They were deprecated in Django 1.2 but not all the supporting code was
removed in Django 1.4. Since the remaining code was unlikely to be
functional (pun intended) e.g. it would crash unless the loader
function had an is_usable attribute, this commit completes the removal
immediately instead of starting another deprecation path.

This ensures that enabling the cached loader doesn't change behavior.

(Before this commit, it did when the list contained unusable loaders.)

This provides the opportunity to move utility functions specific to the
Django Template Language outside of django.template.loader.

It didn't account for class-based template loaders.

They can be replaced with override_settings and that makes the
corresponding tests much more obvious.

This change has the nice side effect of removing code that ran at import
time and depended on the app registry at module level -- a notorious
cause of AppRegistryNotReady exceptions.

It didn't do anything, wasn't documented and wasn't used anywhere.

Since it isn't branded as a test utility any more and could be used for
other purposes than test code, that prefix no longer makes sense.

It wasn't used anywhere either.

Reformatted the code of base.Loader according to modern standards.

Turned the test template loader into a regular locmem.Loader -- but
didn't document it.

Added a normal deprecation path for BaseLoader which is a public API.

Added an accelerated deprecation path for TestTemplateLoader which is
a private API.

That commit contained a mistake that resulted in the use_cached_loader
option of override_with_test_loader being ignored. As a consequence some
configurations weren't exercised any more by the test suite.

Fixes a race condition in the documentation.

The example for django.contrib.admin.ModelAdmin.get_form was modifying self.exclude. However, since ModelAdmin instances are global and have no thread- or request-locality, this is not safe for concurrent requests. This updated documentation demonstrates a safe method to override admin forms on a per-request basis.

Fixed #23585 - Corrected internal comment.

Fixed #23690 - fixed examples of manual rendering of form fields

The example for django.contrib.admin.ModelAdmin.get_form modifies
self.exclude. However, since ModelAdmin instances are global and have no
thread- or request-locality, this is not safe for concurrent
requests.[1] This updated documentation demonstrates a safe method to
override admin forms on a per-request basis.

[1] https://groups.google.com/forum/#!topic/django-users/AmoUDtEefyA

Fixed #23808 -- Documented that migrations table is created when using runserver without migrating first.

Fixes #23837: Replace list with deque in migration-planner for improved performance.

Thanks Reinout van Rees for the review.

fixed #23834 -- added test and fix to check for default null on ArrayField

This commit broke the tests on Python 3.

This reverts commit 13d613f8.

Fixed #23827 -- TZ behavior in Storage API ref doc

Use topological sort for migration operation dependency resolution

rather than an ad-hoc algorithm