Break debugger on exceptions that aren't handled inside a pytest test

[madig]

When running "Debug Test" from the code edit view, the test output pane shows me pytest's error message when it encounters an uncaught exception, but I would like it to launch a debugger instead. I currently have to insert a try/catch with a breakpoint() otherwise.

I actually feel this should have been requested already but could find neither an issue nor a setting for this...

[int19h]

The problem here is that we're not treating the exception is uncaught. I think this is because it's caught by pytest.

However, pytest is library code, not user code; and we run with "justMyCode": true by default. Thus, if the exception escapes to library code with no possibility that it might flow back into user code, we should consider it as unhandled. For example, we can walk the stack and see if there are any frames below pytest that are user code.

@fabioz, does this sound feasible?

[int19h]

@madig As a partial workaround, you can try checking "Raised exceptions" in the Breakpoints pane. The downside is that it'll also report exceptions that you throw and then handle in your code.

[fabioz]

I've renamed from my understanding of the request (please correct it if I understood wrong).

Well, the problem is that technically this isn't an uncaught exception (because as @int19h mentioned, it's caught by pytest)...

I don't think it's feasible to report it as uncaught before actually being uncaught (this isn't the actual semantic of uncaught exceptions and breaking it makes the handling quite tricky)... maybe it'd be possible to have a test unhandled exception which reports if the exception is raised when a test method exists?

[karthiknadig]

There is userUnhandled mode when setting extension breakpoints. I think we could make use of it instead. VS 2017/2019 supports this, and for VSC we could also provide it as an additional checkbox. Currently we translate userUnhandled to unhandled for VS.
https://microsoft.github.io/debug-adapter-protocol/specification#Types_ExceptionBreakMode

[fabioz]

Ok, I'll try to come up with a proper implementation for userUnhandled as it seems like it'd solve this use case.

[karthiknadig]

/cc @rchiodo

[jekbradbury]

Any updates? I find myself wanting this functionality just about every day... 🙂

[fabioz]

Not yet (I have 2 other issues in the queue before getting this one, so, I'd say I'll probably get to it in a couple of weeks).

[fabioz]

Note: I'm starting to take a look at this now.