Using 'filterwarnings' hides ModuleNotFoundErrors #9218
Description
From time to time on https://github.com/pypa/warehouse, we have an issue where pytest invocation fails due to ModuleNotFoundErrors in our source, but the actual ModuleNotFoundError is hidden by our usage of filterwarnings.
Our pyproject.toml configuration specifies a warning to ignore:
[tool.pytest.ini_options]
filterwarnings = [
'ignore::warehouse.packaging.services.InsecureStorageWarning',
]Invoking pytest raises an exception:
$ python -m pytest
Traceback (most recent call last):
File "/usr/local/lib/python3.8/runpy.py", line 193, in _run_module_as_main
return _run_code(code, main_globals, None,
File "/usr/local/lib/python3.8/runpy.py", line 86, in _run_code
exec(code, run_globals)
File "/opt/warehouse/lib/python3.8/site-packages/pytest/__main__.py", line 5, in <module>
raise SystemExit(pytest.console_main())
File "/opt/warehouse/lib/python3.8/site-packages/_pytest/config/__init__.py", line 185, in console_main
code = main()
File "/opt/warehouse/lib/python3.8/site-packages/_pytest/config/__init__.py", line 143, in main
config = _prepareconfig(args, plugins)
File "/opt/warehouse/lib/python3.8/site-packages/_pytest/config/__init__.py", line 318, in _prepareconfig
config = pluginmanager.hook.pytest_cmdline_parse(
File "/opt/warehouse/lib/python3.8/site-packages/pluggy/_hooks.py", line 265, in __call__
return self._hookexec(self.name, self.get_hookimpls(), kwargs, firstresult)
File "/opt/warehouse/lib/python3.8/site-packages/pluggy/_manager.py", line 80, in _hookexec
return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
File "/opt/warehouse/lib/python3.8/site-packages/pluggy/_callers.py", line 55, in _multicall
gen.send(outcome)
File "/opt/warehouse/lib/python3.8/site-packages/_pytest/helpconfig.py", line 100, in pytest_cmdline_parse
config: Config = outcome.get_result()
File "/opt/warehouse/lib/python3.8/site-packages/pluggy/_result.py", line 60, in get_result
raise ex[1].with_traceback(ex[2])
File "/opt/warehouse/lib/python3.8/site-packages/pluggy/_callers.py", line 39, in _multicall
res = hook_impl.function(*args)
File "/opt/warehouse/lib/python3.8/site-packages/_pytest/config/__init__.py", line 1003, in pytest_cmdline_parse
self.parse(args)
File "/opt/warehouse/lib/python3.8/site-packages/_pytest/config/__init__.py", line 1283, in parse
self._preparse(args, addopts=addopts)
File "/opt/warehouse/lib/python3.8/site-packages/_pytest/config/__init__.py", line 1191, in _preparse
self.hook.pytest_load_initial_conftests(
File "/opt/warehouse/lib/python3.8/site-packages/pluggy/_hooks.py", line 265, in __call__
return self._hookexec(self.name, self.get_hookimpls(), kwargs, firstresult)
File "/opt/warehouse/lib/python3.8/site-packages/pluggy/_manager.py", line 80, in _hookexec
return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
File "/opt/warehouse/lib/python3.8/site-packages/pluggy/_callers.py", line 60, in _multicall
return outcome.get_result()
File "/opt/warehouse/lib/python3.8/site-packages/pluggy/_result.py", line 60, in get_result
raise ex[1].with_traceback(ex[2])
File "/opt/warehouse/lib/python3.8/site-packages/pluggy/_callers.py", line 34, in _multicall
next(gen) # first yield
File "/opt/warehouse/lib/python3.8/site-packages/_pytest/warnings.py", line 136, in pytest_load_initial_conftests
with catch_warnings_for_item(
File "/usr/local/lib/python3.8/contextlib.py", line 113, in __enter__
return next(self.gen)
File "/opt/warehouse/lib/python3.8/site-packages/_pytest/warnings.py", line 52, in catch_warnings_for_item
apply_warning_filters(config_filters, cmdline_filters)
File "/opt/warehouse/lib/python3.8/site-packages/_pytest/config/__init__.py", line 1603, in apply_warning_filters
warnings.filterwarnings(*parse_warning_filter(arg, escape=False))
File "/opt/warehouse/lib/python3.8/site-packages/_pytest/config/__init__.py", line 1579, in parse_warning_filter
category: Type[Warning] = warnings._getcategory(category_) # type: ignore[attr-defined]
File "/usr/local/lib/python3.8/warnings.py", line 262, in _getcategory
raise _OptionError("invalid module name: %r" % (module,)) from None
warnings._OptionError: invalid module name: 'warehouse.packaging.services'
However the actual issue is that there is some ModuleNotFoundError happening that we need to fix:
$ python warehouse/packaging/services.py
Traceback (most recent call last):
File "warehouse/packaging/services.py", line 23, in <module>
from warehouse.packaging.interfaces import IDocsStorage, IFileStorage
File "/opt/warehouse/src/warehouse/packaging/__init__.py", line 17, in <module>
from warehouse.accounts.models import Email, User
File "/opt/warehouse/src/warehouse/accounts/__init__.py", line 28, in <module>
from warehouse.accounts.services import (
File "/opt/warehouse/src/warehouse/accounts/services.py", line 29, in <module>
import warehouse.utils.webauthn as webauthn
File "/opt/warehouse/src/warehouse/utils/webauthn.py", line 18, in <module>
from webauthn.webauthn import (
ModuleNotFoundError: No module named 'webauthn.webauthn'
Ideally, invoking pytest would raise the ModuleNotFoundError or something similar, instead of a unhelpful warnings._OptionError.
This could be done by attempting to import the class in question before calling this line:
pytest/src/_pytest/config/__init__.py
Line 1625 in c82bda2
This happens with this set of requirements, on Python 3.8 (but also other Python and pytest versions).