fix: move 'import getpass' statement to try-clause

[paulmueller]

This fixes an issue that I have in combination with coverage and the tmp_path fixture:

I am not sure what exactly causes this. Maybe coverage hides some environment variables. I also find it strange that It is not possible to import a module from the standard library. But in any case, I think this fix is light-weight and should not cause any trouble in the future.

The error message goes like this:

==================================== ERRORS ====================================
_______________ ERROR at setup of test_store_and_get_certificate _______________

cls = <class '_pytest.runner.CallInfo'>
func = <function call_runtest_hook.<locals>.<lambda> at 0x7f8bd786f7f0>
when = 'setup'
reraise = (<class '_pytest.outcomes.Exit'>, <class 'KeyboardInterrupt'>)

    @classmethod
    def from_call(
        cls,
        func: "Callable[[], TResult]",
        when: "Literal['collect', 'setup', 'call', 'teardown']",
        reraise: Optional[
            Union[Type[BaseException], Tuple[Type[BaseException], ...]]
        ] = None,
    ) -> "CallInfo[TResult]":
        """Call func, wrapping the result in a CallInfo.
    
        :param func:
            The function to call. Called without arguments.
        :param when:
            The phase in which the function is called.
        :param reraise:
            Exception or exceptions that shall propagate if raised by the
            function, instead of being wrapped in the CallInfo.
        """
        excinfo = None
        start = timing.time()
        precise_start = timing.perf_counter()
        try:
>           result: Optional[TResult] = func()

/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/runner.py:338: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/runner.py:259: in <lambda>
    lambda: ihook(item=item, **kwds), when=when, reraise=reraise
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/pluggy/_hooks.py:265: in __call__
    return self._hookexec(self.name, self.get_hookimpls(), kwargs, firstresult)
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/pluggy/_manager.py:80: in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/runner.py:154: in pytest_runtest_setup
    item.session._setupstate.setup(item)
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/runner.py:494: in setup
    raise exc
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/runner.py:491: in setup
    col.setup()
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/python.py:1764: in setup
    self._request._fillfixtures()
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/fixtures.py:541: in _fillfixtures
    item.funcargs[argname] = self.getfixturevalue(argname)
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/fixtures.py:554: in getfixturevalue
    fixturedef = self._get_active_fixturedef(argname)
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/fixtures.py:573: in _get_active_fixturedef
    self._compute_fixture_value(fixturedef)
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/fixtures.py:659: in _compute_fixture_value
    fixturedef.execute(request=subrequest)
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/fixtures.py:1057: in execute
    result = ihook.pytest_fixture_setup(fixturedef=self, request=request)
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/pluggy/_hooks.py:265: in __call__
    return self._hookexec(self.name, self.get_hookimpls(), kwargs, firstresult)
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/pluggy/_manager.py:80: in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/fixtures.py:1111: in pytest_fixture_setup
    result = call_fixture_func(fixturefunc, request, kwargs)
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/fixtures.py:890: in call_fixture_func
    fixture_result = fixturefunc(**kwargs)
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/tmpdir.py:211: in tmp_path
    return _mk_tmp(request, tmp_path_factory)
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/tmpdir.py:194: in _mk_tmp
    return factory.mktemp(name, numbered=True)
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/tmpdir.py:93: in mktemp
    basename = self._ensure_relative_to_basetemp(basename)
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/tmpdir.py:74: in _ensure_relative_to_basetemp
    if (self.getbasetemp() / basename).resolve().parent != self.getbasetemp():
/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/tmpdir.py:116: in getbasetemp
    user = get_user() or "unknown"
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

    def get_user() -> Optional[str]:
        """Return the current user name, or None if getuser() does not work
        in the current environment (see #1010)."""
>       import getpass
E       ModuleNotFoundError: No module named 'getpass'

/opt/hostedtoolcache/Python/3.10.4/x64/lib/python3.10/site-packages/_pytest/tmpdir.py:161: ModuleNotFoundError

[paulmueller]

Please squash-and-merge.
See also #1013.

[Zac-HD]

Hi Paul - thanks so much for reporting and fixing this bizarre bug! I also have no idea why import getpass can fail, but since it clearly can in some cases this looks like the correct fix to me.

One small comment below about the changelog entry, and then I'll be happy to merge this 😁

[Zac-HD]

Because the changelog is part of our user-facing documentation, we should describe this in terms of user-visible symptoms which are visible from the public API. In this case, I think that means something like:

Fix a bizarre (and fortunately rare) bug where the `temp_path` fixture could raise
an internal error while attempting to get the current user's username.

[paulmueller]

Thanks, done!

[Zac-HD]

Woohoo! Thanks again Paul 🥰