[WIP] fixes #3664

[avirlrma]

fixes #3664.
for now, I was able to get an exception when we apply a fixture to an already marked function. But the output of the same is not very pretty.

(ok-SmhP-Aw1) xx@dell:~/ok/pytest$ pytest ../test_fix_mark.py 
======================================================================================= test session starts ========================================================================================
platform linux -- Python 3.6.5, pytest-3.8.2.dev38+g25fe3706, py-1.6.0, pluggy-0.7.1
rootdir: /home/xx/ok, inifile:
collected 1 item                                                                                                                                                                                   

../test_fix_mark.py E                                                                                                                                                                        [100%]

============================================================================================== ERRORS ==============================================================================================
_____________________________________________________________________________________ ERROR at setup of test_a _____________________________________________________________________________________

self = <CallInfo when='setup' exception: i did it!>, func = <function call_runtest_hook.<locals>.<lambda> at 0x7f7327859158>, when = 'setup', treat_keyboard_interrupt_as_exception = False

    def __init__(self, func, when, treat_keyboard_interrupt_as_exception=False):
        #: context of invocation: one of "setup", "call",
        #: "teardown", "memocollect"
        self.when = when
        self.start = time()
        try:
>           self.result = func()

src/_pytest/runner.py:201: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
src/_pytest/runner.py:183: in <lambda>
    lambda: ihook(item=item, **kwds),
../../.local/share/virtualenvs/ok-SmhP-Aw1/lib/python3.6/site-packages/pluggy/hooks.py:258: in __call__
    return self._hookexec(self, self._nonwrappers + self._wrappers, kwargs)
../../.local/share/virtualenvs/ok-SmhP-Aw1/lib/python3.6/site-packages/pluggy/manager.py:67: in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
../../.local/share/virtualenvs/ok-SmhP-Aw1/lib/python3.6/site-packages/pluggy/manager.py:61: in <lambda>
    firstresult=hook.spec_opts.get('firstresult'),
src/_pytest/runner.py:104: in pytest_runtest_setup
    item.session._setupstate.prepare(item)
src/_pytest/runner.py:370: in prepare
    col.setup()
src/_pytest/python.py:1463: in setup
    fixtures.fillfixtures(self)
src/_pytest/fixtures.py:294: in fillfixtures
    request._fillfixtures()
src/_pytest/fixtures.py:467: in _fillfixtures
    item.funcargs[argname] = self.getfixturevalue(argname)
src/_pytest/fixtures.py:511: in getfixturevalue
    return self._get_active_fixturedef(argname).cached_result[0]
src/_pytest/fixtures.py:534: in _get_active_fixturedef
    self._compute_fixture_value(fixturedef)
src/_pytest/fixtures.py:620: in _compute_fixture_value
    fixturedef.execute(request=subrequest)
src/_pytest/fixtures.py:913: in execute
    return hook.pytest_fixture_setup(fixturedef=self, request=request)
../../.local/share/virtualenvs/ok-SmhP-Aw1/lib/python3.6/site-packages/pluggy/hooks.py:258: in __call__
    return self._hookexec(self, self._nonwrappers + self._wrappers, kwargs)
../../.local/share/virtualenvs/ok-SmhP-Aw1/lib/python3.6/site-packages/pluggy/manager.py:67: in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
../../.local/share/virtualenvs/ok-SmhP-Aw1/lib/python3.6/site-packages/pluggy/manager.py:61: in <lambda>
    firstresult=hook.spec_opts.get('firstresult'),
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

fixturedef = <FixtureDef name='user_tom' scope='function' baseid='test_fix_mark.py' >, request = <SubRequest 'user_tom' for <Function 'test_a'>>

    def pytest_fixture_setup(fixturedef, request):
        """ Execution of fixture setup. """
        kwargs = {}
        for argname in fixturedef.argnames:
            fixdef = request._get_active_fixturedef(argname)
            result, arg_cache_key, exc = fixdef.cached_result
            request._check_scope(argname, request.scope, fixdef.scope)
            kwargs[argname] = result
    
        fixturefunc = resolve_fixture_function(fixturedef, request)
        if hasattr(fixturefunc,'pytestmark'):
>           raise Exception('i did it!')
E           Exception: i did it!

src/_pytest/fixtures.py:954: Exception

I will try to make this right.

[nicoddemus]

Use fail(msg, pytrace=False) instead. 😁

Also this should go into features, as it might break functional (but incorrect) test suites.

[avirlrma]

oh thanks @nicoddemus.
so the course of action will be:

• move to features.
• correct the error invokation.
• write tests for this.
• then work on the other half
  right?

[nicoddemus]

Correct. Thanks for tackling this! 👍