Error during ParallelLoop or parallel returns unhelp error message

[clarklemke]

🐛 Bug Report

If an op fails (for whatever reason) inside a parallel loop, the return error is child call failed but does not provide any traceback or other information regarding the cause of the fail. This makes development on parallel ops frustrating as one has to refactor to a serial loop in order to determine the cause of the failure.

There's a slack message outlining a way to debug but doesn't actually fix the problem.

To Reproduce

1. Write an op with a parallel loop that one of the child steps fails
2. Will result in child call failed error

Expected behavior

An op with a failure inside a parallel loop would function like other failurs: output the cause of the error to the command line.

Actual Behavior

An op inside a parallel loop outputs child call failed error regardless of cause.

[chrisdostert]

@clarklemke Release 0.1.50 included some fixes for error logging. Could you see if you're still hitting this with latest? If so could you do us a favor and post an op that repros this behavior? If not we'll close this out as resolved.