LastFailure.ErrorType is System.AggregateException when calling async activity with retry handler

[savbace]

Preconditions

• Call activity which returns Task (async) with custom retry handler using TaskOptions.FromRetryHandler.
• The activity throws ApplicationException.
• Use LastFailure.IsCausedBy<ApplicationException>() to check whether need to retry.

Expected result: LastFailure.IsCausedBy<ApplicationException>() returns true;
Actual result: LastFailure.IsCausedBy<ApplicationException>() returns false;

Sample code

public class BackgroundOrchestrationFuncs
{
  [Function(nameof(BackgroundOrchestration))]
  public async Task BackgroundOrchestration([OrchestrationTrigger] TaskOrchestrationContext context)
  {
    var input = context.GetInput<BackgroundOptions>();
    TaskOptions options = TaskOptions.FromRetryHandler(context =>
    {
      if (!context.LastFailure.IsCausedBy<ApplicationException>()) // get false here
      {
        return false;
      }

      return context.LastAttemptNumber < 3;
    });

    await context.CallActivityAsync(nameof(RiskyActivity), input, options);
  }

  [Function(nameof(RiskyActivity))]
  public async Task RiskyActivity([ActivityTrigger] BackgroundOptions options)
  {
    await Task.Delay(3000);
    throw new ApplicationException("Failed to run!");
  }
}

Details
LastFailure contains information about System.AggregateException instead of ApplicationException when activity function is asynchronous.
From the other side if activity function is synchronous then LastFailure contains expected information about ApplicationException.
Repo for reproducing the issue: DurableRetryPlayground
Here is a value of LastFailure during debug session from the repo:

LastFailure	{System.AggregateException: One or more errors occurred. (Failed to run!)}	Microsoft.DurableTask.TaskFailureDetails
	EqualityContract	{Name = "TaskFailureDetails" FullName = "Microsoft.DurableTask.TaskFailureDetails"}	System.Type {System.RuntimeType}
	ErrorMessage	"One or more errors occurred. (Failed to run!)"	string
	ErrorType	"System.AggregateException"	string
	InnerFailure	null	Microsoft.DurableTask.TaskFailureDetails
	StackTrace	"   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)\r\n   at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)\r\n   at System.Threading.Tasks.Task`1.get_Result()\r\n   at Microsoft.Azure.Functions.Worker.Invocation.DefaultFunctionInvoker`2.<>c.<InvokeAsync>b__6_0(Task`1 t) in D:\\a\\_work\\1\\s\\src\\DotNetWorker.Core\\Invocation\\DefaultFunctionInvoker.cs:line 32\r\n   at System.Threading.Tasks.ContinuationResultTaskFromResultTask`2.InnerInvoke()\r\n   at System.Threading.Tasks.Task.<>c.<.cctor>b__272_0(Object obj)\r\n   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)\r\n--- End of stack trace from previous location ---\r\n   at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot, Thread threadPoolThread)\r\n--- End of stack trace from previous location ---\r\n   at Microsoft.Azure.Functions.Worker.Invocation.DefaultFunctionExecutor.ExecuteAsync(FunctionContext context) in D:\\a\\_work\\1\\s\\src\\DotNetWorker.Core\\Invocation\\DefaultFunctionExecutor.cs:line 45\r\n   at Microsoft.Azure.Functions.Worker.OutputBindings.OutputBindingsMiddleware.Invoke(FunctionContext context, FunctionExecutionDelegate next) in D:\\a\\_work\\1\\s\\src\\DotNetWorker.Core\\OutputBindings\\OutputBindingsMiddleware.cs:line 13\r\n   at Microsoft.Azure.Functions.Worker.Extensions.DurableTask.DurableTaskFunctionsMiddleware.Invoke(FunctionContext functionContext, FunctionExecutionDelegate next) in /_/src/Worker.Extensions.DurableTask/DurableTaskFunctionsMiddleware.cs:line 22\r\n   at Microsoft.Azure.Functions.Worker.FunctionsApplication.InvokeFunctionAsync(FunctionContext context) in D:\\a\\_work\\1\\s\\src\\DotNetWorker.Core\\FunctionsApplication.cs:line 77\r\n   at Microsoft.Azure.Functions.Worker.Handlers.InvocationHandler.InvokeAsync(InvocationRequest request) in D:\\a\\_work\\1\\s\\src\\DotNetWorker.Grpc\\Handlers\\InvocationHandler.cs:line 88"	string

Could you please clarify whether my expectations are correct?

[jviau]

This is a behavior of the functions dotnet worker: Azure/azure-functions-dotnet-worker#993

[savbace]

@jviau oh, I see. Thanks for pointing out the original issue! Closing this ticket then.