LINQ query dynamic component by interface hangs the application

[nfplee]

I have the following query which executes fine:

var posts = await session.Query<BlogPost>()
    .Where(p => p.Attributes["Field1"] != null)
   .ToListAsync();

However if I change it to use an interface instead then the query hangs.

var posts = await session.Query<IBlogPost>()
    .Where(p => p.Attributes["Field1"] != null)
    .ToListAsync();

Please see the attached application which helps demonstrate this. This problem only happens when filtering against an attribute.

ConsoleApp1.zip

[bahusoid]

Infinite loop

nhibernate-core/src/NHibernate/Linq/Visitors/VisitorUtil.cs

Lines 27 to 50 in 6c70217

	while (metaData == null && targetObject != null &&
	(targetObject.NodeType == ExpressionType.MemberAccess || targetObject.NodeType == ExpressionType.Parameter ||
	targetObject is QuerySourceReferenceExpression))
	{
	System.Type memberType;
	if (targetObject is QuerySourceReferenceExpression)
	{
	var querySourceExpression = (QuerySourceReferenceExpression) targetObject;
	memberType = querySourceExpression.Type;
	}
	else if (targetObject.NodeType == ExpressionType.Parameter)
	{
	var parameterExpression = (ParameterExpression) targetObject;
	memberType = parameterExpression.Type;
	}
	else //targetObject.NodeType == ExpressionType.MemberAccess
	{
	var memberExpression = ((MemberExpression) targetObject);
	memberPath = memberExpression.Member.Name + "." + memberPath;
	memberType = memberExpression.Type;
	targetObject = memberExpression.Expression;
	}
	metaData = sessionFactory.GetClassMetadata(memberType);
	}

Introduced in #237 (4.0.0.Alpha2)

[bahusoid]

It's not a regression. It didn't stuck before #237 but failed in some other way - dynamic components on unmapped interface never worked in LINQ

[nfplee]

@bahusoid do you have a suggestion for a temporary fix?

[bahusoid]

do you have a suggestion for a temporary fix?

Map it as interface (ClassMapping<IBlogPost>)

[nfplee]

Thanks @bahusoid, I tried switching my class mapping from BlogPost to IBlogPost but this now makes the first query hang and the second query throws the exception "NHibernate.InstantiationException: 'Cannot instantiate abstract class or interface: '".

If I try mapping both BlogPost and IBlogPost then the first query now works again but the second query throws the same exception above.

[bahusoid]

the second query throws the exception "NHibernate.InstantiationException: 'Cannot instantiate abstract class or interface: '".

You have to specify concrete class in mapping too via Class<BlogPost>();.

[nfplee]

I already tried looking into this as this is what I do for my components. However the Class method is not available in the ClassMapping class. Looking into the code for the Class method against the ComponentMapping I tried adding:

CustomizersHolder.AddCustomizer(typeof(IBlogPost), m => m.Class(typeof(BlogPost)));

But this had no effect.