Fluent-NHibernate mapping throws "Bad identifier type: System.Guid"

I would like some assistance on how to troubleshoot a mappingexception that provides no detail. Er, OK -- there's plenty of detail just not a class or property.

For starters, I just upgraded to NH3.1 and FNH 1.2. I have an class that I use to build a SQLite database for NHibernate (3.1.0.4000). I am having trouble trying to isolate the fluent-nhibernate(1.2.0.712) mapping that is the problem.

The error is:

System.InvalidCastException: Unable to cast object of type 'NHibernate.Type.SerializableType' to type 'NHibernate.Type.IIdentifierType'. at NHibernate.Engine.UnsavedValueFactory.GetUnsavedIdentifierValue(String unsavedValue, IGetter identifierGetter, IType identifierType, ConstructorInfo constructor) NHibernate.MappingException: Bad identifier type: System.Guid at NHibernate.Engine.UnsavedValueFactory.GetUnsavedIdentifierValue(String unsavedValue, IGetter identifierGetter, IType identifierType, ConstructorInfo constructor) at NHibernate.Tuple.PropertyFactory.BuildIdentifierProperty(PersistentClass mappedEntity, IIdentifierGenerator generator) at NHibernate.Tuple.Entity.EntityMetamodel..ctor(PersistentClass persistentClass, ISessionFactoryImplementor sessionFactory) at NHibernate.Persister.Entity.AbstractEntityPersister..ctor(PersistentClass persistentClass, ICacheConcurrencyStrategy cache, ISessionFactoryImplementor factory) at NHibernate.Persister.Entity.SingleTableEntityPersister..ctor(PersistentClass persistentClass, ICacheConcurrencyStrategy cache, ISessionFactoryImplementor factory, IMapping mapping) at NHibernate.Persister.PersisterFactory.CreateClassPersister(PersistentClass model, ICacheConcurrencyStrategy cache, ISessionFactoryImplementor factory, IMapping cfg) at NHibernate.Impl.SessionFactoryImpl..ctor(Configuration cfg, IMapping mapping, Settings settings, EventListeners listeners) at NHibernate.Cfg.Configuration.BuildSessionFactory() at MYPROJ.DatabaseConfigurer.OpenSession(DbEnum database) in DatabaseConfigurer.cs: line 37 at MYPROJ.user_specification.<.ctor>b__5() in UserSpecs.cs: line 670

Guid? What Guid? I don't have a Guid as an identifier anywhere in my mappings. I do have one Guid in a class as a property -- I use the guid to batch records for processing by a service; not an identifier.

I get the error on this line where I instantiate an in-memory SQLiteConfiguration using fluent-nhibernate (1.2.0.712):

var sessionFactory = configuration.BuildSessionFactory();

I turned on log4net basic configuration to log to a file, but can't find any errors. Here is the tail of that log:

2011-05-12 15:29:04,152 [1] ?.lambda_method(:0) - processing filters (second pass)
2011-05-12 15:29:04,199 [1] ?.lambda_method(:0) - Using dialect: NHibernate.Dialect.SQLiteDialect
2011-05-12 15:29:04,277 [1] ?.lambda_method(:0) - Using dialect defined converter
2011-05-12 15:29:04,277 [1] ?.lambda_method(:0) - Generate SQL with comments: disabled
2011-05-12 15:29:04,277 [1] ?.lambda_method(:0) - Initializing connection provider: NHibernate.Connection.DriverConnectionProvider
2011-05-12 15:29:04,277 [1] ?.lambda_method(:0) - Configuring ConnectionProvider
2011-05-12 15:29:04,277 [1] ?.lambda_method(:0) - Transaction factory: NHibernate.Transaction.AdoNetWithDistributedTransactionFactory
2011-05-12 15:29:04,293 [1] ?.lambda_method(:0) - Optimize cache for minimal puts: False
2011-05-12 15:29:04,293 [1] ?.lambda_method(:0) - Connection release mode: on_close
2011-05-12 15:29:04,293 [1] ?.lambda_method(:0) - Default batch fetch size: 1
2011-05-12 15:29:04,293 [1] ?.lambda_method(:0) - echoing all SQL to stdout
2011-05-12 15:29:04,293 [1] ?.lambda_method(:0) - Statistics: disabled
2011-05-12 15:29:04,293 [1] ?.lambda_method(:0) - Deleted entity synthetic identifier rollback: disabled
2011-05-12 15:29:04,293 [1] ?.lambda_method(:0) - Query translator: NHibernate.Hql.Ast.ANTLR.ASTQueryTranslatorFactory
2011-05-12 15:29:04,293 [1] ?.lambda_method(:0) - Query language substitutions: {'true'='1', 'false'='0'}
2011-05-12 15:29:04,293 [1] ?.lambda_method(:0) - cache provider: NHibernate.Cache.NoCacheProvider, NHibernate, Version=3.1.0.4000, Culture=neutral, PublicKeyToken=aa95f207798dfdb4
2011-05-12 15:29:04,293 [1] ?.lambda_method(:0) - Wrap result sets: disabled
2011-05-12 15:29:04,293 [1] ?.lambda_method(:0) - Batcher factory: NHibernate.AdoNet.NonBatchingBatcherFactory, NHibernate, Version=3.1.0.4000, Culture=neutral, PublicKeyToken=aa95f207798dfdb4
2011-05-12 15:29:04,293 [1] ?.lambda_method(:0) - Default entity-mode: Poco
2011-05-12 15:29:04,293 [1] ?.lambda_method(:0) - Named query checking : enabled
2011-05-12 15:29:04,324 [1] ?.lambda_method(:0) - building session factory
2011-05-12 15:29:04,324 [1] ?.lambda_method(:0) - Session factory constructed with filter configurations : {}
2011-05-12 15:29:04,324 [1] ?.lambda_method(:0) - instantiating session factory with properties: {'connection.provider'='NHibernate.Connection.DriverConnectionProvider', 'proxyfactory.factory_class'='NHibernate.ByteCode.Castle.ProxyFactoryFactory, NHibernate.ByteCode.Castle', 'connection.driver_class'='NHibernate.Driver.SQLite20Driver, NHibernate, Version=3.1.0.4000, Culture=neutral, PublicKeyToken=aa95f207798dfdb4', 'dialect'='NHibernate.Dialect.SQLiteDialect, NHibernate, Version=3.1.0.4000, Culture=neutral, PublicKeyToken=aa95f207798dfdb4', 'hibernate.dialect'='NHibernate.Dialect.SQLiteDialect, NHibernate, Version=3.1.0.4000, Culture=neutral, PublicKeyToken=aa95f207798dfdb4', 'query.substitut开发者_运维百科ions'='true=1;false=0', 'connection.release_mode'='on_close', 'show_sql'='true', 'connection.connection_string'='Data Source=:memory:;Version=3;New=True;'}
2011-05-12 15:29:04,324 [1] ?.lambda_method(:0) - Obtaining IDbConnection from Driver
2011-05-12 15:29:04,324 [1] ?.lambda_method(:0) - Closing connection

Log4net didn't provide any insight, is there another way I can debug this exception to reveal maybe the class or property?

Thanks

EDIT I use an IIdConvention for setting up my primary keys and ahem my pants are on fire: I use Elmah, which has a GUID for ErrorId. I will see if I can test the incoming instance in my convention for the proper UnsavedValue set for integers versus a Guid for Elmah. I will test this tomorrow and post the answer.

I just removed the Elmah from test mapping and it builds fine now.

Engine.UnsavedValueFactory.GetUnsavedIdentifierValue is throwing the error because 0 is not a valid default value for a GUID.

I had a Fluent NHibernate ID convention that was previously setting all IDs with a default value of 0, and this broke with the change from 2.* to 3.1.0.4000.