Make IPC port configurable via HostOptions

[tsunyoku]

Resolves #6127

Breaking changes

HostOptions.BindIPC has been superseded by HostOptions.IPCPort

Previously, the IPC port used for multiple instances of a single osu!framework app was hardcoded in the IPC host itself, effectively making it so that all osu!framework apps would share the same IPC port, which obviously cannot work.

To allow multiple osu!framework apps to utilise IPC concurrently, BindIPC has thus been replaced by IPCPort.

• Setting IPCPort = null is equivalent to BindIPC = false.
• Setting IPCPort to a non-null value is equivalent to BindIPC = true and will force the use the specific port provided.

Note that it is advised to use a "user port" (in the range of 1024-49151) as per RFC 6335.

[bdach]

Baseline changes to apply game-side after this:

diff --git a/Templates/Rulesets/ruleset-empty/osu.Game.Rulesets.EmptyFreeform.Tests/VisualTestRunner.cs b/Templates/Rulesets/ruleset-empty/osu.Game.Rulesets.EmptyFreeform.Tests/VisualTestRunner.cs
index 03ee7c9204..8b7a3e6045 100644
--- a/Templates/Rulesets/ruleset-empty/osu.Game.Rulesets.EmptyFreeform.Tests/VisualTestRunner.cs
+++ b/Templates/Rulesets/ruleset-empty/osu.Game.Rulesets.EmptyFreeform.Tests/VisualTestRunner.cs
@@ -13,7 +13,7 @@ public static class VisualTestRunner
         [STAThread]
         public static int Main(string[] args)
         {
-            using (DesktopGameHost host = Host.GetSuitableDesktopHost(@"osu", new HostOptions { BindIPC = true }))
+            using (DesktopGameHost host = Host.GetSuitableDesktopHost(@"osu", new HostOptions { IPCPort = 45356 }))
             {
                 host.Run(new OsuTestBrowser());
                 return 0;
diff --git a/Templates/Rulesets/ruleset-example/osu.Game.Rulesets.Pippidon.Tests/VisualTestRunner.cs b/Templates/Rulesets/ruleset-example/osu.Game.Rulesets.Pippidon.Tests/VisualTestRunner.cs
index 55c0cf6a3b..8a270bf5f0 100644
--- a/Templates/Rulesets/ruleset-example/osu.Game.Rulesets.Pippidon.Tests/VisualTestRunner.cs
+++ b/Templates/Rulesets/ruleset-example/osu.Game.Rulesets.Pippidon.Tests/VisualTestRunner.cs
@@ -13,7 +13,7 @@ public static class VisualTestRunner
         [STAThread]
         public static int Main(string[] args)
         {
-            using (DesktopGameHost host = Host.GetSuitableDesktopHost(@"osu", new HostOptions { BindIPC = true }))
+            using (DesktopGameHost host = Host.GetSuitableDesktopHost(@"osu", new HostOptions { IPCPort = 45356 }))
             {
                 host.Run(new OsuTestBrowser());
                 return 0;
diff --git a/Templates/Rulesets/ruleset-scrolling-empty/osu.Game.Rulesets.EmptyScrolling.Tests/VisualTestRunner.cs b/Templates/Rulesets/ruleset-scrolling-empty/osu.Game.Rulesets.EmptyScrolling.Tests/VisualTestRunner.cs
index b45505678c..f2fafee414 100644
--- a/Templates/Rulesets/ruleset-scrolling-empty/osu.Game.Rulesets.EmptyScrolling.Tests/VisualTestRunner.cs
+++ b/Templates/Rulesets/ruleset-scrolling-empty/osu.Game.Rulesets.EmptyScrolling.Tests/VisualTestRunner.cs
@@ -13,7 +13,7 @@ public static class VisualTestRunner
         [STAThread]
         public static int Main(string[] args)
         {
-            using (DesktopGameHost host = Host.GetSuitableDesktopHost(@"osu", new HostOptions { BindIPC = true }))
+            using (DesktopGameHost host = Host.GetSuitableDesktopHost(@"osu", new HostOptions { IPCPort = 45356 }))
             {
                 host.Run(new OsuTestBrowser());
                 return 0;
diff --git a/Templates/Rulesets/ruleset-scrolling-example/osu.Game.Rulesets.Pippidon.Tests/VisualTestRunner.cs b/Templates/Rulesets/ruleset-scrolling-example/osu.Game.Rulesets.Pippidon.Tests/VisualTestRunner.cs
index 55c0cf6a3b..8a270bf5f0 100644
--- a/Templates/Rulesets/ruleset-scrolling-example/osu.Game.Rulesets.Pippidon.Tests/VisualTestRunner.cs
+++ b/Templates/Rulesets/ruleset-scrolling-example/osu.Game.Rulesets.Pippidon.Tests/VisualTestRunner.cs
@@ -13,7 +13,7 @@ public static class VisualTestRunner
         [STAThread]
         public static int Main(string[] args)
         {
-            using (DesktopGameHost host = Host.GetSuitableDesktopHost(@"osu", new HostOptions { BindIPC = true }))
+            using (DesktopGameHost host = Host.GetSuitableDesktopHost(@"osu", new HostOptions { IPCPort = 45356 }))
             {
                 host.Run(new OsuTestBrowser());
                 return 0;
diff --git a/osu.Desktop/Program.cs b/osu.Desktop/Program.cs
index 6b95a82703..ef3aff6bdf 100644
--- a/osu.Desktop/Program.cs
+++ b/osu.Desktop/Program.cs
@@ -102,7 +102,7 @@ public static void Main(string[] args)
                 }
             }
 
-            using (DesktopGameHost host = Host.GetSuitableDesktopHost(gameName, new HostOptions { BindIPC = !tournamentClient }))
+            using (DesktopGameHost host = Host.GetSuitableDesktopHost(gameName, new HostOptions { IPCPort = tournamentClient ? null : 45356 }))
             {
                 if (!host.IsPrimaryInstance)
                 {
diff --git a/osu.Game.Tests/Visual/Navigation/TestSceneInterProcessCommunication.cs b/osu.Game.Tests/Visual/Navigation/TestSceneInterProcessCommunication.cs
index 1ecd38e1d3..85531b66a2 100644
--- a/osu.Game.Tests/Visual/Navigation/TestSceneInterProcessCommunication.cs
+++ b/osu.Game.Tests/Visual/Navigation/TestSceneInterProcessCommunication.cs
@@ -63,7 +63,7 @@ public override void SetUpSteps()
             });
             AddStep("create IPC sender channels", () =>
             {
-                ipcSenderHost = new HeadlessGameHost(gameHost.Name, new HostOptions { BindIPC = true });
+                ipcSenderHost = new HeadlessGameHost(gameHost.Name, new HostOptions { IPCPort = 45356 });
                 osuSchemeLinkIPCSender = new OsuSchemeLinkIPCChannel(ipcSenderHost);
                 archiveImportIPCSender = new ArchiveImportIPCChannel(ipcSenderHost);
             });
diff --git a/osu.Game.Tournament.Tests/TournamentTestRunner.cs b/osu.Game.Tournament.Tests/TournamentTestRunner.cs
index 5f642b14f5..1d38648243 100644
--- a/osu.Game.Tournament.Tests/TournamentTestRunner.cs
+++ b/osu.Game.Tournament.Tests/TournamentTestRunner.cs
@@ -12,7 +12,7 @@ public static class TournamentTestRunner
         [STAThread]
         public static int Main(string[] args)
         {
-            using (DesktopGameHost host = Host.GetSuitableDesktopHost(@"osu-development", new HostOptions { BindIPC = true }))
+            using (DesktopGameHost host = Host.GetSuitableDesktopHost(@"osu-development", new HostOptions { IPCPort = 45356 }))
             {
                 host.Run(new TournamentTestBrowser());
                 return 0;
diff --git a/osu.Game/Tests/CleanRunHeadlessGameHost.cs b/osu.Game/Tests/CleanRunHeadlessGameHost.cs
index f3c69201e2..6a5c756a9e 100644
--- a/osu.Game/Tests/CleanRunHeadlessGameHost.cs
+++ b/osu.Game/Tests/CleanRunHeadlessGameHost.cs
@@ -27,7 +27,7 @@ public class CleanRunHeadlessGameHost : TestRunHeadlessGameHost
                                         [CallerMemberName] string callingMethodName = @"")
             : base($"{callingMethodName}-{Guid.NewGuid()}", new HostOptions
             {
-                BindIPC = bindIPC,
+                IPCPort = 45356,
             }, bypassCleanup: bypassCleanupOnDispose, realtime: realtime)
         {
             this.bypassCleanupOnSetup = bypassCleanupOnSetup;
diff --git a/osu.Game/Tests/VisualTestRunner.cs b/osu.Game/Tests/VisualTestRunner.cs
index e04c71d193..c6a0eaf9bd 100644
--- a/osu.Game/Tests/VisualTestRunner.cs
+++ b/osu.Game/Tests/VisualTestRunner.cs
@@ -12,7 +12,7 @@ public static class VisualTestRunner
         [STAThread]
         public static int Main(string[] args)
         {
-            using (DesktopGameHost host = Host.GetSuitableDesktopHost(@"osu-development", new HostOptions { BindIPC = true, }))
+            using (DesktopGameHost host = Host.GetSuitableDesktopHost(@"osu-development", new HostOptions { IPCPort = 45356, }))
             {
                 host.Run(new OsuTestBrowser());
                 return 0;

May want to change the visual test runner port to be able to run that independently of game, not sure. The above is the minimal viable.