dotnet-svcutil silently failing to deserialize responses

[brent-williams]

Describe the bug
The proxy from dotnet-svcutil connects to the server, serializes and sends a request ok, and elicits a correct response from WFC server. But deserialization fails without error and I simply get null returned. Under .NET Framework 4.8 the wsdl.exe-generated proxy there is deserializing fine.

To Reproduce
The SOAP server is fixed and beyond my control. However, I have captured the relevant SOAP request & response in Fiddler, attached with the relevant WSDL. Connect/operation code below, nothing special. Note in main() I am using @shmao's workaround from #2219 to avoid the 'JScript/CSharp scripts is not supported' proxy exception i.e.:

            MethodInfo method = typeof(XmlSerializer).GetMethod("set_Mode", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static);
            method.Invoke(null, new object[] { 1 });

Proxy generated with dotnet-svcutil --sync --outputDir . http://XXX/?WSDL. The generated proxy fails to generate unless all Namespace="" attribute arguments are removed, possibly related. I added EventListener and dumping everything down Verbose from all event sources, lots of output but nothing at all around the deserialization failure.

Putting dotnet-svcutil aside I wrote manual Channel-based MessageContract/DataContract wrappers, ultimately I get the same null result. I am unable to shape the Response classes so that attached SOAP response will deserialize under WCF with a non-null result.

Confirmed the null result occurs using dotnet-svcutil 2.0.1 with System.ServiceModel.* 4.7.0 under both .NET Core 3.0 and 3.1 on both Windows 10 and macOS Catalina.

Expected behavior
A populated response object. Failing that, an exception to help narrow down the problem. Failing that, even just some hack to get at the raw response string in case of failure, that way I could at least use the proxy for requests & tear apart the response manually (regex/xpath/etc.).

Screenshots
Attached fiddler.

Additional context
Connection code

      WSWebServiceSoapPortClient proxy;
      try {
        proxy = new WSWebServiceSoapPortClient(new BasicHttpBinding(),
          new EndpointAddress("http://XXX"));

        await proxy.OpenAsync();
      } catch (Exception e) {
        Console.WriteLine(e.Message);
        return;
      }

      if (proxy.State == System.ServiceModel.CommunicationState.Faulted) {
        System.Console.WriteLine("Unable to connect to the proxy.");
        return;
      }

      var one = new WSUserLoginRequest1(new WSUserLoginRequest() {
        userName = "XXX",
        userPassword = "XXX",
      });
      WSUserLoginResponse1 wsUserLoginResponse = null;

      try {
        wsUserLoginResponse = await proxy.WSUserLoginAsync(one);   // returns null
      } catch (Exception e) {
        Console.WriteLine(e.ToString());
        return;
      }

Relevant WSDL, can send in full on private channel if required.

<?xml version="1.0" encoding="UTF-8"?>
<wsdl:definitions xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/" 
  xmlns:http="http://schemas.xmlsoap.org/wsdl/http/" 
  xmlns:mime="http://schemas.xmlsoap.org/wsdl/mime/" 
  xmlns:s="http://www.w3.org/2001/XMLSchema" 
  xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/" 
  xmlns:soap12="http://schemas.xmlsoap.org/wsdl/soap12/" 
  xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" 
  xmlns:tm="http://microsoft.com/wsdl/mime/textMatching/" 
  xmlns:tns="WSWebService" name="WSWebService" targetNamespace="WSWebService">
  <wsdl:types>
    <schema xmlns="http://www.w3.org/2001/XMLSchema" targetNamespace="WSWebService">

      ...

      <s:complexType name="WSUserLoginRequest">
        <s:sequence>
          <s:element name="userName" type="s:string" />
          <s:element name="userPassword" type="s:string" />
        </s:sequence>
      </s:complexType>
      <s:complexType name="WSUserLoginResponse">
        <s:sequence>
          <s:element name="userToken" type="s:string" />
          <s:element name="wsdlVersion" type="s:string" minOccurs="1" maxOccurs="1" default="2.0.0.0" />
          <s:element name="result" type="s:int" />
          <s:element name="resultString" type="s:string" />
        </s:sequence>
      </s:complexType>

      ...

      <wsdl:message name="WSUserLoginSoapIn">
        <wsdl:part name="parameters" type="tns:WSUserLoginRequest" />
      </wsdl:message>
      <wsdl:message name="WSUserLoginSoapOut">
        <wsdl:part name="parameters" type="tns:WSUserLoginResponse" />
      </wsdl:message>

      ...

      <wsdl:operation name="WSUserLogin">
        <wsdl:documentation>Authenticate user using provided username and password.</wsdl:documentation>
        <wsdl:input message="tns:WSUserLoginSoapIn" />
        <wsdl:output message="tns:WSUserLoginSoapOut" />
      </wsdl:operation>

[brent-williams]

Added to stackflow as well (https://stackoverflow.com/questions/60332365/net-core-3-1-dotnet-svcutil-generated-wcf-proxy-and-even-a-custom-channel-a), critical blocker for us.

[StephenBonikowsky]

@brent-williams We will need the full wsdl so we can reproduce the issue, also for a visual examination the part of the wsdl with all the contract info is very useful.
If you need to hide the endpoint address it should be fine for you to edit that out.

[brent-williams]

Hi @StephenBonikowsky thanks for reply. Unfortunately I can't send full WSDL without private channel + NDA, however I have stripped it down to the method in question. dotnet-svcutil runs produces similar output against the below as it does the full WSDL. Is this sufficient for you to attempt a dup?

<?xml version="1.0" encoding="UTF-8"?>
<wsdl:definitions xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/" 
  xmlns:http="http://schemas.xmlsoap.org/wsdl/http/" 
  xmlns:mime="http://schemas.xmlsoap.org/wsdl/mime/" 
  xmlns:s="http://www.w3.org/2001/XMLSchema" 
  xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/" 
  xmlns:soap12="http://schemas.xmlsoap.org/wsdl/soap12/" 
  xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" 
  xmlns:tm="http://microsoft.com/wsdl/mime/textMatching/" 
  xmlns:tns="WSWebService" name="WSWebService" targetNamespace="WSWebService">
  <wsdl:types>
    <schema xmlns="http://www.w3.org/2001/XMLSchema" targetNamespace="WSWebService">
      <s:complexType name="WSUserLoginRequest">
        <s:sequence>
          <s:element name="userName" type="s:string" />
          <s:element name="userPassword" type="s:string" />
        </s:sequence>
      </s:complexType>
      <s:complexType name="WSUserLoginResponse">
        <s:sequence>
          <s:element name="userToken" type="s:string" />
          <s:element name="wsdlVersion" type="s:string" minOccurs="1" maxOccurs="1" default="2.0.0.0" />
          <s:element name="result" type="s:int" />
          <s:element name="resultString" type="s:string" />
        </s:sequence>
      </s:complexType>
    </schema>
  </wsdl:types>
  <wsdl:message name="WSUserLoginSoapIn">
    <wsdl:part name="parameters" type="tns:WSUserLoginRequest" />
  </wsdl:message>
  <wsdl:message name="WSUserLoginSoapOut">
    <wsdl:part name="parameters" type="tns:WSUserLoginResponse" />
  </wsdl:message>
  <wsdl:portType name="WSWebServiceSoapPort">
    <wsdl:operation name="WSUserLogin">
      <wsdl:documentation>Documentation</wsdl:documentation>
      <wsdl:input message="tns:WSUserLoginSoapIn" />
      <wsdl:output message="tns:WSUserLoginSoapOut" />
    </wsdl:operation>
  </wsdl:portType>
  <wsdl:binding name="WSWebServiceSoapBinding" type="tns:WSWebServiceSoapPort">
    <soap:binding style="rpc" transport="http://schemas.xmlsoap.org/soap/http" />
    <wsdl:operation name="WSUserLogin">
      <soap:operation soapAction="WSUserLogin" style="rpc" />
      <wsdl:input>
        <soap:body use="literal" namespace="WSWebService" />
      </wsdl:input>
      <wsdl:output>
        <soap:body use="literal" namespace="WSWebService" />
      </wsdl:output>
    </wsdl:operation>
  </wsdl:binding>
  <wsdl:service name="WSWebService">
    <wsdl:port name="WSWebServiceSoapPort" binding="tns:WSWebServiceSoapBinding">
      <soap:address location="https://x.x.x.x:x" />
    </wsdl:port>
  </wsdl:service>
</wsdl:definitions>

[StephenBonikowsky]

@brent-williams We'll have someone work on a repro and see if there is anything else we need.
@imcarolwang Could you have someone work on reproducing this issue?

[StephenBonikowsky]

@mconnew Is there any other info we could use to help @imcarolwang reproduce the issue.

[mconnew]

It looks like there's enough of the WSDL there to reproduce the generated client code. Just to note, this isn't a WCF service. He's also provided screenshots of a request and response so we know what to mock out the server response to be. I think we have everything needed.

[brent-williams]

Great anything I can do to help let me know. True the server is not WCF, was written in C/gSOAP.

[brent-williams]

FYI this problem was duped & a workaround found for the stripped-down-wsdl only on stackoverflow (https://stackoverflow.com/questions/60332365/dotnet-svcutil-generated-wcf-proxy-and-even-a-custom-channel-are-returning-n). A solution to generate a usable proxy directly from dotnet-svcutil for the full wsdl remains outstanding.

[StephenBonikowsky]

We have a repro now.
Will need to get some cycles freed-up to investigate this further.

@brent-williams You said this is a blocker for you, does the workaround found on stackoverflow unblock you?