EFCore 8.0.7 Breaks Discriminator Generated Code

[WynieCronje]

File a bug

More Info:

I have tested this by downgrading each version. The expected behavior worked in 8.0.6 and started breaking in 8.0.7. I have a suspicion that it is related to the PR #33622 that fixed the isssue #33605 in commit: f08ecf3

Include your code

PatientLocator.cs

public abstract class PatientLocator : DomainEntity
{
   public int Discriminator { get; private set; }
   ....
}

EntityTypeConfiguration.cs

b.HasDiscriminator(p => p.Discriminator)
   .HasValue<PatientAddress>(0)
   .HasValue<PatientPhone>(1)
    .HasValue<PatientEmail>(2);

b.HasOne(p => p.Patient)
   .WithMany(p => p.Locators)
    .IsRequired()
    .OnDelete(DeleteBehavior.Cascade);

Snapshot on 8.0.6

 modelBuilder.Entity("DOH.CARS.Domain.PatientDirectory.PatientLocator", b =>
                {
                    b.Property<Guid>("Id")
                        .HasColumnType("uniqueidentifier")
                        .HasColumnName("PatientLocatorId");

                    b.Property<int>("Discriminator")
                        .HasColumnType("int");

                    b.Property<Guid>("PatientId")
                        .HasColumnType("uniqueidentifier");

                    b.Property<byte[]>("Timestamp")
                        .IsConcurrencyToken()
                        .ValueGeneratedOnAddOrUpdate()
                        .HasColumnType("rowversion");

                    b.HasKey("Id");

                    b.HasIndex("PatientId");

                    b.ToTable("PatientLocator");

                    b.HasDiscriminator<int>("Discriminator");

                    b.UseTphMappingStrategy();
                });

Snapshot on 8.0.7

            modelBuilder.Entity("DOH.CARS.Domain.PatientDirectory.PatientLocator", b =>
                {
                    b.Property<Guid>("Id")
                        .HasColumnType("uniqueidentifier")
                        .HasColumnName("PatientLocatorId");

                    b.Property<int>("Discriminator")
                        .HasColumnType("int");

                    b.Property<Guid>("PatientId")
                        .HasColumnType("uniqueidentifier");

                    b.Property<byte[]>("Timestamp")
                        .IsConcurrencyToken()
                        .ValueGeneratedOnAddOrUpdate()
                        .HasColumnType("rowversion");

                    b.HasKey("Id");

                    b.HasIndex("PatientId");

                    b.ToTable("PatientLocator");

                    b.HasDiscriminator();

                    b.UseTphMappingStrategy();
                });

The Diff:

Include stack traces

When running the add-migration. It fails to compile the snapshot with below error:
Ignore the line numbers, they seem incorrect. I know the above mentioned changes causes the issue. If I manually change to old value, it all works again

System.NullReferenceException: Object reference not set to an instance of an object.
   at DOH.CARS.Persistence.Migrations.AppDbContextModelSnapshot.<>c.<BuildModel>b__0_77(EntityTypeBuilder b) in /work/CARS - Clinical Appointment and Referral System/DOH.CARS.Persistance/Migrations/AppDbContextModelSnapshot.cs:line 4374
   at Microsoft.EntityFrameworkCore.ModelBuilder.Entity(String name, Action`1 buildAction)
   at DOH.CARS.Persistence.Migrations.AppDbContextModelSnapshot.BuildModel(ModelBuilder modelBuilder) in /work/CARS - Clinical Appointment and Referral System/DOH.CARS.Persistance/Migrations/AppDbContextModelSnapshot.cs:line 4358
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelSnapshot.CreateModel()
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelSnapshot.get_Model()
   at Microsoft.EntityFrameworkCore.Migrations.Design.MigrationsScaffolder.ScaffoldMigration(String migrationName, String rootNamespace, String subNamespace, String language)
   at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.AddMigration(String name, String outputDir, String contextType, String namespace)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigrationImpl(String name, String outputDir, String contextType, String namespace)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigration.<>c__DisplayClass0_0.<.ctor>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass3_0`1.<Execute>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)

Include provider and version information

EF Core version: Breaks in 8.0.7,8.0.8
Database provider: (e.g. Microsoft.EntityFrameworkCore.SqlServer)
Target framework: (e.g. .NET 8.0)
Operating system: Both Mac and Windows
IDE: (e.g. Both Visual Studio Code and Visual Studio 2022 17.8.5)

[ajcvickers]

@AndriySvyryd FYI, looks like a regression in a patch.

[AndriySvyryd]

Duplicate of #34201
Should be fixed in 8.0.9

[stevendarby]

@AndriySvyryd do you know when 8.0.9 is due? October patch tuesday?

[AndriySvyryd]

@stevendarby Yes, and it will be called 8.0.10. We had to skip 8.0.9 due to some issues during the release.