Weird behavior when using a subdomain and doing a request from another host on tests

[stsewd]

This is more an issue report that a PR. I'm doing this because I think is easier to show what's happening and get help since I'm not sure why is this happening :/.

When @override_settings(USE_SUBDOMAIN=True) and self.client.get('/projects/sub_alias/', HTTP_HOST='pip.readthedocs.org') is used, the reverse function fails (throw an exception). After doing the same request without the HTTP_HOST header, everything is back to normal.

Note that this behavior isn't just happening inside this test, but on all tests after this one (see #3913 (comment)). You can tests this, by adding a tests case that uses the reverse function after the ResolverBase

class TestClass(TestCase):

    def test_other_test(self):
        reverse('project-sync-versions', args=[1])

I think maybe this is related to the custom resolver that keeps a state between each test case.

[stsewd]

I just found the problem.

When the request is made inside that test, django overrides the url_conf (readthedocs.core.urls.subdomain) for the current thread! https://docs.djangoproject.com/en/1.9/_modules/django/core/urlresolvers/ (set_urlconf). So, all tests are running in that thread with that configuration, till the value get's override (to readthedocs.urls) doing another request without the HTTP_HOST header.

So, is this a bug on django or on the rtd code? This can be fixed by calling a method on the teardown method, but still, is kind of hacky.

[stsewd]

The commit 314f631 should have failed on travis... You can check the tests locally, commenting out the teardown part and running tox -e py36 readthedocs/rtd_tests/tests/test_subprojects.py.

[stsewd]

Closing this PR and opening a different one having the relevant changes only