Hi.

I have entity that had moved from one namespace to another, name and structure of entity don't changed.

Problem occurs when solution run in PerformSafely mode.

First of all, I don't see Unsafe action, but solution throwed ReferentialConstraintViolation.

I was disappointed, when see that I lost data in DB.

Created a test project. Bug repeated.

Test project:

namespace ConsoleApplication1
{
    using Xtensive.Orm;
    using Xtensive.Orm.Configuration;

    class Program
    {
        static void Main(string[] args)
        {
            var cfg = new DomainConfiguration("sqlserver", "Data Source=localhost; Initial Catalog=do40-tests; Integrated Security=True;")
            {
                UpgradeMode = DomainUpgradeMode.Recreate,
                ValidationMode = ValidationMode.OnDemand,
                NamingConvention = new NamingConvention { NamingRules = NamingRules.UnderscoreDots }
            };

            cfg.Sessions.Add(new SessionConfiguration("Default")
            {
                BatchSize = 25,
                DefaultIsolationLevel = SessionConfiguration.DefaultDefaultIsolationLevel,
                CacheSize = 1000,
                Options = SessionOptions.Default | SessionOptions.AutoTransactionOpenMode | SessionOptions.AutoTransactionSuppressMode
            });

            cfg.Types.Register(typeof(Program).Assembly);

            var domain = Domain.Build(cfg);

            var s = domain.OpenSession();
            s.Activate();

            // For recreate
            using (var tr = s.OpenTransaction())
            {
                var link = new EntityB { TestField = "EntityB" };

                new EntityA { TestField = "EntityA", TestLink = link };

                tr.Complete();
            }
        }
    }

    [HierarchyRoot]
    public class BaseEntity : Entity
    {
        [Field, Key]
        public int Id { get; private set; }
    }

    /// <summary>
    /// First entity
    /// </summary>
    [HierarchyRoot]
    public class EntityA : Entity
    {
        [Field, Key]
        public int Id { get; private set; }

        /// <summary>
        /// TestField
        /// </summary>
        [Field]
        public string TestField { get; set; }

        /// <summary>
        /// TestLink
        /// </summary>
        [Field(Nullable = false)]
        public EntityB TestLink { get; set; }
    }
}

EntityB:

namespace ConsoleApplication1
{
    using Xtensive.Orm;

    /// <summary>
    /// Second entity
    /// </summary>
    [HierarchyRoot]
    public class EntityB : Entity
    {
        [Field, Key]
        public int Id { get; private set; }

        /// <summary>
        /// TestField
        /// </summary>
        [Field]
        public string TestField { get; set; }
    }
}

Run solution.

Now change namespace for EntityB, add using to main file and set UpgradeMode = DomainUpgradeMode.PerformSafely

Run solution.

Exception:

SQL error occured.
Storage error details 'Entity: EntityB; Field: Id (FieldInfo);'
SQL error details 'Type: ReferentialConstraintViolation; Database: DO40-Tests; Table: EntityB; Column: Id; Constraint: FK_EntityA_TestLink_EntityB;'
Query 'ALTER TABLE [dbo].[EntityA] ADD CONSTRAINT [FK_EntityA_TestLink_EntityB] FOREIGN KEY ([TestLink_Id]) REFERENCES [dbo].[EntityB] ([Id]);'
Original message 'The ALTER TABLE statement conflicted with the FOREIGN KEY constraint "FK_EntityA_TestLink_EntityB". The conflict occurred in database "DO40-Tests", table "dbo.EntityB", column 'Id'.'

Go to DB and check data in table EntityB, it's empty!

However, adding RenameTypeHint fix situation, but i think erase data without warning it's huge bug!

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