[C#] Autorest client not generated for endpoints with file parameters

Problem

I have an endpoint that allows uploading a file. After updating to the latest version of Autorest, I can’t generate a client anymore and receive a generic error. I went through the issues here but didn’t find an answer. I’m still using OpenApi2.0 spec. According to the spec, I’m setting all the parameters needed. Running autorest with --verbose --debug parameters didn’t give me any additional info.

Failing example

{
  "swagger": "2.0",
  "info": {
    "title": "test",
    "description": "test",
    "version": "v1"
  },
  "paths": {
    "/logo": {
      "put": {
        "tags": [
          "test"
        ],
        "summary": "test",
        "description": "test",
        "operationId": "test",
        "consumes": [
          "multipart/form-data"
        ],
        "produces": [
        ],
        "parameters": [
          {
            "in": "formData",
            "name": "formFile",
            "description": "The file to upload.",
            "required": true,
            "type": "file"
          }
        ],
        "responses": {
          "204": {
            "description": "Success."
          }
        }
      }
    }
  },
  "definitions": {
  },
  "securityDefinitions": {
  }
}

Error details

FATAL: System.ArgumentNullException: Value cannot be null.
Parameter name: source
   at System.Linq.Enumerable.Select[TSource,TResult](IEnumerable1 source, Func2 selector)
   at AutoRest.Modeler.Model.RequestBody.AsParameters() in /opt/vsts/work/1/s/src/Model/RequestBody.cs:line 38
   at AutoRest.Modeler.SwaggerModeler.Unwrap(SwaggerParameter swaggerParameter) in /opt/vsts/work/1/s/src/SwaggerModeler.cs:line 452
   at AutoRest.Modeler.OperationBuilder.BuildMethodParameters(Method method) in /opt/vsts/work/1/s/src/OperationBuilder.cs:line 255
   at AutoRest.Modeler.OperationBuilder.BuildMethod(HttpMethod httpMethod, String url, String methodName, String methodGroup) in /opt/vsts/work/1/s/src/OperationBuilder.cs:line 100
   at AutoRest.Modeler.SwaggerModeler.BuildMethod(HttpMethod httpMethod, String url, String name, Operation operation) in /opt/vsts/work/1/s/src/SwaggerModeler.cs:line 404
   at AutoRest.Modeler.SwaggerModeler.Build(ServiceDefinition serviceDefinition) in /opt/vsts/work/1/s/src/SwaggerModeler.cs:line 106
   at AutoRest.Modeler.Program.<ProcessInternal>d__2.MoveNext() in /opt/vsts/work/1/s/src/Program.cs:line 60
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at NewPlugin.<Process>d__15.MoveNext()
/private/var/root/.autorest/@autorest_core@3.0.6262/node_modules/@autorest/core/dist/lib/pipeline/pipeline.js - FAILURE {}
Process() cancelled due to exception : Plugin imodeler1 reported failure. / Error: Plugin imodeler1 reported failure.
    at /private/var/root/.autorest/@autorest_core@3.0.6262/node_modules/@autorest/core/dist/lib/pipeline/plugins/external.js:26:19
    at async ScheduleNode (/private/var/root/.autorest/@autorest_core@3.0.6262/node_modules/@autorest/core/dist/lib/pipeline/pipeline.js:294:33)
  Error: Plugin imodeler1 reported failure.

Autorest version

autorest --info
AutoRest code generation utility [cli version: 3.0.6187; node: v12.13.0, max-memory: 8192 gb]
(C) 2018 Microsoft Corporation.
https://aka.ms/autorest


Showing All Installed Extensions

 Type       Extension Name                           Version      Location 
 core       @autorest/core                           3.0.6262     /var/root/.autorest/@autorest_core@3.0.6262
 extension  @microsoft.azure/autorest.csharp         2.3.84       /var/root/.autorest/@microsoft.azure_autorest.csharp@2.3.84
 extension  @microsoft.azure/autorest.modeler        2.3.55       /var/root/.autorest/@microsoft.azure_autorest.modeler@2.3.55

Maybe related issues:

• https://github.com/Azure/autorest/issues/3441;
• https://github.com/Azure/autorest.csharp/issues/169;
• https://github.com/Azure/autorest/issues/3433 - for OpenAPI v3;
• https://github.com/Azure/autorest/issues/3187;

[ANovitsky]

Why all issues about it closed? This is not resolved yet!.

We cannot use “in”: “formData”, every time error. For file or for string.

[nfidirko]

@OzBob, @fearthecowboy, thanks for your answers. unfortunately, it still doesn’t work with autorest v3.0.6262

Using:

"type": "object",
"format": "file"

causes another error:

ERROR: Schema violation: Data does not match any schemas from 'oneOf'

I ended up using an older version of autorest: 2.0.4413