升级pytest会导致TypeError：＆＃39; NoneType＆＃39; object不可调用错误

Question

需要帮助升级pytest。在3.2.4的情况下工作，如果我转到3.3.x或3.4.x我会得到一个我不理解的错误，我甚至无法执行-h参数。不知道从哪里开始或为什么会这样。我的virtualenv可能是个问题？

fresh virtualenv

我确实尝试了一个全新的virtualenv，但是，我仍然得到同样的错误。恢复为3.2.4修复它。

工作：

$ pytest --version
This is pytest version 3.2.4, imported from /Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pytest.py

升级到3.3.x

$ pytest --version
This is pytest version 3.3.2, imported from /Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pytest.py

$ pytest --help
Traceback (most recent call last):
  File "/Users/me/.virtualenvs/hitcount/bin/pytest", line 11, in <module>
    sys.exit(main())
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/_pytest/config.py", line 59, in main
    return config.hook.pytest_cmdline_main(config=config)
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pluggy/__init__.py", line 617, in __call__
    return self._hookexec(self, self._nonwrappers + self._wrappers, kwargs)
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pluggy/__init__.py", line 222, in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pluggy/__init__.py", line 216, in <lambda>
    firstresult=hook.spec_opts.get('firstresult'),
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pluggy/callers.py", line 201, in _multicall
    return outcome.get_result()
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pluggy/callers.py", line 76, in get_result
    raise ex[1].with_traceback(ex[2])
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pluggy/callers.py", line 180, in _multicall
    res = hook_impl.function(*args)
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/_pytest/helpconfig.py", line 102, in pytest_cmdline_main
    config._do_configure()
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/_pytest/config.py", line 921, in _do_configure
    self.hook.pytest_configure.call_historic(kwargs=dict(config=self))
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pluggy/__init__.py", line 630, in call_historic
    proc(x)
TypeError: 'NoneType' object is not callable

源：

这适用于我维护的开源项目：https://github.com/thornomad/django-hitcount

Answer 1

您遇到的错误不是pytest中的错误，而是基于pluggy的插件库中的错误。该错误已在2个月前修复（see this commit），但不幸的是，pluggy（0.6.0）的当前最后版本不包含此修复程序。

因此，您有两种可能性：

取决于pluggy快照

这是侵入性最小的一个。 pytest不需要pluggy的严格版本，因此只需要开发版本直到下一个pluggy版本：

# tests/requirements.txt

coverage==4.5.1
flake8==2.5.4
mock==2.0.0
pytest==3.4.2
pytest-django==3.1.2
selenium==3.10.0
tox==2.9.1
# add some meaningful explanation here 
# so you don't forget why you need this particular snapshot of pluggy
git+https://github.com/pytest-dev/pluggy@dcde058f93a509b9c39409fca02100e43bb43485

发布下一个版本后，删除快照依赖项和bump：

pluggy>0.6.0

调整pytest_configure挂钩

调整你的pytest_configure挂钩，使其不返回任何内容：

def configure():
    from django.conf import settings

    settings.configure(
        ...

    return settings

def pytest_configure():
    configure()

请勿忘记拨打configure()而不是runtests.py中的pytest_configure()功能，您就可以了。但是，这只是一个临时解决方法，可以在pluggy>0.6.0发布后恢复。

Answer 2

通过将pytest升级到4.0.1，可以解决此问题。 pytest> 5.1的最新版本与python> 3.4不兼容。