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
37049	Changing a m2m through= from one custom model to another is no-op'd instead of raising an error	Clifford Gama	Clifford Gama	"Bug in b25aee3b7bef07dd07bed2209efcdf1a8146112c of ticket #22476.

The check to make changes to field options like `blank=True` on m2m's with a custom through model no-ops is currently only checking that both through models were non-auto-created [https://github.com/django/django/blob/1b0d46f715849de53563aaf6912b4ded7d61641d/django/db/backends/base/schema.py#L882-L893 source], rather than verifying they are the same model. This means any two custom through models would satisfy the check and short-circuit.

See regression test in [https://github.com/django/django/pull/21131 PR] for how to reproduce."	Bug	assigned	Migrations	dev	Normal		migrations, ManyToManyField, through		Unreviewed	1	0	0	0	0	0