[API Proposal]: Track Exceptions in flight (information about the state that existed for the thread when the exception occurred)

[Yun-Ting]

Background and motivation

Currently, Marshal.GetExceptionPointers is not supported in native AOT.

See the environment control flag in runtime:

runtime/src/libraries/Common/tests/TestUtilities/System/PlatformDetection.cs

Line 97 in b80048e

public static bool IsMarshalGetExceptionPointersSupported => !IsMonoRuntime && !IsNativeAot;

See open-telemetry/opentelemetry-dotnet#5374 (comment) on how this could be achieved.

API Proposal

Currently, getting in-flight exception is not supported in native AOT:

runtime/src/coreclr/vm/comutilnative.cpp

Line 394 in b80048e

FCIMPL0(EXCEPTION_POINTERS*, ExceptionNative::GetExceptionPointers)

I propose to enable this feature in native AOT:

FCIMPL0(EXCEPTION_POINTERS*, ExceptionNative::GetExceptionPointers)
{
    FCALL_CONTRACT;

    EXCEPTION_POINTERS* retVal = NULL;

    Thread *pThread = GetThread();
    if (pThread->IsExceptionInProgress())
    {
        retVal = pThread->GetExceptionState()->GetExceptionPointers();
    }

    return retVal;
}
FCIMPLEND

API Usage

See this issue: open-telemetry/opentelemetry-dotnet#5358

Alternative Designs

No response

Risks

No response

Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Background and motivation

Currently, Marshal.GetExceptionPointers is not supported in native AOT.

See the environment control flag in runtime:

runtime/src/libraries/Common/tests/TestUtilities/System/PlatformDetection.cs

Line 97 in b80048e

public static bool IsMarshalGetExceptionPointersSupported => !IsMonoRuntime && !IsNativeAot;

See open-telemetry/opentelemetry-dotnet#5374 (comment) on how this could be achieved.

API Proposal

Currently, getting in-flight exception is not supported in native AOT:

runtime/src/coreclr/vm/comutilnative.cpp

Line 394 in b80048e

FCIMPL0(EXCEPTION_POINTERS*, ExceptionNative::GetExceptionPointers)

I propose to enable this feature in native AOT:

FCIMPL0(EXCEPTION_POINTERS*, ExceptionNative::GetExceptionPointers)
{
    FCALL_CONTRACT;

    EXCEPTION_POINTERS* retVal = NULL;

    Thread *pThread = GetThread();
    if (pThread->IsExceptionInProgress())
    {
        retVal = pThread->GetExceptionState()->GetExceptionPointers();
    }

    return retVal;
}
FCIMPLEND

API Usage

See this issue: open-telemetry/opentelemetry-dotnet#5358

Alternative Designs

No response

Risks

No response

Author:	Yun-Ting
Assignees:	-
Labels:	api-suggestion, untriaged, area-NativeAOT-coreclr, needs-area-label
Milestone:	-

[jkotas]

Currently, getting in-flight exception is not supported in native AOT:

The Marshal.GetExceptionPointers API is not the right API to use for your scenario. It is both unnecessarily compilated API to handle your scenario and also not 100% reliable for your scenario as pointed out in open-telemetry/opentelemetry-dotnet#5374 (comment) and our offline discussion.

Could you please describe what you would like to actually achieve in your scenario? We can then work on the design on the right API that is both reliable and not unnecessarily compilated.

[Yun-Ting]

Could you please describe what you would like to actually achieve in your scenario? We can then work on the design on the right API that is both reliable and not unnecessarily compilated.

Hi @jkotas, automatically detect exceptions and set Activity status is what we want to achieve.
See more details here: open-telemetry/opentelemetry-dotnet#1853
Thank you.

[jkotas]

I am not able to figure out the desired expected behavior from this issue and from the code. (I know what your current code does, but I do not think that it is the behavior you actually want.)

Could you please describe the desired behavior? When is ExceptionProcessor expected to call SetStatus(ActivityStatusCode.Error) on the activity?

[MichalStrehovsky]

@reyang or @CodeBlanch could you give us some details on what semantics are needed for tracking exception in flight in OpenTelemetry? This is in reference to open-telemetry/opentelemetry-dotnet#1858. We see Marshal.GetExceptionPointers is used and numerical values it returns are being compared. We don't document the numerical value, only the structure that is pointed by the pointer. It's not clear to us what comparing numerical values is achieving.