Add the ability to switch to and use a beta stream

osu.Desktop/Updater/VelopackUpdateManager.cs

@@ -2,10 +2,13 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
+using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 using osu.Framework.Allocation;
+using osu.Framework.Bindables;
 using osu.Framework.Logging;
 using osu.Game;
+using osu.Game.Configuration;
 using osu.Game.Overlays;
 using osu.Game.Overlays.Notifications;
 using osu.Game.Screens.Play;
@@ -16,7 +19,7 @@ namespace osu.Desktop.Updater
 {
     public partial class VelopackUpdateManager : Game.Updater.UpdateManager
     {
-        private readonly UpdateManager updateManager;
+        private UpdateManager updateManager = null!;
         private INotificationOverlay notificationOverlay = null!;
 
         [Resolved]
@@ -25,22 +28,45 @@ public partial class VelopackUpdateManager : Game.Updater.UpdateManager
         [Resolved]
         private ILocalUserPlayInfo? localUserInfo { get; set; }
 
+        [Resolved]
+        private OsuConfigManager osuConfigManager { get; set; } = null!;
+
         private bool isInGameplay => localUserInfo?.PlayingState.Value != LocalUserPlayingState.NotPlaying;
 
         private UpdateInfo? pendingUpdate;
 
-        public VelopackUpdateManager()
-        {
-            updateManager = new UpdateManager(new GithubSource(@"https://github.com/ppy/osu", null, false), new UpdateOptions
-            {
-                AllowVersionDowngrade = true,
-            });
-        }
+        private Bindable<ReleaseStream> releaseStream => osuConfigManager.GetBindable<ReleaseStream>(OsuSetting.ReleaseStream);
 
         [BackgroundDependencyLoader]
         private void load(INotificationOverlay notifications)
         {
             notificationOverlay = notifications;
+
+            UpdateOptions options = new UpdateOptions
+            {
+                AllowVersionDowngrade = true,
+            };
+
+            string arch = RuntimeInformation.OSArchitecture.ToString().ToLowerInvariant();
+
+            string platform = Environment.OSVersion.Platform switch
+            {
+                PlatformID.Win32NT => "win",
+                PlatformID.Unix => "linux-" + arch,
+                PlatformID.MacOSX => "osx-" + arch,
+                _ => throw new PlatformNotSupportedException(),
+            };
+
+            if (releaseStream.Value == ReleaseStream.Photon)
+            {
+                options.ExplicitChannel = $"{platform}-photon";
+                // TODO: The logging here is not correct. It should be reading from `VelopackLocator.GetDefault(null).Channel` instead. Should also probably be moved to a more appropriate location.
+                Logger.Log("Using photon channel");
+            }
+            else if (releaseStream.Value == ReleaseStream.Lazer)
+                options.ExplicitChannel = platform;
+
+            updateManager = new UpdateManager(new GithubSource(@"https://github.com/ppy/osu", null, false), options);
         }
 
         protected override async Task<bool> PerformUpdateCheck() => await checkForUpdateAsync().ConfigureAwait(false);

osu.Game/Configuration/ReleaseStream.cs

@@ -6,6 +6,7 @@ namespace osu.Game.Configuration
     public enum ReleaseStream
     {
         Lazer,
+        Photon,
         //Stable40,
         //Beta40,
         //Stable

osu.Game/Overlays/Settings/Sections/General/UpdateSettings.cs

@@ -13,6 +13,7 @@
 using osu.Framework.Statistics;
 using osu.Game.Configuration;
 using osu.Game.Localisation;
+using osu.Game.Overlays.Dialog;
 using osu.Game.Overlays.Notifications;
 using osu.Game.Overlays.Settings.Sections.Maintenance;
 using osu.Game.Updater;
@@ -36,13 +37,40 @@ public partial class UpdateSettings : SettingsSubsection
         [Resolved]
         private Storage storage { get; set; } = null!;
 
+        [Resolved]
+        private IDialogOverlay dialogOverlay { get; set; } = null!;
+
         [BackgroundDependencyLoader]
         private void load(OsuConfigManager config, OsuGame? game)
         {
+            var releaseStream = config.GetBindable<ReleaseStream>(OsuSetting.ReleaseStream);
             Add(new SettingsEnumDropdown<ReleaseStream>
             {
                 LabelText = GeneralSettingsStrings.ReleaseStream,
-                Current = config.GetBindable<ReleaseStream>(OsuSetting.ReleaseStream),
+                Current = releaseStream,
+            });
+
+            bool debounce = false;
+            releaseStream.BindValueChanged(r =>
+            {
+                if (debounce)
+                {
+                    debounce = false;
+                    return;
+                }
+
+                if (game?.RestartAppWhenExited() == true)
+                {
+                    game.AttemptExit();
+                }
+                else
+                {
+                    dialogOverlay.Push(new ConfirmDialog("You must restart after changing release streams. Are you sure about this?", () => game?.AttemptExit(), () =>
+                    {
+                        debounce = true;
+                        releaseStream.Value = r.OldValue;
+                    }));
+                }
             });
 
             if (updateManager?.CanCheckForUpdate == true)