From d809cba68d931d68b27bc0ba9534634cac7b35db Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 22 Apr 2026 13:35:01 +0000
Subject: [PATCH] Log every first-chance exception thrown on osu.Framework
 GameThreads

Agent-Logs-Url: https://github.com/winnerspiros/osu/sessions/2e0e3d1e-4954-4a75-be3c-233040b818ef

Co-authored-by: winnerspiros <1675249+winnerspiros@users.noreply.github.com>
---
 osu.Android/CrashDiagnostics.cs | 38 +++++++++++++++++++++++++++++----
 1 file changed, 34 insertions(+), 4 deletions(-)

diff --git a/osu.Android/CrashDiagnostics.cs b/osu.Android/CrashDiagnostics.cs
index 65587a30d7ba..4abf6f0f9111 100644
--- a/osu.Android/CrashDiagnostics.cs
+++ b/osu.Android/CrashDiagnostics.cs
@@ -199,13 +199,24 @@ public static void InstallManagedExceptionHooks()
             // AppDomain.UnhandledException before aborting — so without this hook the
             // exception that ultimately kills the process can vanish without trace. We
             // record it here on every throw so the *last* recorded exception before a
-            // SIGSEGV/SIGABRT is the candidate culprit. To avoid drowning the log in noise
-            // we filter by exception type — only fatal-ish kinds are recorded.
+            // SIGSEGV/SIGABRT is the candidate culprit.
+            //
+            // Filtering policy:
+            //   * On osu.Framework GameThreads (Draw/Update/Audio/Input): log *every*
+            //     exception. An unhandled throw on any of these threads will tear down
+            //     the process via Mono's tgkill(SIGSEGV) path with no managed trace
+            //     reaching AppDomain.UnhandledException, so we cannot afford to filter.
+            //   * On all other threads: keep the legacy "fatal-ish kinds" type filter
+            //     so the log is not flooded by routine first-chance noise (e.g. the
+            //     HidSharp / CFStringCreateWithCharacters EntryPointNotFoundException
+            //     that fires every startup on .NET TP Worker).
             try
             {
                 AppDomain.CurrentDomain.FirstChanceException += (_, e) =>
                 {
-                    if (e.Exception is NullReferenceException
+                    bool isGameThread = isOsuGameThread(Thread.CurrentThread.Name);
+
+                    bool isFatalKind = e.Exception is NullReferenceException
                         or AccessViolationException
                         or StackOverflowException
                         or TypeInitializationException
@@ -215,7 +226,9 @@ or BadImageFormatException
                         or TypeLoadException
                         or MissingMethodException
                         or MissingFieldException
-                        or InvalidProgramException)
+                        or InvalidProgramException;
+
+                    if (isGameThread || isFatalKind)
                     {
                         writeManagedException($"FirstChanceException ({e.Exception.GetType().Name})", e.Exception);
                     }
@@ -227,6 +240,23 @@ or MissingFieldException
             }
         }
 
+        // osu.Framework names its game threads with stable prefixes such as
+        // "DrawThread", "UpdateThread", "AudioThread", "InputThread", and the
+        // tombstone we are debugging shows the comm name "Draw (GameThread)".
+        // Match any of these so an exception thrown deep inside the renderer or
+        // audio pipeline gets captured before Mono aborts the process.
+        private static bool isOsuGameThread(string? name)
+        {
+            if (string.IsNullOrEmpty(name))
+                return false;
+
+            return name.StartsWith("Draw", StringComparison.Ordinal)
+                   || name.StartsWith("Update", StringComparison.Ordinal)
+                   || name.StartsWith("Audio", StringComparison.Ordinal)
+                   || name.StartsWith("Input", StringComparison.Ordinal)
+                   || name.Contains("GameThread", StringComparison.Ordinal);
+        }
+
         /// <summary>
         /// Records a one-line summary of the native handler install state (sentinel exists?
         /// log path?) so the very first thing we see in the log on the next inspection tells