TestEnteringRoomTakesLeaseOnSelection()
         {
-            AddStep("add rooms", () =>
-            {
-                RoomManager.AddRooms(1);
-                loungeScreen.RefreshRooms();
-            });
-
+            AddStep("add rooms", () => RoomManager.AddRooms(1));
             AddUntilStep("wait for rooms", () => roomsContainer.Rooms.Count == 1);
 
             AddAssert("selected room is not disabled", () => !loungeScreen.SelectedRoom.Disabled);

osu.Game/Online/Multiplayer/IMultiplayerLoungeServer.cs

@@ -10,6 +10,11 @@ namespace osu.Game.Online.Multiplayer
     /// </summary>
     public interface IMultiplayerLoungeServer
     {
+        /// <summary>
+        /// Request to create a multiplayer room.
+        /// </summary>
+        /// <param name="room">The room to create.</param>
+        /// <returns>The created multiplayer room.</returns>
         Task<MultiplayerRoom> CreateRoom(MultiplayerRoom room);
 
         /// <summary>

osu.Game/Online/Multiplayer/MultiplayerClient.cs

@@ -168,7 +168,7 @@ namespace osu.Game.Online.Multiplayer
         public async Task CreateRoom(Room room)
         {
             if (Room != null)
-                throw new InvalidOperationException("Cannot join a multiplayer room while already in one.");
+                throw new InvalidOperationException("Cannot create a multiplayer room while already in one.");
 
             var cancellationSource = joinCancellationSource = new CancellationTokenSource();
             await initRoom(room, r => CreateRoomInternal(new MultiplayerRoom(room)), cancellationSource.Token).ConfigureAwait(false);
@@ -212,6 +212,7 @@ namespace osu.Game.Online.Multiplayer
                     APIRoom.RoomID = joinedRoom.RoomID;
                     APIRoom.Playlist = joinedRoom.Playlist.Select(item => new PlaylistItem(item)).ToArray();
                     APIRoom.CurrentPlaylistItem = APIRoom.Playlist.Single(item => item.ID == joinedRoom.Settings.PlaylistItemId);
+                    // The server will null out the end date upon the host joining the room, but the null value is never communicated to the client.
                     APIRoom.EndDate = null;
 
                     Debug.Assert(LocalUser != null);

osu.Game/Online/Rooms/CreateRoomRequest.cs

@@ -15,6 +15,8 @@ namespace osu.Game.Online.Rooms
         public CreateRoomRequest(Room room)
         {
             Room = room;
+
+            // Also copy back to the source model, since it is likely to have been stored elsewhere.
             Success += r => Room.CopyFrom(r);
         }
 

osu.Game/Online/Rooms/JoinRoomRequest.cs

@@ -16,6 +16,8 @@ namespace osu.Game.Online.Rooms
         {
             Room = room;
             Password = password;
+
+            // Also copy back to the source model, since it is likely to have been stored elsewhere.
             Success += r => Room.CopyFrom(r);
         }
 

osu.Game/Screens/OnlinePlay/Lounge/DrawableLoungeRoom.cs

@@ -162,7 +162,7 @@ namespace osu.Game.Screens.OnlinePlay.Lounge
                 {
                     new OsuMenuItem("Create copy", MenuItemType.Standard, () =>
                     {
-                        lounge?.Clone(Room);
+                        lounge?.OpenCopy(Room);
                     })
                 };
 

osu.Game/Screens/OnlinePlay/Lounge/IOnlinePlayLounge.cs

@@ -18,10 +18,10 @@ namespace osu.Game.Screens.OnlinePlay.Lounge
         void Join(Room room, string? password, Action<Room>? onSuccess = null, Action<string>? onFailure = null);
 
         /// <summary>
-        /// Clones the given room and opens it as a fresh (not-yet-created) one.
+        /// Copies the given room and opens it as a fresh (not-yet-created) one.
         /// </summary>
-        /// <param name="room">The room to clone.</param>
-        void Clone(Room room);
+        /// <param name="room">The room to copy.</param>
+        void OpenCopy(Room room);
 
         /// <summary>
         /// Closes the given room.

osu.Game/Screens/OnlinePlay/Lounge/LoungeSubScreen.cs

@@ -309,7 +309,7 @@ namespace osu.Game.Screens.OnlinePlay.Lounge
 
             joiningRoomOperation = ongoingOperationTracker?.BeginOperation();
 
-            TryJoin(room, password, r =>
+            JoinInternal(room, password, r =>
             {
                 Open(room);
                 joiningRoomOperation?.Dispose();
@@ -323,9 +323,9 @@ namespace osu.Game.Screens.OnlinePlay.Lounge
             });
         });
 
-        protected abstract void TryJoin(Room room, string? password, Action<Room> onSuccess, Action<string> onFailure);
+        protected abstract void JoinInternal(Room room, string? password, Action<Room> onSuccess, Action<string> onFailure);
 
-        public void Clone(Room room)
+        public void OpenCopy(Room room)
         {
             Debug.Assert(room.RoomID != null);
 

osu.Game/Screens/OnlinePlay/Match/RoomSubScreen.cs

@@ -353,6 +353,9 @@ namespace osu.Game.Screens.OnlinePlay.Match
             return base.OnExiting(e);
         }
 
+        /// <summary>
+        /// Parts from the current room.
+        /// </summary>
         protected abstract void PartRoom();
 
         private bool ensureExitConfirmed()

osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerLoungeSubScreen.cs

@@ -81,7 +81,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
 
         protected override ListingPollingComponent CreatePollingComponent() => new MultiplayerListingPollingComponent();
 
-        protected override void TryJoin(Room room, string? password, Action<Room> onSuccess, Action<string> onFailure)
+        protected override void JoinInternal(Room room, string? password, Action<Room> onSuccess, Action<string> onFailure)
         {
             client.JoinRoom(room, password).ContinueWith(result =>
             {

osu.Game/Screens/OnlinePlay/Playlists/PlaylistsLoungeSubScreen.cs

@@ -60,7 +60,7 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
             return criteria;
         }
 
-        protected override void TryJoin(Room room, string? password, Action<Room> onSuccess, Action<string> onFailure)
+        protected override void JoinInternal(Room room, string? password, Action<Room> onSuccess, Action<string> onFailure)
         {
             var joinRoomRequest = new JoinRoomRequest(room, password);