Stack Trace missing for NativeAOT App

[emrys90]

Package

Sentry

.NET Flavor

.NET Core

.NET Version

8.0

OS

Linux

SDK Version

4.7.0

Self-Hosted Sentry Version

24.6.0

Steps to Reproduce

I'm having an issue where the client is not exporting stack traces to the API for a NativeAOT compiled app. Works fine in a non-NativeAOT app.

Expected Result

Event is sent with stack traces.

Actual Result

Event is sent with no stack traces.

[jamescrosswell]

I played around to try to reproduce this with the following program. There is a stack trace, but it only has one frame, and that doesn't appear to be anything to do with Sentry (note the Console.WriteLine statements in the catch block):

SentrySdk.Init(options =>
{
    options.Dsn = "...YOUR DSN HERE...";
    options.IsGlobalModeEnabled = true;
    options.TracesSampleRate = 1.0;
});

Console.WriteLine("Starting transaction...");

var transaction = SentrySdk.StartTransaction("Program Main", "function");
SentrySdk.ConfigureScope(scope => scope.Transaction = transaction);

await ParentFunction();

transaction.Finish();
Console.WriteLine("Transaction Finished!");
return;

async Task ParentFunction()
{
    await Task.Delay(500);
    await RecursiveFunction(5);
}

async Task RecursiveFunction(int depth)
{
    var span = transaction.StartChild("function", nameof(RecursiveFunction));

    try
    {
        // Throw an exception
        if (depth <= 0)
        {
            throw new ApplicationException("Something happened!");
        }
        await RecursiveFunction(depth - 1);
        span.Finish();
    }
    catch (Exception exception)
    {
        // This is an example of capturing a handled exception.
        Console.WriteLine($"Capturing exception: {exception.Message}");
        Console.WriteLine(exception.StackTrace);
        SentrySdk.CaptureException(exception);
        span.Finish(exception);
    }
}

And what I see as output:

Starting transaction...
Capturing exception: Something happened!
   at Program.<>c__DisplayClass0_0.<<<Main>$>g__RecursiveFunction|3>d.MoveNext() in /Users/jamescrosswell/code/ConsoleAot/Program.cs:line 35
Transaction Finished!

This appears to be a limitation of AOT then.

[jamescrosswell]

Ah, interestingly if I remove the try...catch block and just let the exception surface, we capture the native exception and for that we get a full stack trace.

SentrySdk.Init(options =>
{
    options.Dsn = "...YOUR DSN HERE...";
    options.IsGlobalModeEnabled = true;
    options.TracesSampleRate = 1.0;
});

Console.WriteLine("Starting transaction...");

var transaction = SentrySdk.StartTransaction("Program Main", "function");
SentrySdk.ConfigureScope(scope => scope.Transaction = transaction);

ParentFunction();

transaction.Finish();
Console.WriteLine("Transaction Finished!");
return;

void ParentFunction()
{
    RecursiveFunction(5);
}

void RecursiveFunction(int depth)
{
    var span = transaction.StartChild("function", nameof(RecursiveFunction));

    // Throw an exception
    if (depth <= 0)
    {
        throw new ApplicationException("Something happened!");
    }
    RecursiveFunction(depth - 1);
    span.Finish();
}

And here's the output from that:

Starting transaction...
Unhandled exception. System.ApplicationException: Something happened!
   at Program.<>c__DisplayClass0_0.<<Main>$>g__RecursiveFunction|3(Int32 depth) in /Users/jamescrosswell/code/ConsoleAot/Program.cs:line 32
   at Program.<>c__DisplayClass0_0.<<Main>$>g__RecursiveFunction|3(Int32 depth) in /Users/jamescrosswell/code/ConsoleAot/Program.cs:line 32
   at Program.<>c__DisplayClass0_0.<<Main>$>g__RecursiveFunction|3(Int32 depth) in /Users/jamescrosswell/code/ConsoleAot/Program.cs:line 32
   at Program.<>c__DisplayClass0_0.<<Main>$>g__RecursiveFunction|3(Int32 depth) in /Users/jamescrosswell/code/ConsoleAot/Program.cs:line 32
   at Program.<>c__DisplayClass0_0.<<Main>$>g__RecursiveFunction|3(Int32 depth) in /Users/jamescrosswell/code/ConsoleAot/Program.cs:line 32
   at Program.<>c__DisplayClass0_0.<<Main>$>g__RecursiveFunction|3(Int32 depth) in /Users/jamescrosswell/code/ConsoleAot/Program.cs:line 32
   at Program.<>c__DisplayClass0_0.<<Main>$>g__ParentFunction|2() in /Users/jamescrosswell/code/ConsoleAot/Program.cs:line 21
   at Program.<Main>$(String[] args) in /Users/jamescrosswell/code/ConsoleAot/Program.cs:line 13
zsh: abort      ./bin/Release/net8.0/osx-arm64/ConsoleAot

[emrys90]

There are other work arounds as well for getting a stack trace on NativeAOT. If you do exception.StackTrace.ToString() it'll give a result that can be attempted to be parsed. Not sure if there's a better way to handle it or not.

I'm switching to Sentry from BugSnag, and they did have stack traces for my NativeAOT app.

[jamescrosswell]

If you do exception.StackTrace.ToString() it'll give a result that can be attempted to be parsed. Not sure if there's a better way to handle it or not.

We can't really use StackTrace.ToString(). That's missing loads of information that we need to do things like generating Enhanced Stack Frames. If you did want to capture this though, you could easily do this in the options... something like:

    options.SetBeforeSend(ev =>
    {
        if (ev.Exception is { } exception)
        {
            ev.SetExtra("Stack Trace", $"{exception.StackTrace}");
        }
        return ev;
    });

We did open a discussion with Microsoft about this and it looks like there might be something coming in net9.0 that will help.

I'm switching to Sentry from BugSnag, and they did have stack traces for my NativeAOT app.

I tried the sample applications a copied/pasted above with BugSnag and saw exactly the same results. If I do a try...catch followed by a bugsnag.Notify then I only see a single line in the stack trace on BugSnag. On the other hand, if I let the exception bubble up, a full native stack trace is captured (although the application obviously terminates in this case).

If you've got an example of something that BugSnag is capturing but Sentry is not, I'd love to learn more.

[emrys90]

Hmm weird, I was just doing a Bugsnag.Notify(exception, Severity.Error) and it would capture stack traces, just not line numbers.

[emrys90]

To work around this issue I'm trying out the ISentryStackTraceFactory interface set through: options.UseStackTraceFactory(new NativeAotStackTraceFactory());

Do you see any potential issues with how I'm doing this? Here's an example of the stack trace:

   at System.Exception.SetCurrentStackTrace() + 0x63
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.SetCurrentStackTrace(Exception) + 0x18
   at ProjectCards.Utility.ConsoleLogger.WriteLog(NetLogLevel, String) + 0x1b7
   at ProjectCards.Utility.LogExtensions.WriteLog(NetLogLevel, String, String, Int32, String) + 0x2f9
   at ProjectCards.Networking.NetworkAuthenticator.<AfterUserLoaded>d__2.MoveNext() + 0x3ab

    public class NativeAotStackTraceFactory : ISentryStackTraceFactory
    {
        public SentryStackTrace Create(Exception exception = null)
        {
            Console.WriteLine("Source Stack Trace: " + exception?.StackTrace);

            var trace = new SentryStackTrace();
            var frames = new List<SentryStackFrame>();

            var lines = exception?.StackTrace?.Split(System.Environment.NewLine) ?? Array.Empty<string>();
            foreach (var line in lines)
            {
                var match = Regex.Match(line, @"at (.+)\.(.+) \+");
                if (match.Success)
                {
                    frames.Add(new SentryStackFrame()
                    {
                        Module = match.Groups[1].Value,
                        Function = match.Groups[2].Value
                    });
                }
                else
                {
                    Console.WriteLine($"Regex match failed for: {line}");
                    frames.Add(new SentryStackFrame()
                    {
                        Function = line
                    });
                }
            }

            trace.Frames = frames;
            return trace;
        }
    }

[bitsandfoxes]

Do you see any potential issues with how I'm doing this?

I actually don't. @jamescrosswell would this be a valid workaround we could put into the SDK when we know we don't get anything better?

[jamescrosswell]

Do you see any potential issues with how I'm doing this?

I actually don't. @jamescrosswell would this be a valid workaround we could put into the SDK when we know we don't get anything better?

As a fallback, it might be great 🚀 We may or may not be able to get it to work with things like InApp frame detection and pretty sure we can't do fancy stuff like Enhanced stack traces and source mapping but it'd be a hell of a lot better than nothing right?

btw: Apologies for the delay - I've been out sick 😷.

[filipnavara]

The .NET 9 DiagnosticMethodInfo API has landed, btw. It would be nice to test it before it gets released later this year to be sure there's no bugs or functionality gaps.