Owned attribute adds TempId column to principal entity when foreign key type has conversion

[Ropack]

This is breaking change between efcore 5 and efcore 6.

I have the following model where an owned entity has foreign key to another entity. The key property is of type MyId and thus needs a conversion to be configured.

If the owned entity is configured as owned via OwnedAttribute, then the referenced BarEntity entity by foreign key gets column TempId, which shouldn't be there (see the generated migration bellow).

If the owned entity is configured with modelBuilder in OnModelCreating method using .OwnsOne() (without using OwnedAttribute on OwnedBazEntity), the TempId column is not created (as expected).

Model

public class MyId
{
    public int Id { get; set; }
}

public class FooEntity
{
    public MyId Id { get; set; } = null!;
    public OwnedBazEntity OwnedBaz { get; set; } = null!;
}

public class BarEntity
{
    public MyId Id { get; set; } = null!;
}

[Owned]
public class OwnedBazEntity
{
    [ForeignKey(nameof(BarId))]
    public BarEntity? Bar { get; set; }

    public MyId? BarId { get; set; }
}

DbContext

public class MyDbContext : DbContext
{
    public DbSet<FooEntity> Foos { get; set; } = null!;
    public DbSet<BarEntity> Bars { get; set; } = null!;

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer(@"Server=(LocalDB)\MSSqlLocalDb;Database=EFCoreTest;Trusted_Connection=True");
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<FooEntity>()
            .Property(x => x.Id)
            .HasConversion(x => x.Id, x => new MyId { Id = x });

        modelBuilder.Entity<BarEntity>()
            .Property(x => x.Id)
            .HasConversion(x => x.Id, x => new MyId { Id = x });

        modelBuilder.Entity<FooEntity>()
            .OwnsOne(b => b.OwnedBaz);
    }
}

Create init migration

dotnet ef migrations add Init

Actual result

protected override void Up(MigrationBuilder migrationBuilder)
{
    migrationBuilder.CreateTable(
        name: "Bars",
        columns: table => new
        {
            Id = table.Column<int>(type: "int", nullable: false),

            // ========== This column shouldn't be here ========== 
            TempId = table.Column<int>(type: "int", nullable: false) 
        },
        constraints: table =>
        {
            table.PrimaryKey("PK_Bars", x => x.Id);
            table.UniqueConstraint("AK_Bars_TempId", x => x.TempId);
        });
    migrationBuilder.CreateTable(
        name: "Foos",
        columns: table => new
        {
            Id = table.Column<int>(type: "int", nullable: false),
            OwnedBaz_BarId = table.Column<int>(type: "int", nullable: true)
        },
        constraints: table =>
        {
            table.PrimaryKey("PK_Foos", x => x.Id);
            table.ForeignKey(
                name: "FK_Foos_Bars_OwnedBaz_BarId",
                column: x => x.OwnedBaz_BarId,
                principalTable: "Bars",
                principalColumn: "Id");
        });
    migrationBuilder.CreateIndex(
        name: "IX_Foos_OwnedBaz_BarId",
        table: "Foos",
        column: "OwnedBaz_BarId");
}

Expected result

protected override void Up(MigrationBuilder migrationBuilder)
{
    migrationBuilder.CreateTable(
        name: "Bars",
        columns: table => new
        {
            Id = table.Column<int>(type: "int", nullable: false)
            // ========== No TempId column ========== 
        },
        constraints: table =>
        {
            table.PrimaryKey("PK_Bars", x => x.Id);
        });
    migrationBuilder.CreateTable(
        name: "Foos",
        columns: table => new
        {
            Id = table.Column<int>(type: "int", nullable: false),
            OwnedBaz_BarId = table.Column<int>(type: "int", nullable: true)
        },
        constraints: table =>
        {
            table.PrimaryKey("PK_Foos", x => x.Id);
            table.ForeignKey(
                name: "FK_Foos_Bars_OwnedBaz_BarId",
                column: x => x.OwnedBaz_BarId,
                principalTable: "Bars",
                principalColumn: "Id");
        });
    migrationBuilder.CreateIndex(
        name: "IX_Foos_OwnedBaz_BarId",
        table: "Foos",
        column: "OwnedBaz_BarId");
}

Provider and version information

EF Core version: 6.0.2
Database provider: Microsoft.EntityFrameworkCore.SqlServer
Target framework: .NET 6.0
Nullability: enabled
Operating system: Win10 21H1 19043.1526
IDE: Visual Studio 2022 17.1 Preview 6.0

[epicbugs]

v6.0.6 has same bug even when entity is configured with modelBuilder in OnModelCreating method using .OwnsOne()

Is there a workaround that would prevent TempId column declarations from being generated into the migration?

[whambly]

Is there an update / solution to this issue? or a workaround?
I'm having the same issue with EFCore 6.0.6 having upgraded to NET 6.0

[AndriySvyryd]

A possible workaround could be calling modelBuilder.Entity<BarEntity>().HasNoKey(); on the principal table before configuring the conversion and to call modelBuilder.Entity<BarEntity>().HasKey(x => x.Id); afterwards

[DawidSieczka]

A possible workaround could be calling modelBuilder.Entity<BarEntity>().HasNoKey(); on the principal table before configuring the conversion and to call modelBuilder.Entity<BarEntity>().HasKey(x => x.Id); afterwards

FYI
The workaround doesn't work for modelBuilder.Entity<T>().HasKey(x => Guid1, Guid2, Guid3);
If you pass up to 2 params it works fine.