SerializableType.ToBytes(object obj) throws exception in .net core

[billbarosa]

I am implementing an Audit Trail Manager in a .net core application. When I call @event.Collection.NeedsInserting(entryAdded, i, elemType), I get a NHibernate.Type.SerializationException.
Investigating this further showed me that the problem is in the ToBytes() method, especially when using the BinaryFormatter.

StackTrace:

NHibernate.Type.SerializationException: Could not serialize a serializable property:  ---> System.Runtime.Serialization.SerializationException: Type 'System.Reflection.PropertyInfo' in Assembly 'System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e' is not marked as serializable.
   at System.Runtime.Serialization.FormatterServices.InternalGetSerializableMembers(Type type)
   at System.Runtime.Serialization.FormatterServices.<>c.<GetSerializableMembers>b__5_0(MemberHolder mh)
   at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)
   at System.Runtime.Serialization.FormatterServices.GetSerializableMembers(Type type, StreamingContext context)
   at System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitMemberInfo()
   at System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitSerialize(Type objectType, ISurrogateSelector surrogateSelector, StreamingContext context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter converter, SerializationBinder binder)
   at System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Write(WriteObjectInfo objectInfo, NameInfo memberNameInfo, NameInfo typeNameInfo)
   at System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Serialize(Object graph, BinaryFormatterWriter serWriter, Boolean fCheck)
   at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Serialize(Stream serializationStream, Object graph, Boolean check)
   at NHibernate.Type.SerializableType.ToBytes(Object obj)
   --- End of inner exception stack trace ---
   at NHibernate.Type.SerializableType.ToBytes(Object obj)
   at NHibernate.Type.SerializableType.IsEqual(Object x, Object y)
   at NHibernate.Collection.Generic.PersistentGenericBag`1.NeedsInserting(Object entry, Int32 i, IType elemType)

[fredericDelaporte]

It looks like you have some invalid SerializableType mapped. You have to determine which entity class triggers the issue and check its class definition, its mapping, its property custom types if any, ...

[hazzik]

It could be a bug... I’ll check.

[hazzik]

It errors because BinaryFormatter does not have a surrogate provider set that we're using to serialize members of System.Reflection namespace (PropertyInfo, etc). But the question is: why is it trying to [de-]serialize property info? And do we want to pre-configure or allow setting the surrogates provider in SerializableType?

@billbarosa can you provide an example what is the value of the entryAdded?

It seems likely it is a proxy, so you would neet to unproxy it before calling @event.Collection.NeedsInserting(entryAdded, i, elemType)

[billbarosa]

@hazzik event is a PreCollectionUpdateEvent, I iterate all entries in the collection, below is an example.

var i = -1;
foreach (var entryAdded in @event.Collection.Entries(collectionPersister))
{
    ++i;
    var elemType = NHibernateUtil.GetSerializable(type);
    if ([email protected](entryAdded, i, elemType)) continue;

Unproxy the entryAdded does not have any effect.

I tried using the Surrogate provider in the Tobytes method and I had no problem. So I will try to fix it.

[fredericDelaporte]

If it is a lazy property proxy, it can not be unproxied. A test-case reproducing the issue would help checking what is actually going on.