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BUG: pytest.raises(HTTPError, match="...") breaks on Python 3.9 + pytest 8.0 #11872
Description
import pytest
from urllib.error import HTTPError
def test_foo():
with pytest.raises(HTTPError, match="Not Found"):
raise HTTPError(code=404, msg="Not Found", fp=None, hdrs=None, url="")this test pass with Python 3.9 + pytest 7.4.4, but fails if I upgrade to pytest 8.0.0
Here's the short traceback (simply running pytest t.py)
========================================= test session starts ==========================================
platform darwin -- Python 3.9.18, pytest-8.0.0, pluggy-1.4.0
rootdir: /private/tmp
collected 1 item
t.py F [100%]
=============================================== FAILURES ===============================================
_______________________________________________ test_foo _______________________________________________
def test_foo():
with pytest.raises(HTTPError, match="Not Found"):
> raise HTTPError(code=404, msg="Not Found", fp=None, hdrs=None, url="")
E urllib.error.HTTPError: HTTP Error 404: Not Found
t.py:5: HTTPError
During handling of the above exception, another exception occurred:
def test_foo():
with pytest.raises(HTTPError, match="Not Found"):
> raise HTTPError(code=404, msg="Not Found", fp=None, hdrs=None, url="")
t.py:5:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
.venv/lib/python3.9/site-packages/_pytest/_code/code.py:704: in _stringify_exception
*getattr(exc, "__notes__", []),
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
self = <HTTPError 404: 'Not Found'>, name = '__notes__'
def __getattr__(self, name):
# Attribute lookups are delegated to the underlying file
# and cached for non-numeric results
# (i.e. methods are cached, closed and friends are not)
> file = self.__dict__['file']
E KeyError: 'file'
/Users/clm/.pyenv/versions/3.9.18/lib/python3.9/tempfile.py:473: KeyError
======================================= short test summary info ========================================
FAILED t.py::test_foo - KeyError: 'file'
========================================== 1 failed in 0.03s ===========================================
And attached, the full-trace (pytest t.py --full-trace)
I haven't bisected yet, but git blame seems to indicate that #11424 is probably the breaking patch
- a detailed description of the bug or problem you are having
- output of
pip listfrom the virtual environment you are using
Package Version
-------------- -------
exceptiongroup 1.2.0
iniconfig 2.0.0
packaging 23.2
pip 23.0.1
pluggy 1.4.0
pytest 8.0.0
setuptools 58.1.0
tomli 2.0.1
- pytest and operating system versions:
see on MacOS 14.3 and Ubuntu 22.04.3, but I don't think that's relevant - minimal example if possible
Activity
neutrinoceros commentedon Jan 28, 2024
given that the exception is raised from
tempfile, I suspect this could be an actual CPython bug.bluetech commentedon Jan 28, 2024
Looks like
getattr(exc, "__notes__", [])is causing issues on this particular exception on Python 3.9 (I verified that this doesn't happen on 3.10 and 3.11). I haven't haven't checked how tempfile is involved yet, probably a urllib thing. The most likely fix is to change this getattr to a safe getattr, but if you're able to analyze the cause more precisely that'd be helpful :)neutrinoceros commentedon Jan 28, 2024
what do you mean by "safe getattr" ?
bluetech commentedon Jan 28, 2024
pytest/src/_pytest/compat.py
Line 277 in 8853a57
glemaitre commentedon Jan 29, 2024
Our CIs tried to bump
pytestand this failure happen on 3.9 only for what it is worth.glemaitre commentedon Jan 29, 2024
and using
safe_getattris solving the issue.glemaitre commentedon Jan 29, 2024
The root cause was probably this bug: python/cpython#98778
tmct commentedon Jan 29, 2024
I'm seeing very similar behaviour for python 3.10 + pytest 8 - it's failing to register that a ValueError has been thrown. Only occurs when I run the whole test suite at once, but then one of my tests (one that uses mocking - not sure if relevant) fails every time. Fine on pytest 7.x.
I'll try to put together a minimal, shareable example if I can.