Confusing migrations after upgrade from 6 to 7

[MoazAlkharfan]

So I've been trying to upgrade ef core to 7 preview to test out the new features
after upgrading the packages I generate a new migration so any changes will be applied
What we're seeing here is multiple problems:

• The most obvious problem is it's generating non user friendly column names that can't be used for someone querying the database directly ex: ForeignKeyToAnotherTable changing to ForeignKey1 which is a big no no
• The second problem is what you see below is it's dropping foreign keys, renaming columns, renaming indexes, then adding the foreign key to a DIFFERENT table than the one it's supposed to!
  • The column Activity<User>Id was renamed to ActivityEvent_ActivityId1
  • The foreign key FK_Events_UserActivities_Activity<User>Id was renamed to FK_Events_CompanyActivities_ActivityEvent_ActivityId1
  • The same foreign key was pointing before to table UserActivities now it points to CompanyActivities

Include your code

No full reproduction, request if needed, it will take at least 3 days before i can provide a trimmed down working reproduction

This is a trimmed down version of the entities so it becomes easier to understand the structure being used

public abstract class Entity
{
    public string Id { get; set; }
}

public class Event<TTarget> : Entity
    where TTarget : class
{
    public virtual TTarget Target { get; set; }

    protected Event() { }

    public Event(TTarget target)
    {
        Target = target;
    }
}

public abstract class Activity<T> : Entity
    where T : class
{
    public virtual T Target { get; set; }

    public virtual List<ActivityEvent<T>> Events { get; private set; }
}

public abstract class ActivityEvent<TTarget> : Event<Activity<TTarget>>
    where TTarget : class
{
    protected ActivityEvent() { }

    protected ActivityEvent(Activity<TTarget> target)
        : base(target)
    {
    }
}

public class Company : Entity
{
    public virtual List<Activity<Company>> Activities { get; set; }
}

public class User : Entity
{
    public virtual List<Activity<User>> Activities { get; set; }
}


public class CompanyActivityConfiguration : IEntityTypeConfiguration<Activity<Company>>
{
    public void Configure(EntityTypeBuilder<Activity<Company>> builder)
    {
        builder.HasMany(x => x.Events)
            .WithOne(x => x.Target)
            .OnDelete(DeleteBehavior.Restrict);

        builder.ToTable(x => x.IsTemporal());
    }
}

public class UserActivityConfiguration : IEntityTypeConfiguration<Activity<User>>
{
    public void Configure(EntityTypeBuilder<Activity<User>> builder)
    {
        builder.HasMany(x => x.Events)
            .WithOne(x => x.Target)
            .OnDelete(DeleteBehavior.Restrict);

        builder.ToTable(x => x.IsTemporal());
    }
}


public class AppDbContext : DbContext
{
    public DbSet<Activity<User>> UserActivities { get; private set; } = null!;

    public DbSet<Activity<Company>> CompanyActivities { get; private set; } = null!;
    
    public DbSet<Event> Events { get; private set; } = null!;
    
    public AppDbContext(DbContextOptions<AppDbContext> options)
        : base(options)
    {
    }

    protected override void OnModelCreating(ModelBuilder builder)
    {
        builder.ApplyConfigurationsFromAssembly(typeof(AppDbContext).Assembly);
    }
}

Initial migration that was generated with ef core 6

namespace project.Migrations
{
    public partial class Initial : Migration
    {
        protected override void Up(MigrationBuilder migrationBuilder)
        {
           
            // ommited
            // ...
           
            migrationBuilder.AddForeignKey(
                name: "FK_Events_UserActivities_Activity<User>Id",
                schema: "app",
                table: "Events",
                column: "Activity<User>Id",
                principalSchema: "app",
                principalTable: "UserActivities",
                principalColumn: "Id");

            // ommited
            // ...
        }

        // ommited
       // ...
    }
}

Migration generated directly after upgrading from ef core 6 to ef core 7-preview

namespace project.Migrations
{
    /// <inheritdoc />
    public partial class Ef7Update : Migration
    {
        /// <inheritdoc />
        protected override void Up(MigrationBuilder migrationBuilder)
        {
           
            // ommited
            // ...
           
            migrationBuilder.DropForeignKey(
                name: "FK_Events_UserActivities_Activity<User>Id",
                schema: "app",
                table: "Events");

            // ommited
            // ...
           
            migrationBuilder.RenameColumn(
                name: "Activity<User>Id",
                schema: "app",
                table: "Events",
                newName: "ActivityEvent_ActivityId1")
                .Annotation("SqlServer:IsTemporal", true)
                .Annotation("SqlServer:TemporalHistoryTableName", "EventsHistory")
                .Annotation("SqlServer:TemporalHistoryTableSchema", "app")
                .Annotation("SqlServer:TemporalPeriodEndColumnName", "PeriodEnd")
                .Annotation("SqlServer:TemporalPeriodStartColumnName", "PeriodStart");

            // omitted code
            // ...

            migrationBuilder.RenameIndex(
                name: "IX_Events_Activity<User>Id",
                schema: "app",
                table: "Events",
                newName: "IX_Events_ActivityEvent_ActivityId1");

            migrationBuilder.AddForeignKey(
                name: "FK_Events_CompanyActivities_ActivityEvent_ActivityId1",
                schema: "app",
                table: "Events",
                column: "ActivityEvent_ActivityId1",
                principalSchema: "app",
                principalTable: "CompanyActivities",
                principalColumn: "Id");

            // omitted code
            // ...

        }

        // omitted code
        // ...
    }
}

Include provider and version information

EF Core version: 7.0.0-rc.2.22452.1
Database provider: Microsoft.EntityFrameworkCore.SqlServer
Target framework: .NET 7.0

[ajcvickers]

Note from triage: revert the naming breaking change.

[AndriySvyryd]

@MoazAlkharfan I've reverted the naming change, but for the other issues I'd need a complete repro. Try the next daily build or the public release of rc2 when it comes out and open a new issue if you are experiencing problems.