Django migrations and branching

I got myself in to django migration hell this week. Here's how.

Working on my main branch, then switched to a feature branch created by a co-worker (we'll call him Barnaby). The feature branch had some model changes, and some migrations. I ran those migrations, and viewed the feature branch.

Then I switched back to my main branch. I got errors because the database no longer matched my models. I tried (without thinking it through) to migrate backwards. This didn't work, becuase the migrations that had gotten me in to this state were no longer present. I then made the mistake of manually updating my database to its pre-migration state.

This put me in a situation where when I tried to re-run the migration, after merging in Barnaby's code, it didn't want to run, because the migration was recorded in the django_migrations table. I tried deleting the migration entry and got myself in to more trouble, with this error:

django.db.utils.ProgrammingError: relation "signage_scheduleentry_0dee419f" already exists

I don't know how deep this rabbit hole will go, so am just restoring my development database from a backup.