.NET 6 iOS support

[bruno-garcia]

Since .NET 6 landed (#939 ) we can look into adding net6-ios and including sentry-cocoa.
See: https://github.com/xamarin/xamarin-macios/blob/861c40dbe45478b848ac1d165314e05de012bf0f/tests/dotnet/NativeXCFrameworkReferencesApp/shared.csproj

When we bundle the Sentry iOS SDK we need to take into account that Mono uses some signals to interpret NullReferenceExceptions and need special case (run before other crash reports do):

See: https://www.mono-project.com/docs/advanced/signals/#incomplete-solution
See also: dotnet/runtime#44736

This is probably something we can do in the binding project, before calling Init in the iOS SDK.

Proposed solution, based on the Mono docs:

try {
} finally {
    Mono.Runtime.RemoveSignalHandlers ();
    try {
        // Init the Sentry iOS SDK:
        SentrySDK.start(...);
    } finally {
        Mono.Runtime.InstallSignalHandlers ();
    }
}

Since Mono’s signal handlers are reinstalled and not restored, Mono will now chain to the signal handlers installed by EnableCrashReporting.

The code is executed in a finally block, so that the Mono runtime will never abort it under any circumstance.

It’s recommended to do this as early as possible when launching the process, in particular before starting any secondary threads. If any signals are raised between removing and reinstalling Mono’s signal handlers (this includes NullReferenceExceptions), the app will crash.

• Make sure native debug symbols are bundled in the NuGet package. See: Clarification: Debug Symbols for Binding Library dotnet/macios#9934 (comment)

See: https://www.mono-project.com/docs/advanced/signals/#complete-solution

[gsomix]

@lucas-zimerman Hey, any news on it?

[lucas-zimerman]

@lucas-zimerman Hey, any news on it?

Currently, it's on hold but we'll return to it near to MAUI release date.

[bruno-garcia]

@gsomix anything specific you're looking for?

The SDK should work on iOS, just not capturing native crashes

[Dolfik1]

The SDK should work on iOS, just not capturing native crashes

This is the main problem. Native crashes are also very useful information. Many native crashes can be caused by managed code.

It would also be important to have information about the platform, device model, os version, cpu model, etc. This is important especially on Android.

[Dolfik1]

I also want to draw attention to an exception in the getsentry/sentry-xamarin#97

This exception is thrown inside sentry-dotnet:
https://github.com/getsentry/sentry-dotnet/blob/main/src/Sentry/Internal/Http/DefaultSentryHttpClientFactory.cs#L34

I don't know how this used to work, but the Xamarin.iOS implementation of HttpClient does not have an implementation for SupportsAutomaticDecompression:
https://github.com/xamarin/xamarin-macios/blob/main/src/Foundation/NSUrlSessionHandler.cs#L599
dotnet/macios#13579

I checked our project (old Xamarin.iOS) and it uses NSUrlSessionHandler as default handler:

<MtouchHttpClientHandler>NSUrlSessionHandler</MtouchHttpClientHandler>

But it stopped working after porting the project to .Net 6 (getsentry/sentry-xamarin#97)

The recommended handler is NSUrlSessionHandler. You can read more about HTTP stack on iOS:
https://docs.microsoft.com/en-us/xamarin/cross-platform/macios/http-stack

So it seems that the problem is really in sentry-dotnet.

[bruno-garcia]

It seems the problem is really in .NET 6 in this case. In the iOS implementation, that's throwing:

Unhandled managed exception: Operation is not supported on this platform. 
(System.PlatformNotSupportedException)
   at System.Net.Http.NSUrlSessionHandler.get_SupportsAutomaticDecompression()

Perhaps disabling compression on the client could be a work around

[bruno-garcia]

The Sentry.Xamarin package relies on Xamarin.Essentials which is now part of .NET MAUI. So we could add the device information bits for MAUI (on a Sentry.Maui) but I don't believe we'll go through the effort of adding #if throughout and call into MonoTouch and Xamarin.Android APIs to get device data (basically replicating what Essentials does).

That said improving support (including a work around so that it doesn't throw when using a net6 iOS build) is needed here and we'd love to get come contributions