id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
27944	Have meta.get_field('pk') return the primary key field directly	Josh Schneier	Josh Schneier	"Follow up ticket discussion on this topic: https://github.com/django/django/pull/8148

While fixing #27897, which is caused by calling `.get_field('pk')`, I ran across the fact that we are now checking `== 'pk'` before calling `.get_field` in several places. My proposal is to simply handle this special case inside of `get_field` directly.

I have a patch but there is a single test regression on [https://github.com/django/django/blob/master/django/db/models/fields/__init__.py#L232-L239| this system check]. My idea was to change the message and `obj` to `self.model` but I'm not sure what the backwards compatibility guarantees are for the message.

Regardless I think we should do this because it will prevent a whole class of bugs in the future and `'pk'` is already special cased everywhere. "	Cleanup/optimization	closed	Database layer (models, ORM)	dev	Normal	wontfix			Someday/Maybe	1	0	0	0	0	0