Getting StackTrace to print on an unhandled exception

[xforever1313]

Hey everyone!

I've recently been playing around with Cake.Frosting (version 1.1.0), and have been loving it. But I have a use case that I have a "workaround" for, and I was wondering if there was a less hacky way to do it.

The thing I'm looking for is, on an Unhanded Exception in Run(), I would like the entire stack trace to print out, even if the verbosity is not originally set to diagnostic. At the moment, the stack trace only seems to print out on an error if the verbosity is set to Diagnostic. It makes sense why it does this. While we could just hard-code the verbosity at the start when creating the CakeHost object, it could mean a lot of unneeded output 99% of the time, which isn't ideal for the environment I work in.

This is a sample class I have:

[TaskName( "some_task" )]
public class SomeTask : FrostingTask
{
    public override void Run( ICakeContext context )
    {
        Func1();
    }

    private void Func1()
    {
        Func2();
    }

    private void Func2()
    {
        throw new Exception( "Oops" );
    }

    public override void OnError( Exception exception, ICakeContext context )
    {
        // Something
    }
}

I tried this at first on OnError, but the issue with this method is CakeHost.Run() returns with a zero exit code:

public override void OnError( Exception exception, ICakeContext context )
{
    context.Error( exception.ToString() );
    base.OnError( exception, context );
}

and this is what's printed out:

> .\FrostingTest.exe --target=some_task

========================================
some_task
========================================
An error occurred when executing task 'some_task'.
System.Exception: Oops
   at FrostingTest.SomeTask.Func2() in <redacted>:line 41
   at FrostingTest.SomeTask.Func1() in <redacted>:line 36
   at FrostingTest.SomeTask.Run(ICakeContext context) in <redacted>:line 31
   at Cake.Frosting.FrostingTask`1.Cake.Frosting.IFrostingTask.RunAsync(ICakeContext context)
   at Cake.Core.CakeTask.Execute(ICakeContext context)
   at Cake.Core.DefaultExecutionStrategy.ExecuteAsync(CakeTask task, ICakeContext context)
   at Cake.Core.CakeEngine.ExecuteTaskAsync(ICakeContext context, IExecutionStrategy strategy, Stopwatch stopWatch, CakeTask task, CakeReport report)

Task                          Duration
--------------------------------------------------
some_task                     00:00:00.0471202
--------------------------------------------------
Total:                        00:00:00.0471202
> echo $LASTEXITCODE
0

Next thing I tried was just re-throwing the exception after enabling DiagnosticVerbosity. This was closer to what I wanted, other than the stack trace starting on OnError(), not the origin point.

public override void OnError( Exception exception, ICakeContext context )
{
    context.DiagnosticVerbosity();
    throw exception;
}

> .\FrostingTest.exe --target=some_task

========================================
some_task
========================================
An error occurred when executing task 'some_task'.
Error: System.Exception: Oops
   at FrostingTest.SomeTask.OnError(Exception exception, ICakeContext context) in <redacted>:line 53
   at Cake.Frosting.FrostingTask`1.Cake.Frosting.IFrostingTask.OnError(Exception exception, ICakeContext context)
   at Cake.Frosting.Internal.FrostingEngine`1.<>c__DisplayClass15_0.<ConfigureTasks>b__0(Exception exception)
   at Cake.Core.CakeTaskBuilderExtensions.<>c__DisplayClass15_0.<OnError>b__0(Exception exception, ICakeContext context)
   at Cake.Core.CakeTaskExtensions.<>c__DisplayClass3_0.<<SetErrorHandler>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at Cake.Core.DefaultExecutionStrategy.HandleErrorsAsync(Func`3 action, Exception exception, ICakeContext context)
   at Cake.Core.CakeEngine.HandleErrorsAsync(IExecutionStrategy strategy, Func`3 errorHandler, Exception exception, ICakeContext context)
   at Cake.Core.CakeEngine.ExecuteTaskAsync(ICakeContext context, IExecutionStrategy strategy, Stopwatch stopWatch, CakeTask task, CakeReport report)
   at Cake.Core.CakeEngine.ExecuteTaskAsync(ICakeContext context, IExecutionStrategy strategy, Stopwatch stopWatch, CakeTask task, CakeReport report)
   at Cake.Core.CakeEngine.RunTask(ICakeContext context, IExecutionStrategy strategy, CakeTask task, String target, Stopwatch stopWatch, CakeReport report)
   at Cake.Core.CakeEngine.RunTargetAsync(ICakeContext context, IExecutionStrategy strategy, ExecutionSettings settings)
   at Cake.Cli.BuildScriptHost`1.RunTargetAsync(String target)
   at Cake.Core.Scripting.ScriptHost.RunTarget(String target)
   at Cake.Frosting.Internal.FrostingEngine`1.Run(String target)
   at Cake.Frosting.Internal.DefaultCommand.Execute(CommandContext context, DefaultCommandSettings settings)
> echo $LASTEXITCODE
-1

The solution I found in the end was this, as this prints the correct stack trace, exits with a non-zero exit code.:

public override void OnError( Exception exception, ICakeContext context )
{
    // We want the stack trace to print out when all is said and done.
    // The way to do this is to set the verbosity to the maximum,
    // and then re-throw the exception.  Use the weird DispatchInfo
    // class so we don't get a new stack trace.
    // We need to re-throw the exception, or cake will exit with a zero exit code.
    context.DiagnosticVerbosity();
    ExceptionDispatchInfo.Capture( exception ).Throw();
}

> .\FrostingTest.exe --target=some_task

========================================
some_task
========================================
An error occurred when executing task 'some_task'.
Error: System.Exception: Oops
   at FrostingTest.SomeTask.Func2() in <redacted>:line 42
   at FrostingTest.SomeTask.Func1() in <redacted>:line 37
   at FrostingTest.SomeTask.Run(ICakeContext context) in <redacted>:line 32
   at Cake.Frosting.FrostingTask`1.Cake.Frosting.IFrostingTask.RunAsync(ICakeContext context)
   at Cake.Core.CakeTask.Execute(ICakeContext context)
   at Cake.Core.DefaultExecutionStrategy.ExecuteAsync(CakeTask task, ICakeContext context)
   at Cake.Core.CakeEngine.ExecuteTaskAsync(ICakeContext context, IExecutionStrategy strategy, Stopwatch stopWatch, CakeTask task, CakeReport report)
   at FrostingTest.SomeTask.OnError(Exception exception, ICakeContext context) in <redacted>:line 53
   at Cake.Frosting.FrostingTask`1.Cake.Frosting.IFrostingTask.OnError(Exception exception, ICakeContext context)
   at Cake.Frosting.Internal.FrostingEngine`1.<>c__DisplayClass15_0.<ConfigureTasks>b__0(Exception exception)
   at Cake.Core.CakeTaskBuilderExtensions.<>c__DisplayClass15_0.<OnError>b__0(Exception exception, ICakeContext context)
   at Cake.Core.CakeTaskExtensions.<>c__DisplayClass3_0.<<SetErrorHandler>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at Cake.Core.DefaultExecutionStrategy.HandleErrorsAsync(Func`3 action, Exception exception, ICakeContext context)
   at Cake.Core.CakeEngine.HandleErrorsAsync(IExecutionStrategy strategy, Func`3 errorHandler, Exception exception, ICakeContext context)
   at Cake.Core.CakeEngine.ExecuteTaskAsync(ICakeContext context, IExecutionStrategy strategy, Stopwatch stopWatch, CakeTask task, CakeReport report)
   at Cake.Core.CakeEngine.ExecuteTaskAsync(ICakeContext context, IExecutionStrategy strategy, Stopwatch stopWatch, CakeTask task, CakeReport report)
   at Cake.Core.CakeEngine.RunTask(ICakeContext context, IExecutionStrategy strategy, CakeTask task, String target, Stopwatch stopWatch, CakeReport report)
   at Cake.Core.CakeEngine.RunTargetAsync(ICakeContext context, IExecutionStrategy strategy, ExecutionSettings settings)
   at Cake.Cli.BuildScriptHost`1.RunTargetAsync(String target)
   at Cake.Core.Scripting.ScriptHost.RunTarget(String target)
   at Cake.Frosting.Internal.FrostingEngine`1.Run(String target)
   at Cake.Frosting.Internal.DefaultCommand.Execute(CommandContext context, DefaultCommandSettings settings)
   
> echo $LASTEXITCODE
-1

What I don't like about this solution is, while it works, it means that all of my tasks either need to override OnError like this, or inherit from a base class that does. It also means not disposing an IDisposable returned from DiasnosticVerbosity (though I'm not sure how much I care about that since we Errored anyways). Is there some kind of configuration or something I can do to turn on to always print out the stack trace on an error case regardless of verbosity? Or is this the only solution there is? Admittedly, its not the end-of-the-world if there's not :P.

Thanks!