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
29799	Allow registration and unregistration of lookups per field instances.	Simon Charette	AllenJonathan	"Under certain circumstances it might be useful to register or unregister model field lookups on a per instance basis instead of a per class basis.

For example, it could be useful to disable costly lookups such as `contains` and `icontains` on some large table model `CharField`s without defining them using a `CharField` subclass to prevent them from being used in production. Similarly you might want to register or override a specific lookup for a third party app model field that doesn't allow swapping.

This was initially mentioned in #16187 which introduced this new lookup registration system.

https://code.djangoproject.com/ticket/16187#comment:14

> Having the ability to hook a custom lookup to a given field instance would be really nice to have...

https://code.djangoproject.com/ticket/16187#comment:22

> Add a way to register lookups to fields (I think either instances or classes is wanted behaviour).

But not discussed afterwhile. I believe class based registration was chosen because it was easier to implement but I agree that being able to register custom lookups per field instance would be good feature addition."	New feature	closed	Database layer (models, ORM)	dev	Normal	fixed	GSoC	Can Sarıgöl Himanshu Balasamanta Simon Charette	Ready for checkin	1	0	0	0	0	0