NRE in linq processing of custom components

[zgabi]

With the latest version (5.3.10) of NHibernate I receive a NullReferenceException.
Version 5.3.9 works

.NET 6 RC2

Query:

DataManager.Query<WeatherDataType>(transaction).FirstOrDefault(t => t.Identification.SensorCode == sensorCode)

[Property(0, TypeType = typeof(WeatherDataIdentificationCompositeUserType))]
[Column(1, Name = nameof(WeatherDataIdentification.DateOfSampling), Unique = false, NotNull = false, Index = "WEATHER_DATEOFSAMPLING")]
[Column(2, Name = nameof(WeatherDataIdentification.InternalId), Unique = false, NotNull = false)]
[Column(3, Name = nameof(WeatherDataIdentification.Position) + "_Latitude", Unique = false, NotNull = false)]
[Column(4, Name = nameof(WeatherDataIdentification.Position) + "_Longitude", Unique = false, NotNull = false)]
[Column(5, Name = nameof(WeatherDataIdentification.SensorCode), Unique = false, NotNull = false)]
[Column(6, Name = nameof(WeatherDataIdentification.SensorId), Unique = false, NotNull = false)]
public virtual WeatherDataIdentification Identification...

StackTrace:

System.NullReferenceException: Object reference not set to an instance of an object.
   at NHibernate.Util.ExpressionsHelper.TryGetMappedNullability(ISessionFactoryImplementor sessionFactory, Expression expression, Boolean& nullable)
   at NHibernate.Linq.Visitors.NullableExpressionDetector.IsNullable(MemberExpression memberExpression, BinaryExpression equalityExpression)
   at NHibernate.Linq.Visitors.NullableExpressionDetector.IsNullable(Expression expression, BinaryExpression equalityExpression)
   at NHibernate.Linq.Visitors.HqlGeneratorExpressionVisitor.TranslateEqualityComparison(BinaryExpression expression)
   at NHibernate.Linq.Visitors.HqlGeneratorExpressionVisitor.VisitExpression(Expression expression)
   at NHibernate.Linq.Visitors.QueryModelVisitor.VisitWhereClause(WhereClause whereClause, QueryModel queryModel, Int32 index)
   at Remotion.Linq.QueryModelVisitorBase.VisitBodyClauses(ObservableCollection`1 bodyClauses, QueryModel queryModel)
   at Remotion.Linq.QueryModelVisitorBase.VisitQueryModel(QueryModel queryModel)
   at NHibernate.Linq.Visitors.QueryModelVisitor.Visit()
   at NHibernate.Linq.Visitors.QueryModelVisitor.GenerateHqlQuery(QueryModel queryModel, VisitorParameters parameters, Boolean root, Nullable`1 rootReturnType)
   at NHibernate.Linq.NhLinqExpression.Translate(ISessionFactoryImplementor sessionFactory, Boolean filter)
   at NHibernate.Hql.Ast.ANTLR.ASTQueryTranslatorFactory.CreateQueryTranslators(IQueryExpression queryExpression, String collectionRole, Boolean shallow, IDictionary`2 filters, ISessionFactoryImplementor factory)
   at NHibernate.Engine.Query.QueryPlanCache.GetHQLQueryPlan(IQueryExpression queryExpression, Boolean shallow, IDictionary`2 enabledFilters)
   at NHibernate.Impl.AbstractSessionImpl.GetHQLQueryPlan(IQueryExpression queryExpression, Boolean shallow)
   at NHibernate.Impl.AbstractSessionImpl.CreateQuery(IQueryExpression queryExpression)
   at NHibernate.Linq.DefaultQueryProvider.PrepareQuery(Expression expression, IQuery& query)
   at NHibernate.Linq.DefaultQueryProvider.Execute(Expression expression)
   at NHibernate.Linq.DefaultQueryProvider.Execute[TResult](Expression expression)

[PleasantD]

I'm seeing almost this exact error (top 4 levels of the stack trace map exactly).
In our case this happens when trying to perform logical comparisons on a custom type mapped using ICompositeUserType.
eg) query.Where(x => x.Email.Domain == "example.com").ToList()

[PleasantD]

I've tracked this a little further,
It looks like the exception is occurring here:

nhibernate-core/src/NHibernate/Util/ExpressionsHelper.cs

Line 166 in c4174f9

nullable = componentType.PropertyNullability[index];

It turns out that NHibernate.Type.CompositeCustomType.PropertyNullability returns null, so the indexing on that line fails.

I think what needs to happen there is that if componentType is CompositeCustomType then we can "inherit" the nullability from the nullability of the "parent" property. This could be accomplished by removing the last element of the memberPath and letting the logic continue with the entityPersister property logic.

Can anyone confirm?