Model building: Cycles not detected properly

[smitpatel]

Following model should throw exception in model validation.

public class Blog
{
    public int Id { get; set; }
    public int Id2 { get; set; }
    public int Fk { get; set; }
    public Post Post { get; set; }
}

public class Post
{
    public int Id { get; set; }
    public int Fk { get; set; }
    public Blog Blog { get; set; }
}

modelBuilder.Entity<Blog>(b =>
{
    b.HasOne(e => e.Post).WithMany().HasForeignKey(e => e.Id2);
    b.HasMany<Post>()
        .WithOne(p => p.Blog)
        .HasForeignKey(p => new {p.Id, p.Fk})
        .HasPrincipalKey(e => new {e.Id2, e.Fk});
});

[ajcvickers]

@smitpatel Can you explain why it should throw?

[AndriySvyryd]

I thought it could be represented by a simpler model, but now I think we should still support it as is.

[smitpatel]

It throws exception while migrating database. Do we detect cycles or let SqlServer throw instead?

Unhandled Exception: System.Data.SqlClient.SqlException: Introducing FOREIGN KEY constraint 'FK_Post_Blog_Id_Fk' on table 'Post' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints.

[ajcvickers]

Is this different from the normal issue SQL Server has with cascade paths, as described in #6956?

[smitpatel]

No. I will close this one then.