feat: auto-suppress SIGABRT for uncaught managed exceptions on iOS

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Features
+
+- Auto-suppress `SIGABRT` for uncaught managed exceptions on iOS ([#4523](https://github.com/getsentry/sentry-dotnet/pull/4523))
+
 ### Fixes
 
 - Fail when building Blazor WASM with Profiling. We don't support profiling in Blazor WebAssembly projects. ([#4512](https://github.com/getsentry/sentry-dotnet/pull/4512))

src/Sentry/Platforms/Cocoa/RuntimeMarshalManagedExceptionIntegration.cs

@@ -32,6 +32,11 @@ internal void Handle(object sender, MarshalManagedExceptionEventArgs e)
 
         if (e.Exception is { } ex)
         {
+            // The Obj-C runtime is about to abort. Tag the upcoming duplicate native SIGABRT event for filtering it
+            // out in ProcessOnBeforeSend.
+            // TODO: define "_captured_by_sentry-dotnet" as a constant somewhere
+            SentryCocoaSdk.ConfigureScope(scope => scope.SetTagValue("SIGABRT", "_captured_by_sentry-dotnet"));
+
             ex.SetSentryMechanism(
                 "Runtime.MarshalManagedException",
                 "This exception was caught by the .NET Runtime Marshal Managed Exception global error handler. " +

src/Sentry/Platforms/Cocoa/SentryOptions.cs

@@ -207,11 +207,12 @@ internal NativeOptions(SentryOptions options)
         /// convenient.
         /// </para>
         /// <para>
+        /// TODO: Explain auto (null) vs. true vs. false.
         /// Enabling this may prevent the capture of SIGABRT originating from native (not managed) code... so it may
         /// prevent the capture of genuine native SIGABRT errors.
         /// </para>
         /// </summary>
-        public bool SuppressSignalAborts { get; set; } = false;
+        public bool? SuppressSignalAborts { get; set; } = null;
 
         /// <summary>
         /// <para>

src/Sentry/Platforms/Cocoa/SentrySdk.cs

@@ -200,25 +200,28 @@ private static CocoaSdk.SentryHttpStatusCodeRange[] GetFailedRequestStatusCodes(
     /// </summary>
     internal static CocoaSdk.SentryEvent? ProcessOnBeforeSend(SentryOptions options, CocoaSdk.SentryEvent evt, IHub hub)
     {
-        if (hub is DisabledHub)
-        {
-            return evt;
-        }
-
         // When we have an unhandled managed exception, we send that to Sentry twice - once managed and once native.
         // The managed exception is what a .NET developer would expect, and it is sent by the Sentry.NET SDK
         // But we also get a native SIGABRT since it crashed the application, which is sent by the Sentry Cocoa SDK.
 
         // There should only be one exception on the event in this case
-        if ((options.Native.SuppressSignalAborts || options.Native.SuppressExcBadAccess) && evt.Exceptions?.Length == 1)
+        if (evt.Exceptions?.Length == 1)
         {
             // It will match the following characteristics
             var ex = evt.Exceptions[0];
 
+            // TODO: define "_captured_by_sentry-dotnet" as a constant somewhere
+            if (options.Native.SuppressSignalAborts == null && ex.Type == evt.Tags?["_captured_by_sentry-dotnet"]?.ToString())
+            {
+                options.LogDebug("Discarded {0} error ({1}). Captured as managed exception instead.", ex.Type,
+                    ex.Value);
+                return null;
+            }
+
             // Thankfully, sometimes we can see Xamarin's unhandled exception handler on the stack trace, so we can filter
             // them out. Here is the function that calls abort(), which we will use as a filter:
             // https://github.com/xamarin/xamarin-macios/blob/c55fbdfef95028ba03d0f7a35aebca03bd76f852/runtime/runtime.m#L1114-L1122
-            if (options.Native.SuppressSignalAborts && ex.Type == "SIGABRT" && ex.Value == "Signal 6, Code 0" &&
+            if (options.Native.SuppressSignalAborts == true && ex.Type == "SIGABRT" && ex.Value == "Signal 6, Code 0" &&
                 ex.Stacktrace?.Frames.Any(f => f.Function == "xamarin_unhandled_exception_handler") is true)
             {
                 // Don't send it
@@ -239,6 +242,11 @@ private static CocoaSdk.SentryHttpStatusCodeRange[] GetFailedRequestStatusCodes(
             }
         }
 
+        if (hub is DisabledHub)
+        {
+            return evt;
+        }
+
         // We run our SIGABRT checks first before running managed processors.
         // Because we delegate to user code, we need to catch/log exceptions.
         try