5.1 fails for python 3.8

[thirtytwobits]

Our project's python3.8 tox run started to fail when using pytest 5.1 or greater.

nunavut tox -e py38-test

py38-test run-test: commands[1] | coverage run --parallel-mode --rcfile=/repo/setup.cfg -m pytest --basetemp=/repo/.tox/py38-test/tmp -p no:cacheprovider --rootdir=/repo /repo/test
Traceback (most recent call last):
  File "/repo/.tox/py38-test/lib/python3.8/site-packages/pytest.py", line 7, in <module>
    from _pytest.config import cmdline
  File "/repo/.tox/py38-test/lib/python3.8/site-packages/_pytest/config/__init__.py", line 30, in <module>
    from _pytest.compat import importlib_metadata
  File "/repo/.tox/py38-test/lib/python3.8/site-packages/_pytest/compat.py", line 30, in <module>
    from importlib import metadata as importlib_metadata  # noqa
ImportError: cannot import name 'metadata' from 'importlib' (/repo/.tox/py38-test/lib/python3.8/importlib/__init__.py)
Coverage.py warning: Module nunavut was never imported. (module-not-imported)
Coverage.py warning: No data was collected. (no-data-collected)
ERROR: InvocationError for command /repo/.tox/py38-test/bin/coverage run --parallel-mode --rcfile=/repo/setup.cfg -m pytest --basetemp=/repo/.tox/py38-test/tmp -p no:cacheprovider --rootdir=/repo test (exited with code 1)

[nicoddemus]

Hi @thirtytwobits,

While we still have a few failing tests under our test suite on py38 (which we should try to fix soon), the problem you are describing should not exist, importlib is builtin in Python 3.8:

 λ py -3.8
Python 3.8.0b4 (tags/v3.8.0b4:d93605d, Aug 29 2019, 23:21:28) [MSC v.1916 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> from importlib import metadata as importlib_metadata
>>>

Which Python 3.8 version are you using? Also, can you provide the output of:

py -3.8 -c "import importlib.metadata;print(importlib.metadata)"

[thirtytwobits]

Ah. I see what's going on now. This is a rolling break between pytest and python 3.8. 3.8 is not an official release so this is completely reasonable. I've rebuilt our docker container (https://cloud.docker.com/u/uavcan/repository/docker/uavcan/toxic) and this seems to work now. Sorry for the noise.

[Madoshakalaka]

I also get this error in a tox build:

Traceback (most recent call last):
  File "/home/matt/PycharmProjects/pipenv-setup/.tox/py38/bin/pytest", line 5, in <module>
    from pytest import main
  File "/home/matt/PycharmProjects/pipenv-setup/.tox/py38/lib/python3.8/site-packages/pytest.py", line 6, in <module>
    from _pytest.assertion import register_assert_rewrite
  File "/home/matt/PycharmProjects/pipenv-setup/.tox/py38/lib/python3.8/site-packages/_pytest/assertion/__init__.py", line 7, in <module>
    from _pytest.assertion import rewrite
  File "/home/matt/PycharmProjects/pipenv-setup/.tox/py38/lib/python3.8/site-packages/_pytest/assertion/rewrite.py", line 26, in <module>
    from _pytest.assertion import util
  File "/home/matt/PycharmProjects/pipenv-setup/.tox/py38/lib/python3.8/site-packages/_pytest/assertion/util.py", line 8, in <module>
    import _pytest._code
  File "/home/matt/PycharmProjects/pipenv-setup/.tox/py38/lib/python3.8/site-packages/_pytest/_code/__init__.py", line 2, in <module>
    from .code import Code  # noqa
  File "/home/matt/PycharmProjects/pipenv-setup/.tox/py38/lib/python3.8/site-packages/_pytest/_code/code.py", line 23, in <module>
    import pluggy
  File "/home/matt/PycharmProjects/pipenv-setup/.tox/py38/lib/python3.8/site-packages/pluggy/__init__.py", line 16, in <module>
    from .manager import PluginManager, PluginValidationError
  File "/home/matt/PycharmProjects/pipenv-setup/.tox/py38/lib/python3.8/site-packages/pluggy/manager.py", line 9, in <module>
    from importlib import metadata as importlib_metadata
ImportError: cannot import name 'metadata' from 'importlib' (/home/matt/PycharmProjects/pipenv-setup/.tox/py38/lib/python3.8/importlib/__init__.py)

[xsteadfastx]

i also get this error while testing with python 3.8.0 and pytest 5.3.0.