Update-Database tries to do an automatic migration even with automatic migrations disabled

Question

I work on a team of 4 developers using EF5, everyone working on their own local database. Up until now we've been using automatic migrations but we're nearing the point where we need to release to production so we've disabled automatic migrations and started adding explicit code-based migrations.

Here is the problem: I ran the Update-Database command after a developer created a new explicit migration and I get the following error:

Applying code-based migrations: [201209080142319_CreatedDate.LastModifiedDate.Additions].
Applying code-based migration: 201209080142319_CreatedDate.LastModifiedDate.Additions.
Applying automatic migration:    201209080142319_CreatedDate.LastModifiedDate.Additions_AutomaticMigration.
Automatic migration was not applied because it would result in data loss.

Why do I get this error even though I've disabled automatic migrations? I can fix this error by deleting the explicit migration and then re-scaffolding it (running Add-Migration). Then Update-Database runs fine and doesn't mention anything about 'Automatic migration...' Also, the code in the migration created by me when I run Add-Migration is identical to the one created by my teammate. I don't see why it would even try to do an automatic migration since AutomaticMigrationsEnabled = false;.

What am I missing here?

Answer 1

I hate to answer my own question but I encountered this problem again. A developer on my team re-enabled automatic migrations on their local machine and then created an explicit migration, which reproduced this behavior as soon as I ran it.

Entity framework will always run an automatic migration before it runs an explicit migration that has the Source property defined in its .resx file, even if AutomaticMigrationsEnabled = false. An explicit migration will only have the Source property set if it is created after an automatic migration has been run.

The upshot is that disabling automatic migrations only means that EF won't automatically upgrade your schema when it detects model changes - but it might still do an automatic migration if it needs to fill in a gap between some explicit migrations. To avoid this behavior, don't use a mixture of automatic migrations and explicit migrations.