Flake8 build error in Travis

Flake8 checks are currently failing with the following for all files:

.tox/flake8/lib/python3.8/site-packages/pluggy/hooks.py:286: in __call__
    return self._hookexec(self, self.get_hookimpls(), kwargs)
.tox/flake8/lib/python3.8/site-packages/pluggy/manager.py:93: in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
.tox/flake8/lib/python3.8/site-packages/pluggy/manager.py:84: in <lambda>
    self._inner_hookexec = lambda hook, methods, kwargs: hook.multicall(
.tox/flake8/lib/python3.8/site-packages/_pytest/runner.py:134: in pytest_runtest_call
    item.runtest()
.tox/flake8/lib/python3.8/site-packages/pytest_flake8.py:119: in runtest
    found_errors, out, err = call(
.tox/flake8/lib/python3.8/site-packages/py/_io/capture.py:150: in call
    res = func(*args, **kwargs)
.tox/flake8/lib/python3.8/site-packages/pytest_flake8.py:191: in check_file
    app.parse_preliminary_options_and_args(args)
E   AttributeError: 'Application' object has no attribute 'parse_preliminary_options_and_args'

Failed builds:

• https://travis-ci.org/github/scrapy/scrapy/jobs/686060612
• https://travis-ci.org/github/scrapy/scrapy/jobs/685973155

I suspect there might have been some change in a recent release of pytest-flake8, and pinning the version would solve the problem.

[noviluni]

It seems fixed 🎉

Passing PR: https://github.com/scrapy/scrapy/pull/4572

[elacuesta]

Yup, I was evaluating if we should pin flake8 or wait for an upstream fix to arrive. Nice work on the fix!