Refs #8620.
If we allow any value to remove form fields then we get name clashes
with method names, media classes etc. There was a backwards
incompatibility introduced meaning ModelForm subclasses with declared
fields called media or clean would lose those fields.
Field removal is now only permitted by using the sentinel value None.
The docs have been slightly reworded to refer to removal of fields
rather than shadowing.
Thanks to gcbirzan for the report and initial patch, and several of the
core team for opinions.
Backport of 9fb0f5dddc from master
Made explicit lack of microsecond handling by built-in datetime form
fields. Used that explicitness to appropriately nix microsecond
values in bound fields. Thanks Claude Paroz for the review.
Backport of a5de0df58 from master.
ForeignKey or ManyToManyField attribute ``limit_choices_to`` can now
be a callable that returns either a ``Q`` object or a dict.
Thanks michael at actrix.gen.nz for the original suggestion.
Overriding the error messages now works for both unique fields, unique_together
and unique_for_date.
This patch changed the overriding logic to allow customizing NON_FIELD_ERRORS
since previously only fields' errors were customizable.
Refs #20199.
Thanks leahculver for the suggestion.
This is the result of Christopher Medrela's 2013 Summer of Code project.
Thanks also to Preston Holmes, Tim Graham, Anssi Kääriäinen, Florian
Apolloner, and Alex Gaynor for review notes along the way.
Also: Fixes#8579, fixes#3055, fixes#19844.
On Python 3 sorting Fields mixed with GenericForeignKeys doesn't work
as GenericForeignKey isn't a subclass of django.db.models.fields.Field.
Refs #21428.
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.
model_to_dict() (used when rendering forms) queries the database
to get the list of primary keys for ManyToMany fields. This is
unnecessary if the field queryset has been prefetched, all the
keys are already in memory and can be obtained with a simple
iteration.