BsonSerializer fails to resolve custom serializer. StackOverflow exception when register derived serializers

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    • Type: Bug
    • Resolution: Gone away
    • Priority: Major - P3
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    • Affects Version/s: 2.11.4
    • Component/s: Serialization
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      It looks like BsonSerializer fails to resolve proper serializer for a member when declared member type doesn't match actual initialized type.

      Observed code flow (might not be exact):

      • BsonMemberMap looks up serializer and calls .Serialize() on found serializer (via extension method I believe).
      • Matched serializer of type ClassSerializerBase<T> calls Serialize() method on base class.
        Serialize() method looks up serializer on actual runtime type (e.g. value.GetType()) which fails to  find serializer for a concrete type.

      If you register concrete type serializer as well, driver fails with StackOverflow exception because of infinite serializer lookup loop.

      Please take a look at minimal repro below.

      class Program
{
        public class Root
        {
            // Initialized type doesn't match declared type!!!
            public IDictionary<int, Node> Nodes { get; set; } 
               = new Dictionary<int, Node>();
        }        

        public class Node
        { 
            public string Name { get; set; }
        }        

        static void Main(string[] args)
        {
            BsonSerializer.RegisterSerializer(typeof(IDictionary<int, Node>),
                GetInt32Serializer<Node>());            

            var root = new Root();
            root.Nodes.Add(0, new Node { Name = "Test" }); 

            using (var stringWriter = new StringWriter())
            {
                using (var writer = new JsonWriter(stringWriter))
                {
                    BsonSerializer.Serialize(writer, root);                     
                    Console.WriteLine("Valid Root: {0}", stringWriter.ToString());
                }
            }            
            Console.ReadKey();
        }   

        private static IBsonSerializer GetInt32Serializer<TValue>()
        {
            return new DictionaryInterfaceImplementerSerializer<IDictionary<int, TValue>, int, TValue>(
                DictionaryRepresentation.Document,
                new Int32Serializer(BsonType.String),
                BsonSerializer.SerializerRegistry.GetSerializer<TValue>());
        }
    }

            Assignee:
            James Kovacs
            Reporter:
            Eduard Muradov
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            Watchers:
            4 Start watching this issue

              Created:
              Updated:
              Resolved: