ArgumentNullException when Deserializing Inherit Class with empty Migration

I’ve found an Issue in my Project with deserializing via a Migration. I’ve created the following Example to reproduce the behaviour:

using ExtendedXmlSerializer;
using ExtendedXmlSerializer.Configuration;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Xml.Linq;

namespace Test
{
 class IssueExample
  {
    static void Main(string[] args)
    {
      var serializer = new ConfigurationContainer().Type<Base>().AddMigration(new EmptyMigration()).Create();
      var container = new Container { Content = new AnotherNameSpace.Inherit() };
      var xml = serializer.Serialize(container);
      var loaded = serializer.Deserialize<Container>(xml); //Throws System.ArgumentNullException
    }
  }

  public class Container
  {
    public Base Content { get; set; }
  }

  public class Base { }

  namespace AnotherNameSpace
  {
    public class Inherit : Base { }
  }

  public class EmptyMigration : IEnumerable<Action<XElement>>
  {
    public IEnumerator<Action<XElement>> GetEnumerator()
    {
      yield return x => { }; //Do nothing
    }

    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();

  }
}

The Key-Elements are the inherit class inside the container object and the empty migration which changes something. If you remove the namespace “AnotherNameSpace”, another exception appears. The whole thing has something to do with namespaces. In the following the stacktrace:

System.ArgumentNullException
  HResult=0x80004003
  Message=Value cannot be null.
Parametername: key
  Source=mscorlib
  StackTrace:
   at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)
   at ExtendedXmlSerializer.Core.Sources.CacheBase`2.Get(TKey key) in ExtendedXmlSerializer\Core\Sources\CacheBase.cs:line 34
   at ExtendedXmlSerializer.ContentModel.Identification.IdentityStore.Get(String name, String identifier) in ExtendedXmlSerializer\ContentModel\Identification\IdentityStore.cs:line 10
   at ExtendedXmlSerializer.ExtensionModel.Xml.IdentityMapper.Get(String name, String identifier) in ExtendedXmlSerializer\ExtensionModel\Xml\IdentityMapper.cs:line 17
   at ExtendedXmlSerializer.ContentModel.Reflection.TypePartReflector.Create(TypeParts parameter) in ExtendedXmlSerializer\ContentModel\Reflection\TypePartReflector.cs:line 24
   at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)
   at ExtendedXmlSerializer.Core.Sources.CacheBase`2.Get(TKey key) in ExtendedXmlSerializer\Core\Sources\CacheBase.cs:line 34
   at ExtendedXmlSerializer.ContentModel.Reflection.TypeParser.Create(String parameter) in ExtendedXmlSerializer\ContentModel\Reflection\TypeParser.cs:line 22
   at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)
   at ExtendedXmlSerializer.Core.Sources.CacheBase`2.Get(TKey key) in ExtendedXmlSerializer\Core\Sources\CacheBase.cs:line 34
   at ExtendedXmlSerializer.ContentModel.Reflection.ReflectionParser.Create(String parameter) in ExtendedXmlSerializer\ContentModel\Reflection\ReflectionParser.cs:line 41
   at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)
   at ExtendedXmlSerializer.Core.Sources.CacheBase`2.Get(TKey key) in ExtendedXmlSerializer\Core\Sources\CacheBase.cs:line 34
   at ExtendedXmlSerializer.ExtensionModel.Xml.FormatReaderContext.Get(String parameter) in ExtendedXmlSerializer\ExtensionModel\Xml\FormatReaderContext.cs:line 19
   at ExtendedXmlSerializer.ExtensionModel.Xml.XmlReader.Get(String parameter) in ExtendedXmlSerializer\ExtensionModel\Xml\XmlReader.cs:line 28
   at ExtendedXmlSerializer.ContentModel.Format.ParsedContent`1.Get(IFormatReader parameter) in ExtendedXmlSerializer\ContentModel\Format\ParsedContent.cs:line 16
   at ExtendedXmlSerializer.ContentModel.Format.ContextualReader`1.Get(IFormatReader parameter) in ExtendedXmlSerializer\ContentModel\Format\ContextualReader.cs:line 17
   at ExtendedXmlSerializer.ContentModel.DecoratedReader`1.Get(IFormatReader parameter) in ExtendedXmlSerializer\ContentModel\DecoratedReader.cs:line 26
   at ExtendedXmlSerializer.ContentModel.Reflection.TypedParsingReader.Get(IFormatReader parameter) in ExtendedXmlSerializer\ContentModel\Reflection\TypedParsingReader.cs:line 15
   at ExtendedXmlSerializer.ContentModel.TrackingReader`1.Get(IFormatReader parameter) in ExtendedXmlSerializer\ContentModel\TrackingReader.cs:line 13
   at ExtendedXmlSerializer.ContentModel.Members.Extensions.GetIfAssigned[T](IReader`1 this, IFormatReader reader) in ExtendedXmlSerializer\ContentModel\Members\Extensions.cs:line 12
   at ExtendedXmlSerializer.ContentModel.Serializer`1.Get(IFormatReader parameter) in ExtendedXmlSerializer\ContentModel\Serializer.cs:line 22
   at ExtendedXmlSerializer.ContentModel.Properties.Property`1.Get(IFormatReader parameter) in ExtendedXmlSerializer\ContentModel\Properties\Property.cs:line 17
   at ExtendedXmlSerializer.ContentModel.Reflection.Classification.FromAttributes(IFormatReader parameter) in ExtendedXmlSerializer\ContentModel\Reflection\Classification.cs:line 37
   at ExtendedXmlSerializer.ContentModel.Reflection.Classification.Get(IFormatReader parameter) in ExtendedXmlSerializer\ContentModel\Reflection\Classification.cs:line 31
   at ExtendedXmlSerializer.ContentModel.Reflection.Activation.RuntimeActivator.Get(IFormatReader parameter) in ExtendedXmlSerializer\ContentModel\Reflection\Activation.cs:line 61
   at ExtendedXmlSerializer.ExtensionModel.Xml.XmlInnerContentActivator.Get(IFormatReader parameter) in ExtendedXmlSerializer\ExtensionModel\Xml\XmlInnerContentActivator.cs:line 20
   at ExtendedXmlSerializer.ContentModel.Content.InnerContentReader.Get(IFormatReader parameter) in ExtendedXmlSerializer\ContentModel\Content\InnerContentReader.cs:line 21
   at ExtendedXmlSerializer.ContentModel.Members.Extensions.GetIfAssigned[T](IReader`1 this, IFormatReader reader) in ExtendedXmlSerializer\ContentModel\Members\Extensions.cs:line 12
   at ExtendedXmlSerializer.ContentModel.Serializer`1.Get(IFormatReader parameter) in ExtendedXmlSerializer\ContentModel\Serializer.cs:line 22
   at ExtendedXmlSerializer.ExtensionModel.Xml.MigrationsExtension.Contents.Serializer.Get(IFormatReader parameter) in ExtendedXmlSerializer\ExtensionModel\Xml\MigrationsExtension.cs:line 149
   at ExtendedXmlSerializer.ContentModel.Members.Extensions.GetIfAssigned[T](IReader`1 this, IFormatReader reader) in ExtendedXmlSerializer\ContentModel\Members\Extensions.cs:line 12
   at ExtendedXmlSerializer.ContentModel.Serializer`1.Get(IFormatReader parameter) in ExtendedXmlSerializer\ContentModel\Serializer.cs:line 22
   at ExtendedXmlSerializer.ContentModel.Members.MemberSerializer.Get(IFormatReader parameter) in ExtendedXmlSerializer\ContentModel\Members\MemberSerializer.cs:line 22
   at ExtendedXmlSerializer.ContentModel.Members.MemberHandler.Handle(IInnerContent contents, IMemberSerializer member) in ExtendedXmlSerializer\ContentModel\Members\MemberHandler.cs:line 13
   at ExtendedXmlSerializer.ContentModel.Content.InnerContentServices.Handle(IInnerContent contents, IMemberSerializer member) in ExtendedXmlSerializer\ContentModel\Content\InnerContentServices.cs:line 41
   at ExtendedXmlSerializer.ContentModel.Members.MemberInnerContentHandler.IsSatisfiedBy(IInnerContent parameter) in ExtendedXmlSerializer\ContentModel\Members\MemberInnerContentHandler.cs:line 29
   at ExtendedXmlSerializer.ContentModel.Content.InnerContentReader.Get(IFormatReader parameter) in ExtendedXmlSerializer\ContentModel\Content\InnerContentReader.cs:line 26
   at ExtendedXmlSerializer.ContentModel.Members.Extensions.GetIfAssigned[T](IReader`1 this, IFormatReader reader) in ExtendedXmlSerializer\ContentModel\Members\Extensions.cs:line 12
   at ExtendedXmlSerializer.ContentModel.Serializer`1.Get(IFormatReader parameter) in ExtendedXmlSerializer\ContentModel\Serializer.cs:line 22
   at ExtendedXmlSerializer.ContentModel.SerializerAdapter`1.Get(IFormatReader parameter) in ExtendedXmlSerializer\ContentModel\SerializerAdapter.cs:line 41
   at ExtendedXmlSerializer.ExtensionModel.Xml.Read.Get(XmlReader parameter) in ExtendedXmlSerializer\ExtensionModel\Xml\Read.cs:line 26
   at ExtendedXmlSerializer.ExtensionModel.Xml.Serializer.Deserialize(XmlReader reader) in ExtendedXmlSerializer\ExtensionModel\Xml\Serializer.cs:line 21
   at ExtendedXmlSerializer.ExtensionModel.Xml.ExtendedXmlSerializer.Deserialize(XmlReader reader) in ExtendedXmlSerializer\ExtensionModel\Xml\ExtendedXmlSerializer.cs:line 18
   at ExtendedXmlSerializer.ExtensionMethodsForSerialization.Deserialize[T](IExtendedXmlSerializer this, XmlReaderSettings settings, Stream stream) in ExtendedXmlSerializer\ExtensionMethodsForSerialization.cs:line 145
   at ExtendedXmlSerializer.ExtensionMethodsForSerialization.Deserialize[T](IExtendedXmlSerializer this, XmlReaderSettings settings, String data) in ExtendedXmlSerializer\ExtensionMethodsForSerialization.cs:line 121
   at ExtendedXmlSerializer.ExtensionMethodsForSerialization.Deserialize[T](IExtendedXmlSerializer this, String data) in ExtendedXmlSerializer\ExtensionMethodsForSerialization.cs:line 109
   at Test.IssueExample.Main(String[] args) in IssueExample.cs:line 17

  This exception was originally thrown at this call stack:
    [External Code]
    ExtendedXmlSerializer.Core.Sources.CacheBase<TKey, TValue>.Get(TKey) in CacheBase.cs
    ExtendedXmlSerializer.ContentModel.Identification.IdentityStore.Get(string, string) in IdentityStore.cs
    ExtendedXmlSerializer.ExtensionModel.Xml.IdentityMapper.Get(string, string) in IdentityMapper.cs
    ExtendedXmlSerializer.ContentModel.Reflection.TypePartReflector.Create(ExtendedXmlSerializer.ContentModel.Conversion.TypeParts) in TypePartReflector.cs
    [External Code]
    ExtendedXmlSerializer.Core.Sources.CacheBase<TKey, TValue>.Get(TKey) in CacheBase.cs
    ExtendedXmlSerializer.ContentModel.Reflection.TypeParser.Create(string) in TypeParser.cs
    [External Code]
    ExtendedXmlSerializer.Core.Sources.CacheBase<TKey, TValue>.Get(TKey) in CacheBase.cs
    ...
    [Call Stack Truncated]

[imperiobadgo]

It works just perfect. Older save can still be migrated and desirialized!

[Mike-E-angelo]

Woohoo! Glad to hear. Please let me know if you encounter any further issues. I will slate the fix release for next Tuesday and update here when available on Nuget. Please use the preview builds until then. 👍