Configuration error handling in pytest plugins

[bwoodsend]

In the event that a pytest plugin realises that it has been misconfigured, is there a defacto way in which it should report that information to the user? For example,

def pytest_collection_modifyitems(session, config, items):
    some_setting = config.getini("some-setting")
    if some_setting doesn't make sense:
        # What should go here to either abort the test run or propagate into a meaningful warning?

My initial instinct was just to raise an exception but doing so leads to a stacktrace being dumped with the prefix INTERNALERROR> all over it, then tests continuing as usual which incorrectly hints that something is broken deep in the bowels of pytest rather than in the user's setup.

[nicoddemus]

Try raising pytest.UsageError, we catch this at the top level and produce a shorter message.

[bwoodsend]

Oh, I do like the way pytest seems to think of everything 🙂