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
19969	More useful error message when defining ForeignKey with invalid first argument	Jonas Obrist	nobody	"When you create a ForeignKey with an invalid first argument (for example None), you get an error message:

`AssertionError: ForeignKey(None) is invalid. First parameter to ForeignKey must be either a model, a model name, or the string 'self'`

What this does not tell you is what model in what app and what field this error occurs.

I therefore propose that this check is moved to contribute_to_class where we have all the information.

(For the record if anyone stumbles up on this, you can use `--traceback` which will give you this information)"	Cleanup/optimization	closed	Database layer (models, ORM)	1.5	Normal	duplicate			Unreviewed	0	0	0	0	0	0