pytest-dev
ExceptionInfo.value not available if pytest.raises fails
When pytest.raise fails, exc_info.value is not available.
def test():
try:
with pytest.raises(AssertionError) as exc_info:
raise Exception()
except Exception as e:
exc_info.value
pass
I get this error
test_testchecks.py:33: in test
exc_info.value
/home/dani/.virtualenvs/sc-tools--PFlaRe2/lib/python3.13/site-packages/_pytest/_code/code.py:607: in value
assert self._excinfo is not None, (
^^^^^^^^^^^^^^^^^^^^^^^^^
E AssertionError: .value can only be used after the context manager exits
pytest 8.4.0
Python 3.13.3
Ubuntu 25.04
pytest.raises reraises the exception if it fails to catch it, and you're catching it with except Exception as e:, so just replace exc_info.value with e and you're good. There's no reason to access it through exc_info.value
(not a regression from 8.4)
Hi, thanks,
just replace exc_info.value with e and you're good
Not quite, what I need is my exception raised within pytest.raise context, not the exception pytest raises.
not a regression from 8.4
Not in this simplified case, but for instance when expected_exception matches but the regex doesn't, this worked in pytest 8.3.5
Hi, thanks,
just replace exc_info.value with e and you're good
Not quite, what I need is my exception raised within pytest.raise context, not the exception pytest raises.
in your example pytest doesn't raise any exception until you try to access exc_info.value, the original exception passes through pytest.raises without being modified.
not a regression from 8.4
Not in this simplified case, but for instance when expected_exception matches but the regex doesn't, this worked in pytest 8.3.5
Ah true, that is a regression. And it might make sense to make your original example work at the same time.
See https://github.com/pytest-dev/pytest/issues/13286 for more discussion on what should be raised when.
When raises isn't matching it isn't providing data
Else malformed code easily working by accident and mixing up boundaries
Ah yeah. The original example also breaks typing, pytest.raises(T).__enter__() -> ContextManager[ExceptionInfo[T]].
Not in this simplified case, but for instance when expected_exception matches but the regex doesn't, this worked in pytest 8.3.5
Previous logic definitely filled exc_info before checking match. It's possible that was simply a byproduct of making use of ExceptionInfo for doing the matching, but I suppose we can restore that functionality.
https://github.com/pytest-dev/pytest/blob/b55ab2aabb68c0ce94c3903139b062d0c2790152/src/_pytest/python_api.py#L1011-L1028
I believe this is a artifact of how match was implemented
Its definitely a bug that this was possible to begin with
If it's indeed a regression id like to warn about using it like that