LiveServerTestCase.setUpClass() doesn't clean up fully on failure

[Chris Jerdonek]

While working on #32417, I noticed in this comment that LiveServerTestCase.setUpClass() doesn't clean up all the way if setUpClass() errors out.

Specifically, LiveServerTestCase.setUpClass() ​looks like this:

@classmethod
def setUpClass(cls):
    super().setUpClass()
    ...
    cls._live_server_modified_settings = modify_settings(
        ALLOWED_HOSTS={'append': cls.allowed_host},
    )
    cls._live_server_modified_settings.enable()
    ...
    if cls.server_thread.error:
        # Clean up behind ourselves, since tearDownClass won't get called in
        # case of errors.
        cls._tearDownClassInternal()
        raise cls.server_thread.error

But _tearDownClassInternal() ​doesn't undo the call to cls._live_server_modified_settings.enable().

I will post a PR shortly.

[Florian Apolloner]

The cleanup precedes the commit that modified the settings by three years (​https://github.com/django/django/commit/17e661641ddaf8266e7430d83cfb2039abc55df7 & ​https://github.com/django/django/commit/73a610d2a81bc3bf2d3834786b2458bc85953ed0) so it is more than likely that this was just an oversight at the time. I'll give the PR a review in a second.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 694deff8:

Fixed #32437 -- Fixed cleaning up ALLOWED_HOSTS in LiveServerTestCase on setUpClass() failure.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 65a62094:

[3.2.x] Fixed #32437 -- Fixed cleaning up ALLOWED_HOSTS in LiveServerTestCase on setUpClass() failure.

Backport of 694deff82f86e025561dfa724425f67e2ff7cbb7 from master