DbMigrator trying to execute every migration, not detecting executed migrations - entity-framework

Question

I am trying to create a service call that will update an EF code first database to the latest version. However, it is always trying (and failing obviously) to execute all migrations, whether they were executed already or not.
Here's my code:
var config = new DbMigrationsConfiguration<MyContext>();
config.MigrationsAssembly = typeof (MyContext).Assembly;
config.MigrationsNamespace = "Context.Migrations";
//This had no effect
//config.SetHistoryContextFactory(connectionString.ProviderName, (connection, s) => new HistoryContext(context.Database.Connection, "dbo"));
var migrator = new DbMigrator(config);
//This gets every single migration, even the ones already executed before
var migrations = migrator.GetPendingMigrations();
//This gets 0 migrations
var existing = migrator.GetDatabaseMigrations();
//This gets all migrations
var other = migrator.GetLocalMigrations();
//This returns true! So it knows all the migrations are already executed
var differ = context.Database.CompatibleWithModel(true);
//This will throw an exception because it's trying to create existing tables!
migrator.Update();
I can confirm that the migration history table contains [dbo].[__MigrationHistory] references all the old migrations.
I checked the connection strings in the migrator. I also tried setting the history context factory manually in case it is looking somewhere else with no result. Also, running update-database directly from the console works and says no pending updates.
Any help is appreciated

Answer 1

Make sure DbMigrationsConfiguration.ContextKey is set correctly.
The default value after this line
var config = new DbMigrationsConfiguration<MyContext>();
will be like this
"System.Data.Entity.Migrations.DbMigrationsConfiguration`1[MyContextNamespace.MyContext]"
You need to add the following line
config.ContextKey = "{Your_Context_Key}";
If you don't know the context key, open your [dbo].[__MigrationHistory] table and look at the ContextKey column.
Once you set it up correctly, if your database is up-to-date, migrator.GetPendingMigrations() should return empty and migrator.GetDatabaseMigrations() should return all migrations.

Answer 2

If your database is all updated, and you have no need for the old migration tables, then what I would suggest that you do is delete the migrations folder and recreate it using
enable-migrations
I do it all the time when the migrations mess up. I never need the historical migrations - once they have done their job - they are DONE! Be sure to save your seed method if you are seeing through the configuration. You can look at my earlier post on this, maybe that will help too.
Migrations
Good luck.