Adding parent _ptr field causes migration problems if not last (?) #2
Description
Some attempts to extract another parent from a model that has already been broken down showed this odd pattern: If the new parent-_ptr field was not add as the last parent-_ptr field, the migration auto-detector keeps thinking the model's primary key needs to be changed to a relation.
This still requires investigation -- to see if it was diagnosed correctly, and to see if it can be fixed or needs to be documented as a limitation.