Asp.Net Blazor DataContractSerializer.ReadObject exceptions in published code

[allderidge]

Description

A Asp.Net Blazor WASM based client has issues using the DataContractSerializer. DataContractSerializer.ReadObject correctly reads an object when run via visual studio but when published fails throwing an exception.

An example is available from the following repo: https://github.com/allderidge/BlazorBugReport_DataContractIssue

To reproduce the issue:

• Run the example.
• Observe that the main index page shows 'No Exception'.
• Publish the client and copy the files to a web server and browse to the published location.
• Observe the page displays a stack trace shown the DataContractSerializer.ReadObject failing.

It appears that property de-serialisation using a bool, bool? and int property types triggers the issue, a string property data type doesn't. Note that I haven't tested the full range of CLR types.

The following stack trace is generated:

System.NullReferenceException: Arg_NullReferenceException
    at System.Runtime.Serialization.CodeGenerator.Call(MethodInfo methodInfo)
    at System.Runtime.Serialization.XmlFormatReaderGenerator.CriticalHelper.ThrowValidationException()
    at System.Runtime.Serialization.XmlFormatReaderGenerator.CriticalHelper.ThrowValidationException(String msg, Object[] values)
    at System.Runtime.Serialization.XmlFormatReaderGenerator.CriticalHelper.ReadValue(Type type, String name, String ns)
    at System.Runtime.Serialization.XmlFormatReaderGenerator.CriticalHelper.ReadMembers(ClassDataContract classContract, Boolean[] requiredMembers, Label[] memberLabels, LocalBuilder memberIndexLocal, LocalBuilder requiredIndexLocal)
    at System.Runtime.Serialization.XmlFormatReaderGenerator.CriticalHelper.ReadMembers(ClassDataContract classContract, LocalBuilder extensionDataLocal)
    at System.Runtime.Serialization.XmlFormatReaderGenerator.CriticalHelper.ReadClass(ClassDataContract classContract)
    at System.Runtime.Serialization.XmlFormatReaderGenerator.CriticalHelper.GenerateClassReader(ClassDataContract classContract)
    at System.Runtime.Serialization.XmlFormatReaderGenerator.GenerateClassReader(ClassDataContract classContract)
    at System.Runtime.Serialization.ClassDataContract.CreateXmlFormatReaderDelegate()
    at System.Runtime.Serialization.ClassDataContract.get_XmlFormatReaderDelegate()
    at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, Type declaredType, DataContract& dataContract)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Type declaredType, DataContract dataContract, String name, String ns)
    at System.Runtime.Serialization.DataContractSerializer.InternalReadObject(XmlReaderDelegator xmlReader, Boolean verifyObjectName, DataContractResolver dataContractResolver)
    at System.Runtime.Serialization.XmlObjectSerializer.ReadObjectHandleExceptions(XmlReaderDelegator reader, Boolean verifyObjectName, DataContractResolver dataContractResolver)
    at System.Runtime.Serialization.XmlObjectSerializer.ReadObjectHandleExceptions(XmlReaderDelegator reader, Boolean verifyObjectName)
    at System.Runtime.Serialization.DataContractSerializer.ReadObject(XmlReader reader, Boolean verifyObjectName)
    at DataContractIssue.DeseriliseIssue.TryCreateIssue()

I've found a similar but different stack trace with de-serialisation of other class types:

Exception during login process: System.NullReferenceException: Arg_NullReferenceException
    at System.Runtime.Serialization.CodeGenerator.VerifyParameterCount(MethodInfo methodInfo, Int32 expectedCount)
    at System.Runtime.Serialization.CodeGenerator.Call(Object thisObj, MethodInfo methodInfo, Object param1)
    at System.Runtime.Serialization.XmlFormatReaderGenerator.CriticalHelper.CreateObject(ClassDataContract classContract)
    at System.Runtime.Serialization.XmlFormatReaderGenerator.CriticalHelper.GenerateClassReader(ClassDataContract classContract)
    at System.Runtime.Serialization.XmlFormatReaderGenerator.GenerateClassReader(ClassDataContract classContract)
    at System.Runtime.Serialization.ClassDataContract.CreateXmlFormatReaderDelegate()
    at System.Runtime.Serialization.ClassDataContract.get_XmlFormatReaderDelegate()
    at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, Type declaredType, DataContract& dataContract)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Type declaredType, DataContract dataContract, String name, String ns)
    at System.Runtime.Serialization.DataContractSerializer.InternalReadObject(XmlReaderDelegator xmlReader, Boolean verifyObjectName, DataContractResolver dataContractResolver)
    at System.Runtime.Serialization.XmlObjectSerializer.ReadObjectHandleExceptions(XmlReaderDelegator reader, Boolean verifyObjectName, DataContractResolver dataContractResolver)
    at System.Runtime.Serialization.XmlObjectSerializer.ReadObjectHandleExceptions(XmlReaderDelegator reader, Boolean verifyObjectName)
    at System.Runtime.Serialization.DataContractSerializer.ReadObject(XmlDictionaryReader reader, Boolean verifyObjectName)

Illustrative code

string message;
var serialiser = new DataContractSerializer(typeof(AuthOutcome), new DataContractSerializerSettings());

using (var output = new StringWriter())
using (var writer = new XmlTextWriter(output) { Formatting = Formatting.None })
{
	serialiser.WriteObject(writer, new AuthOutcome());
	message = output.GetStringBuilder().ToString();
}

using var reader = XmlReader.Create(new StringReader(message));

// the following line causes an exception to be thrown when running with published code
serialiser.ReadObject(reader, false);


public class AuthOutcome
{
	public bool PropertyTriggeringIssue { get; set; }
}

Configuration

• ASP.NET Core version: 5.0.0-preview.8.20414.8
• Include the output of dotnet --info

 Version:   5.0.100-preview.8.20417.9
 Commit:    fc62663a35

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.18363
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\5.0.100-preview.8.20417.9\

Host (useful for support):
  Version: 5.0.0-preview.8.20407.11
  Commit:  bf456654f9

.NET SDKs installed:
  2.1.504 [C:\Program Files\dotnet\sdk]
  2.1.602 [C:\Program Files\dotnet\sdk]
  2.1.700-preview-009601 [C:\Program Files\dotnet\sdk]
  3.0.100-preview4-011223 [C:\Program Files\dotnet\sdk]
  3.1.103 [C:\Program Files\dotnet\sdk]
  3.1.200 [C:\Program Files\dotnet\sdk]
  3.1.300-preview-015048 [C:\Program Files\dotnet\sdk]
  3.1.302 [C:\Program Files\dotnet\sdk]
  3.1.402 [C:\Program Files\dotnet\sdk]
  5.0.100-preview.8.20417.9 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.All 2.1.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.22 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.22 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0-preview4-19216-03 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.0-preview.8.20414.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.22 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0-preview4-27615-11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.0-preview.8.20407.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.0.0-preview4-27613-28 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.2 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.3 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.6 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.7 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.8 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.0-preview.8.20411.6 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

• The IDE (VS / VS Code/ VS4Mac) you're running on, and it's version
  Microsoft Visual Studio Enterprise 2019 Preview Version 16.8.0 Preview 2.1

Remarks

Preventing linking by adding the following properties to the project file helps:

    <BlazorWebassemblyEnableLinking>false</BlazorWebassemblyEnableLinking>

The example given here does not throw an exception. More complex scenarios such as de-serialising a type hierarchy still have issues though with the following exception thrown:

System.BadImageFormatException: Method has zero rva
    at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, Type declaredType, DataContract& dataContract)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 id, RuntimeTypeHandle declaredTypeHandle, String name, String ns)
    at System.Runtime.Serialization.CollectionDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, Type declaredType, DataContract& dataContract)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 id, RuntimeTypeHandle declaredTypeHandle, String name, String ns)
    at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, Type declaredType, DataContract& dataContract)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 id, RuntimeTypeHandle declaredTypeHandle, String name, String ns)
    at System.Runtime.Serialization.CollectionDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, Type declaredType, DataContract& dataContract)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Type declaredType, DataContract dataContract, String name, String ns)
    at System.Runtime.Serialization.DataContractSerializer.InternalReadObject(XmlReaderDelegator xmlReader, Boolean verifyObjectName, DataContractResolver dataContractResolver)
    at System.Runtime.Serialization.XmlObjectSerializer.ReadObjectHandleExceptions(XmlReaderDelegator reader, Boolean verifyObjectName, DataContractResolver dataContractResolver)
    at System.Runtime.Serialization.XmlObjectSerializer.ReadObjectHandleExceptions(XmlReaderDelegator reader, Boolean verifyObjectName)
    at System.Runtime.Serialization.DataContractSerializer.ReadObject(XmlDictionaryReader reader, Boolean verifyObjectName)

[lewing]

This looks like it is probably a duplicate of #42824

cc @eerhardt

[lewing]

@allderidge a Fix for this was merged into 5.0/release in #42911

[allderidge]

@lewing I can create a similar issue listed at the end in the Remarks section with BlazorWebassemblyEnableLinking set to false and within a debug launch from VS. Is it worth trying to create a sample for this, or is it likely the changes will fix all these type of issues and its best waiting?

[eerhardt]

Your last scenario looks like a separate issue. If you have an app that can reproduce the issue, please log it as a separate issue.