NHibernate.MappingException - Trouble Shooting Checklist (no persister for)

Question

Here's a starter list:

1. if hbm is hand generated, is it an embedded resource?
2. if using FNH, does it pass a PerssistenceSpecification test?
3. if not using FNH, can you save and then load the persisted class?
4. use Ayende's "sanity checks"

I'm sure many of you have gotten this one at one point or another. But have you ever gotten it when you knew your mapping was set up correctly?

I started getting this exception after I started using a new repository design, but only in one scenario! PersistenceSpecification tests pass, as do all repository methods (using SQLite).

The scenario that leads to the exception is when legacy projects from a different db are converted to green field system. The legacy system is from a different database and has it's own session factory, which should be irrelevant because the error comes after previously unconverted Projects are retrieved and in memory.

As the routine tries to save these unconverted Projects into the new database, the exception is thrown, full stack trace below.

Any ideas on how to build up the trouble shooting check list and solves this problem?

Cheers, Berryl

=== the Exception trace =====

failed: NHibernate.MappingException : No persister for: Smack.ConstructionAdmin.Domain.Model.Projects.Project
at NHibernate.Impl.SessionFactoryImpl.GetEntityPersister(String entityName)
at NHibernate.Impl.SessionImpl.GetEntityPersister(String entityName, Object obj)
at NHibernate.Engine.ForeignKeys.IsTransient(String entityName, Object entity, Nullable`1 assumed, ISessionImplementor session)
at NHibernate.Event.Default.AbstractSaveEventListener.GetEntityState(Object entity, String entityName, EntityEntry entry, ISessionImplementor source)
at NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.PerformSaveOrUpdate(SaveOrUpdateEvent event)
at NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.OnSaveOrUpdate(SaveOrUpdateEvent event)
at NHibernate.Impl.SessionImpl.FireSaveOrUpdate(SaveOrUpdateEvent event)
at NHibernate.Impl.SessionImpl.SaveOrUpdate(Object obj)
NHibernate\Repository\FabioNHibRepository.cs(46,0): at Smack.Core.Data.NHibernate.Repository.FabioNHibRepository`1.Add(T item)
LegacyConversion\LegacyBatchUpdater.cs(20,0): at Smack.ConstructionAdmin.Data.LegacyConversion.LegacyBatchUpdater.ConvertOpenLegacyProjects(ILegacyProjectDao legacyProjectDao, IProjectRepository greenProjectRepository)
Data\Brownfield\ProjectBatchUpdate_SQLiteTests.cs(19,0): at Smack.ConstructionAdmin.Tests.Data.Brownfield.ProjectBatchUpdate_SQLiteTests.Test()

Answer 1

The problem here turned out to be that I was inadvertently binding the same session context to both the legacy and greenfield db session factories, first to the greenfield and then the legacy.