Change of MaxLength not migrated to DB

[mehrt]

I'm using beta8. So I don't think this is a dupe of #882, but maybe a followup on it.
I followed the steps given here.

If I do ...

modelBuilder.Entity<Blog>()
    .Property(b => b.Url)
    .IsRequired()
    .HasMaxLength(256);

... and run the initial migration, I get a Blog table with a column defined as Url (nvarchar(256), not null, as I would expect.
If I subsequently change this to ...

modelBuilder.Entity<Blog>()
    .Property(b => b.Url)
    .IsRequired()
    .HasMaxLength(512);

... and do Add-Migration / Update-Database, the field stays as it was in the db, even though the change in HasMaxLength is present in the ModelSnapshot class:

b.Property<string>("Url")
    .IsRequired()
    .Annotation("MaxLength", 512);

If the only thing I change for the second migration is the value for HasMaxLength as done above, I get the following Migration code:

public partial class MySecondMigration : Migration
{
    protected override void Up(MigrationBuilder migrationBuilder)
    {
    }
    protected override void Down(MigrationBuilder migrationBuilder)
    {
    }
}

Which probably is the reasony why the database isn't changed. If I manually change this to ...

public partial class MySecondMigration : Migration
{
    protected override void Up(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.AlterColumn<string>("Url", "Blog", "nvarchar(512)");
    }
    protected override void Down(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.AlterColumn<string>("Url", "Blog", "nvarchar(256)");
    }
}

... applying and reverting the second migration works as expected.
I assume it's a bug that a change of MaxLength in the model is not migrated to the database? Because if I remove the .IsRequired() from the model, the column is altered as it should be if I run the migration, so subsequent column changes actually do seem to work. If I modify two properties at once (ie. change IsRequired() and HasMaxLength), only the change of the first one is migrated to the db.

[sthossan]

I face this problem when I use EF Core code first. I change my migration code entity.Property(t => t.UserName).HasColumnType("varchar")..HasMaxLength(256) to entity.Property(t => t.UserName).HasColumnType("varchar(256)") and now it's working fine

[SalmanAerovative]

After redesigning my domain to not require a string with large length, i found that entity framework was not honoring my HasMaxLength() because I had configured it twice in two different locations.