Code first migrations not being seen

Question

I'm fairly new to Entity Framework and I am having trouble getting it to apply my code first migrations to a new database. I think my migrations have gotten into a bad state.

I started out with an existing database, so I created an initial empty migration using

Add-Migration Initial -IgnoreChanges

That worked fine. Then I added a new entity and created another migration

Add-Migration New_Entity

That worked fine. I could apply these migrations to an existing database that didn't even have a __MigrationHistory table and it would be properly updated.

Fast forward a few days and a few commits later. I now have a new "clean" database that I want to apply the migrations to. I got into Visual Studio, point my app.config file at the new database, run

Update-Database

And it tells me

Unable to update database to match the current model because there are pending changes and automatic migration is disabled. Either write the pending model changes to a code-based migration or enable automatic migration. Set DbMigrationsConfiguration.AutomaticMigrationsEnabled to true to enable automatic migration. You can use the Add-Migration command to write the pending model changes to a code-based migration.

However, I do not have any pending models changes. Nothing has changed. But just to see what would happen, I ran

Add-Migration x

and it created a new migration that would add every entity in the model to the database. Basically starting over as if I had no migrations. So I deleted that one then re-added with the -IgnoreChanges flag. That gives me another blank one. If then run

Update-Database

It runs the x migration but totally ignores the migrations I created a few days ago (Initial and New_Entity). It's like it doesn't know they exist.

Obviously something is in a bad state but I'm not sure what I can do to get it back. I can't just delete and recreate the migrations because I need a blank one and one with just the new entity. I can't just comment out the entity temporarily because a lot of code already depends on it.

How did I get myself into this mess and how do I get out?

Answer 1

Alright, I got to the bottom of this. Turns out that somehow (I can't recall how at this point) the namespace inside the Configuration.cs file (inside the Migrations folder) was changed. Apparently this is enough to confuse the system into not seeing your other migrations. I thought at first it was simply because it was out of synch with the actual migration classes that had been generated. However, I tried changing the migration classes' namespaces to match the new namespace value of Congiguration.cs but the migrations still failed. It only worked after I reverted Configuration.cs back to its old namespace value.

Not really sure exactly what the deal is here. Maybe the original namespace was stored in the migration resx files and it noticed they didn't match anymore?