[Pytest-commit] Issue #704: Needs to handle VersionConflict in consider_setuptools_entrypoints (pytest-dev/pytest)

[Daniel Hahler]

New issue 704: Needs to handle VersionConflict in consider_setuptools_entrypoints
https://bitbucket.org/pytest-dev/pytest/issue/704/needs-to-handle-versionconflict-in

Daniel Hahler:

I was getting the following error, caused by the testmon plugin, which
requires pytest<2.7:

    …/pyenv/project2/lib/python2.7/site-packages/_pytest/config.py in _preparse(self, args, addopts)
        711         self._checkversion()
        712         self.pluginmanager.consider_preparse(args)
    --> 713         self.pluginmanager.consider_setuptools_entrypoints()
        714         self.pluginmanager.consider_env()
        715         self.known_args_namespace = ns = self._parser.parse_known_args(args)

    …/pyenv/project2/lib/python2.7/site-packages/_pytest/core.py in consider_setuptools_entrypoints(self)
        276                 continue
        277             try:
    --> 278                 plugin = ep.load()
        279             except DistributionNotFound:
        280                 continue

    …/pyenv/project2/lib/python2.7/site-packages/pkg_resources/__init__.py in load(self, require, *args, **kwargs)
       2318             )
       2319         if require:
    -> 2320             self.require(*args, **kwargs)
       2321         return self.resolve()
       2322 

    …/pyenv/project2/lib/python2.7/site-packages/pkg_resources/__init__.py in require(self, env, installer)
       2335             raise UnknownExtra("Can't require() without a distribution", self)
       2336         reqs = self.dist.requires(self.extras)
    -> 2337         items = working_set.resolve(reqs, env, installer)
       2338         list(map(working_set.add, items))
       2339 

    …/pyenv/project2/lib/python2.7/site-packages/pkg_resources/__init__.py in resolve(self, requirements, env, installer, replace_conflicting)
        812                 dependent_req = required_by[req]
        813                 import ipdb; ipdb.set_trace()  # noqa
    --> 814                 raise VersionConflict(dist, req).with_context(dependent_req)
        815 
        816             # push the new requirements onto the stack

    VersionConflict: (pytest 2.7.0 (…/pyenv/project2/lib/python2.7/site-packages), Requirement.parse('pytest<2.7'))


    ipdb> args
    self = <pkg_resources.WorkingSet object at 0x7f3ec2a55cd0>
    requirements = [Requirement.parse('pathtools>=0.1.1'), Requirement.parse('argh>=0.24.1'), Requirement.parse('PyYAML>=3.10'), Requirement.parse('execnet>=1.1.dev1'), Requ
    irement.parse('pytest>=2.2')]                                                                                                                                            env = None
    installer = None
    replace_conflicting = False


`ep` is `EntryPoint.parse('testmon = testmon.plugin')`.

It would be nice if there was a warning in such a case and the plugin was
skipped.

A warning might be useful with the current handling of `DistributionNotFound`,
too.