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
29911	Standardize delete_cached_value API on model Fields	Taylor H	nobody	"I created a custom Django model field that is expensive to calculate and I store a cached value on the model. I am not able to clear the cache when some uses the refresh_from_db() method though, since there is no standard API to hook into it. It appears that there is a custom behavior for ForeignKey that calls the delete_cached_value function, if it detects it's a ForeignKey

https://github.com/django/django/blob/master/django/db/models/base.py#L569

It would be great to allow any custom Field to implement `delete_cached_value` and have it called inside refresh_from_db. What are your thoughts? I would be happy to submit a PR if this seems reasonable"	New feature	new	Database layer (models, ORM)	2.1	Normal				Unreviewed	0	0	0	0	0	0