Pytest: On startup: AttributeError: 'str' object has no attribute 'pattern'

[rubik]

Pytest fails on startup with the following traceback:

$ pytest
Traceback (most recent call last):
  File "/home/dev/.local/share/virtualenvs/backend/bin/pytest", line 5, in <module>
    from pytest import main
  File "/home/dev/.local/share/virtualenvs/backend/lib/python3.8/site-packages/pytest.py", line 7, in <module>
    from _pytest.assertion import register_assert_rewrite
  File "/home/dev/.local/share/virtualenvs/backend/lib/python3.8/site-packages/_pytest/assertion/__init__.py", line 12, in <module>
    from _pytest.assertion import rewrite
  File "/home/dev/.local/share/virtualenvs/backend/lib/python3.8/site-packages/_pytest/assertion/rewrite.py", line 23, in <module>
    from _pytest.assertion import util
  File "/home/dev/.local/share/virtualenvs/backend/lib/python3.8/site-packages/_pytest/assertion/util.py", line 10, in <module>
    import _pytest._code
  File "/home/dev/.local/share/virtualenvs/backend/lib/python3.8/site-packages/_pytest/_code/__init__.py", line 6, in <module>
    from .code import Code  # noqa
  File "/home/dev/.local/share/virtualenvs/backend/lib/python3.8/site-packages/_pytest/_code/code.py", line 14, in <module>
    import pluggy
  File "/home/dev/.local/share/virtualenvs/backend/lib/python3.8/site-packages/pluggy/__init__.py", line 16, in <module>
    from .manager import PluginManager, PluginValidationError
  File "/home/dev/.local/share/virtualenvs/backend/lib/python3.8/site-packages/pluggy/manager.py", line 6, in <module>
    import importlib_metadata
  File "/home/dev/.local/share/virtualenvs/backend/lib/python3.8/site-packages/importlib_metadata/__init__.py", line 478, in <module>
    __version__ = version(__name__)
  File "/home/dev/.local/share/virtualenvs/backend/lib/python3.8/site-packages/importlib_metadata/__init__.py", line 445, in version
    return distribution(package).version
  File "/home/dev/.local/share/virtualenvs/backend/lib/python3.8/site-packages/importlib_metadata/__init__.py", line 418, in distribution
    return Distribution.from_name(package)
  File "/home/dev/.local/share/virtualenvs/backend/lib/python3.8/site-packages/importlib_metadata/__init__.py", line 179, in from_name
    dists = resolver(name)
  File "<frozen importlib._bootstrap_external>", line 1382, in find_distributions
  File "/home/dev/.local/share/virtualenvs/backend/lib/python3.8/importlib/metadata.py", line 400, in find_distributions
    found = cls._search_paths(context.pattern, context.path)
AttributeError: 'str' object has no attribute 'pattern'

Python version: 3.8.1
Pytest version: 4.5.0
OS: Archlinux 5.4.3

Other packages:

atomicwrites==1.3.0
attrs==19.1.0
backports.functools-lru-cache==1.5
certifi==2019.6.16
chardet==3.0.4
contextlib2==0.5.5
coverage==4.5.4
docopt==0.6.2
future==0.17.1
idna==2.8
importlib-metadata==0.19
jmespath==0.9.4
more-itertools==7.2.0
paho-mqtt==1.3.1
pbr==5.4.2
pluggy==0.12.0
py==1.8.0
pyjwt==1.7.1
pykwalify==1.7.0
pytest-cov==2.7.1
pytest==4.5.0
python-box==3.4.2
python-dateutil==2.8.0
pyyaml==5.1.2
requests==2.22.0
six==1.12.0
stevedore==1.30.1
tavern==0.27.0
urllib3==1.25.3
wcwidth==0.1.7
zipp==0.5.2

[The-Compiler]

If you run /home/dev/.local/share/virtualenvs/backend/bin/python -c 'import importlib_metadata', does the same happen as well?

[The-Compiler]

Issues which look somewhat related:

• https://gitlab.com/python-devs/importlib_metadata/issues/86
• https://github.com/pytest-dev/pluggy/issues/222

So you might want to try upgrading your importlib-metadata and/or pluggy.

[rubik]

@The-Compiler Thanks, that clarifies the issue. But then I think Pytest should also update its requirements. It should not depend on a broken package.

[asottile]

@rubik it doesn't, in python3.8 we don't use importlib_metadata we use importlib.metadata

[asottile]

you're on a very old version of pytest which is probably why it's being pulled in erroneously

[rubik]

@asottile My bad, you are right. There was another package pinning it down. Thanks, for the help.