It contained models, forms and admin objects causing undesirable
import side effects. Refs #16368.

Thanks to Ramiro, Carl and Loïc for the review.

The GenericRelation refactoring removed GenericRelations from
model._meta.many_to_many. This had the side effect of disallowing
editable GenericRelations in ModelForms. Editable GenericRelations
aren't officially supported, but if we don't fix this we don't offer any
upgrade path for those who used the ability to set editable=True
in GenericRelation subclass.

Thanks to Trac alias joshcartme for the report and stephencmd and Loic
for working on this issue.

Signed-off-by: Jason Myers <jason@jasonamyers.com>

The patch for #19385 caused a regression in certain generic relations
.exclude() filters if a subquery was needed. The fix contains a
refactoring to how Query.split_exclude() and Query.trim_start()
interact.

Thanks to Trac alias nferrari for the report.

When a GenericRelation was defined on abstract model, queries on childs
of the abstract model didn't work. The problem was in the way fields and
in particular field.rel was copied from models to their children.

The regression was likely caused by #19385. Thanks to Gavin Wahl for
spotting the regression.

Also, according to the comments on the ticket and its duplicates, added
tests execising saving an instance of a model with a GFK to:

* An unsaved object -- This actually doesn't generate the same failure
  but another ORM-level exception. The test verifies it's the case.

* An instance of a model with a __nonzero__() method thant returns False
  for it. This doesn't fail because that code path isn't executed.

* An instance of a model with a CharField PK and an empty value for it.
  This doesn't fail.

Thanks adurdin for the report and patch. Fixes #11387.

* Renamed the __unicode__ methods
* Applied the python_2_unicode_compatible decorator
* Removed the StrAndUnicode mix-in that is superseded by
  python_2_unicode_compatible
* Kept the __unicode__ methods in classes that specifically
  test it under Python 2

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16981 bcc190cf-cafb-0310-a4f2-bffc1f526a37

Fixed #11535: Corrected SQL generated for queries involving generic relations and ORed Q objects. Thanks to brianglass for report, tobias for fix and test, and Alex for review.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@12405 bcc190cf-cafb-0310-a4f2-bffc1f526a37

Fixed #12721: Ensured objects with generic relations that use non-integer object ID fields can be deleted on PostgreSQL. Thanks much carljm for patch and Russ for review.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@12353 bcc190cf-cafb-0310-a4f2-bffc1f526a37

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12276 bcc190cf-cafb-0310-a4f2-bffc1f526a37

Fixed #9546: GenericRelations inherited from base models no longer query using the wrong content type.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@10373 bcc190cf-cafb-0310-a4f2-bffc1f526a37