XmlSerializer now serializes properties of object type properly

[hmemcpy]

Who's affected

Users with V5.X endpoints configured to use XML message serialization, when using fields of type System.Object that are assigned primitive or simple (e.g. Guid, DateTime) types.

Symptoms

Serialization will not generate namespaces for simple types, and deserialization will fail, since the message element does not have all the appropriate namespaces.

Steps to reproduce

Trying to serialize, then deserialize the following type fill fail, when the Value property is assigned a simple type, e.g. Guid:

public class SerializedPair
{
    public string Key { get; set; }
    public object Value { get; set; }
}

Workaround

none

Original bug report

I'm currently upgrading from NServiceBus 4.7.5 to NServiceBus 5.2.4, and when using the XmlSerializer, I noticed that it generates an invalid XML message when I try to serialize a message -
the namespaces for the simple types are no longer declared, but they're still used in the document.

For example, if I try to serialize a message that exposes a SerializedPair property that is defined as follows:

public class SerializedPair
{
    public string Key { get; set; }
    public object Value { get; set; }
}

in 4.7.5 it would be serialized as:

<?xml version="1.0"?>
<Messages xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
          xmlns:xsd="http://www.w3.org/2001/XMLSchema" 
          xmlns="http://tempuri.net/xxx.Crm.ServiceBusMessages" 
          xmlns:guid="Guid" xmlns:int32="Int32" 
          xmlns:string="String" 
          xmlns:datetime="DateTime" 
          xmlns:boolean="Boolean" 
          xmlns:decimal="Decimal">
    <UpdateContact>
        <SerializedPair>
            <Key>AddressId</Key>
            <guid:Value>ebdeeb33-baa7-4100-b1aa-eb4d6816fd3d</guid:Value>
        </SerializedPair>
       ....

In 5.2.4, it gets serialized as:

<?xml version="1.0" ?>
<UpdateContact xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
               xmlns:xsd="http://www.w3.org/2001/XMLSchema" 
               xmlns="http://tempuri.net/xxx.Crm.ServiceBusMessages">
    <SerializedPair>
        <Key>AddressId</Key>
        <guid:Value>70a22cd7-64fd-4d6d-ab13-2ad7800addc7</guid:Value>
    </SerializedPair>
    ....

Note that the "Messages" element is no longer present, and the "xmlns:guid" namespace declaration is also missing, which makes this invalid XML.
How do I get NServiceBus to generate valid xml again?

For completeness, my BusConfiguration looks like:

BusConfiguration busConfiguration = new BusConfiguration();
busConfiguration.UseSerialization<XmlSerializer>();
busConfiguration.UseTransport<MsmqTransport>();
ISendOnlyBus bus = Bus.CreateSendOnly(busConfiguration);

This was originally posted in http://stackoverflow.com/q/31943814/90882

[andreasohlund]

Messages root beening gone is fine but the namespace issue seems like a critical bug to me

[andreasohlund]

@hmemcpy updating description to point out that it only affects V5 endpoints