Thanks Simon Charette for the review.

This should prevent managers methods from returning content type instances
registered to foreign apps now that these managers are also attached to models
created during migration phases.

Thanks Tim for the review.

Refs #23822.

Made SessionTestsMixin backend agnostic and removed code obsoleted by the test
discovery refactor.

Thanks Markus Holtermann for review.

Thanks Simon Charette for help.

contrib.auth.views.login() has a new parameter `redirect_authenticated_user`
to automatically redirect authenticated users visiting the login page.

Thanks to dmathieu and Alex Buchanan for the original code and to Carl Meyer
for the help and review.

Thanks Tim Graham for the review.

Thanks Tim Graham for the review.

Removed in Django 1.7 (4f6be9a0).

New Storage.get_{accessed,created,modified}_time() methods convert the
naive time from now-deprecated {accessed,created_modified}_time()
methods into aware objects in UTC if USE_TZ=True.

Refs #25925. Thanks Jeroen Pulles for the report.

When running collectstatic with a hashing static file storage backend,
URLs referencing other files were normalized with posixpath.normpath.
This could corrupt URLs: for example 'a.css#b/../c' became just 'c'.

Normalization seems to be an artifact of the historical implementation.
It contained a home-grown implementation of posixpath.join which relied
on counting occurrences of .. and /, so multiple / had to be collapsed.

The new implementation introduced in the previous commit doesn't suffer
from this issue. So it seems safe to remove the normalization.

There was a test for this normalization behavior but I don't think it's
a good test. Django shouldn't modify CSS that way. If a developer has
rendundant /s, it's mostly an aesthetic issue and it isn't Django's job
to fix it. Conversely, if the user wants a series of /s, perhaps in the
URL fragment, Django shouldn't destroy it.

Refs #26249.

collectstatic crashed when:

* a hashing static file storage backend was used
* a static file referenced another static file located directly in
  STATIC_ROOT (not a subdirectory) with an absolute URL (which must
  start with STATIC_URL, which cannot be empty)

It seems to me that the current code reimplements relative path joining
and doesn't handle edge cases correctly. I suspect it assumes that
STATIC_URL is of the form r'/[^/]+/'.

Throwing out that code in favor of the posixpath module makes the logic
easier to follow. Handling absolute paths correctly also becomes easier.

Thanks Tim Graham for the review.

Refs #26190.

Thanks Tim Graham for the review.