Migrations: Removing a field with foreign key constraint fails

[László Károlyi]

Hey,

I have a model that has a foreign key to another model. Let's say I change my mind and want the relation the other way around (the another model having a foreign key to my model), and so I modify the models accordingly, removing the foreign key of my model.

This creates a migration with a migrations.RemoveField on the model, which is just right. But when running this migration on MySQL, I get an error saying

django.db.utils.OperationalError: (1553, "Cannot drop index 'base_comment_f6be1d8d': needed in a foreign key constraint")

and the migration fails.

Shouldn't the migrations.RemoveField drop that constraint automatically?

This happens using python 3, might have to do something with #24390.