Python has the concept of *unraisable exceptions* - exceptions that cannot be raised at the time they occur because they would break something about the runtime. For example, an exception raised during an object's __del__ method would break garbage collection. Python 3.8 added the ability to take action when unraisable exceptions occur, by setting sys.unraisablehook to a callable ( https://docs.python.org/3.8/library/sys.html#sys.unraisablehook ). I propose that we extend Django's test runner to add such a hook that records if any unraisable exceptions occur during a test run, and fails the test run if this is the case.
The use case I came across for this was using asyncio in debug mode, which warns about unawaited coroutines and unretrieved futures ( https://docs.python.org/3.8/library/asyncio-dev.html#detect-never-awaited-coroutines ). It can be very handy to add a warning filter to turn these RuntimeWarnings into exceptions in tests and development. Unfortunately such exceptions are always (or often?) *unraisable*, so Python prints their stack trace with the default unraisable hook, but carries on as if no error occurred. Failing test runs if unraisable exceptions occur could help highlight such issues. I'm writing to the mailing list because I'm not sure if failing the test run would *always* make sense. Does anyone else have experience with unraisable exceptions? FWIW, pytest has only one stalled discussion: https://github.com/pytest-dev/pytest/issues/5299 -- Adam -- You received this message because you are subscribed to the Google Groups "Django developers (Contributions to Django itself)" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-developers+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/django-developers/CAMyDDM3nN-D3hLhjbWt%2BqGt0xqhho1GVdTrOEdfx2GJ17JVb7Q%40mail.gmail.com.
