unknown hook 'pytest_namespace'

[nim65s]

Issue description

running make check on master on ArchLinux raises the following exception:

================================================= test session starts =================================================
platform linux -- Python 3.7.2, pytest-4.1.1, py-1.7.0, pluggy-0.8.1
rootdir: /pybind11/tests, inifile: pytest.ini
collecting 131 items / 13 errors                                                                                      INTERNALERROR> Traceback (most recent call last):
INTERNALERROR>   File "/usr/lib/python3.7/site-packages/_pytest/main.py", line 203, in wrap_session
INTERNALERROR>     session.exitstatus = doit(config, session) or 0
INTERNALERROR>   File "/usr/lib/python3.7/site-packages/_pytest/main.py", line 242, in _main
INTERNALERROR>     config.hook.pytest_collection(session=session)
INTERNALERROR>   File "/usr/lib/python3.7/site-packages/pluggy/hooks.py", line 284, in __call__
INTERNALERROR>     return self._hookexec(self, self.get_hookimpls(), kwargs)
INTERNALERROR>   File "/usr/lib/python3.7/site-packages/pluggy/manager.py", line 68, in _hookexec
INTERNALERROR>     return self._inner_hookexec(hook, methods, kwargs)
INTERNALERROR>   File "/usr/lib/python3.7/site-packages/pluggy/manager.py", line 62, in <lambda>
INTERNALERROR>     firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
INTERNALERROR>   File "/usr/lib/python3.7/site-packages/pluggy/callers.py", line 208, in _multicall
INTERNALERROR>     return outcome.get_result()
INTERNALERROR>   File "/usr/lib/python3.7/site-packages/pluggy/callers.py", line 80, in get_result
INTERNALERROR>     raise ex[1].with_traceback(ex[2])
INTERNALERROR>   File "/usr/lib/python3.7/site-packages/pluggy/callers.py", line 187, in _multicall
INTERNALERROR>     res = hook_impl.function(*args)
INTERNALERROR>   File "/usr/lib/python3.7/site-packages/_pytest/main.py", line 252, in pytest_collection
INTERNALERROR>     return session.perform_collect()
INTERNALERROR>   File "/usr/lib/python3.7/site-packages/_pytest/main.py", line 466, in perform_collect
INTERNALERROR>     self.config.pluginmanager.check_pending()
INTERNALERROR>   File "/usr/lib/python3.7/site-packages/pluggy/manager.py", line 251, in check_pending
INTERNALERROR>     % (name, hookimpl.plugin),
INTERNALERROR> pluggy.manager.PluginValidationError: unknown hook 'pytest_namespace' in plugin <module 'conftest' from '/pybind11/tests/conftest.py'>

============================================== 14 error in 4.79 seconds ===============================================

Reproducible example code

Here is a Dockerfile to reproduce it:

FROM base/archlinux

RUN pacman -Syu --noconfirm base-devel git cmake python-pytest
RUN git clone https://github.com/pybind/pybind11.git

RUN mkdir /build
WORKDIR /build

RUN cmake /pybind11
RUN make check -j 4

[bstaletic]

Yes, the latest pytest broke pybind. That's why the builds are broken on master. Unfortunately I have no idea what is going on or how to fix it.

[nim65s]

I see, this comes from pytest-dev/pytest#4421

[Feng137]

Try to install a earlier pytest. I have change the pytest version from 5.2.2 to 4.6.6, and it works.

[VidyaCK]

@azrael0fog, I installed latest version. But, It couldn't resolve my issue.

[turkus]

Please take a look at:
https://stackoverflow.com/a/61048783/6734406

[akozyreva]

Please take a look at:
https://stackoverflow.com/a/61048783/6734406

Is it somewhere documented??

[turkus]

@akozyreva
Yes, of course, there is a link under the phrase changelog in the answer on stackoverflow.
Sorry for the new issue, miss click.