What is the best way to resolve Rails orphaned migrations?

Question

I have been switching between branches in a project and each of them have different migrations... This is the scenario:

$ rake db:migrate:status

<

Answer 1

If the migration files are truly missing (e.g. ran migration, forgot to roll back migration, then deleted migration file before commit), I was able to reproduce the missing migration as follows:

1. go back in git history to get a copy of the schema.rb file and save outside of git repo (git log; git checkout xxxxxx; cp schema.rb ~/schema_old.rb, git checkout master).
2. run a diff on the two files, and copy the migration commands into a migration file that matches the missing migration ID (diff schema.rb ~/schema_old.rb > migration_file.rb; vi migration_file.rb)
3. Check your migration status and rollback (rake db:migrate:status; rake db:rollback; rake db:migrate:status;)