Unknown type for deserialization when trying to get enum collection in C#

[alexvab]

Hello, I have an issue with the api endpoint (controller action) which return collection of C# enum as a json
this is my swagger.json file:

{
  "openapi": "3.0.1",
  "info": {
    "title": "KiotaTestApi.WebApi",
    "version": "1.0"
  },
  "paths": {
    "/api/TestData/just-enums": {
      "get": {
        "tags": [
          "TestData"
        ],
        "responses": {
          "200": {
            "description": "Success",
            "content": {
              "text/plain": {
                "schema": {
                  "type": "array",
                  "items": {
                    "$ref": "#/components/schemas/KiotaTestApi.Models.Export.MyTaskStatus"
                  }
                }
              },
              "application/json": {
                "schema": {
                  "type": "array",
                  "items": {
                    "$ref": "#/components/schemas/KiotaTestApi.Models.Export.MyTaskStatus"
                  }
                }
              },
              "text/json": {
                "schema": {
                  "type": "array",
                  "items": {
                    "$ref": "#/components/schemas/KiotaTestApi.Models.Export.MyTaskStatus"
                  }
                }
              }
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "KiotaTestApi.Models.Export.MyTaskStatus": {
        "enum": [
          "Pending",
          "InProgress",
          "Done"
        ],
        "type": "string"
      }
    }
  }
}

Here is my controller action definition

    /// <summary>
    /// Get task statuses
    /// </summary>
    /// <returns></returns>
    [HttpGet("just-enums")]
    [ProducesResponseType(StatusCodes.Status200OK)]
    public async Task<ActionResult<IReadOnlyCollection<MyTaskStatus>>> GetStatuses()

When I'm using Kiota ApiClient that has been generated using this swagger.json file above I get an exception when GetAsync method is executed

System.InvalidOperationException: unknown type for deserialization System.Nullable`1[[KiotaTestApi.ApiClient.Models.MyTaskStatus, KiotaTestApi.ApiClient, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]
   at Microsoft.Kiota.Serialization.Json.JsonParseNode.GetCollectionOfPrimitiveValues[T]()+MoveNext()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at KiotaTestApi.ApiClient.Api.TestData.JustEnums.JustEnumsRequestBuilder.GetAsync(Action`1 requestConfiguration, CancellationToken cancellationToken) 

It seems like enum was handled as a primitive type in GetCollectionOfPrimitiveValues but there is no option for enum there:

...
if(genericType == TypeConstants.BooleanType)
                        yield return (T)(object)currentParseNode.GetBoolValue()!;
                    else if(genericType == TypeConstants.ByteType)
                        yield return (T)(object)currentParseNode.GetByteValue()!;
                    else if(genericType == TypeConstants.SbyteType)
                        yield return (T)(object)currentParseNode.GetSbyteValue()!;
                    else if(genericType == TypeConstants.StringType)
                        yield return (T)(object)currentParseNode.GetStringValue()!;
                    else if(genericType == TypeConstants.IntType)
                        yield return (T)(object)currentParseNode.GetIntValue()!;
                    else if(genericType == TypeConstants.FloatType)
                        yield return (T)(object)currentParseNode.GetFloatValue()!;
                    else if(genericType == TypeConstants.LongType)
                        yield return (T)(object)currentParseNode.GetLongValue()!;
                    else if(genericType == TypeConstants.DoubleType)
                        yield return (T)(object)currentParseNode.GetDoubleValue()!;
                    else if(genericType == TypeConstants.GuidType)
                        yield return (T)(object)currentParseNode.GetGuidValue()!;
                    else if(genericType == TypeConstants.DateTimeOffsetType)
                        yield return (T)(object)currentParseNode.GetDateTimeOffsetValue()!;
                    else if(genericType == TypeConstants.TimeSpanType)
                        yield return (T)(object)currentParseNode.GetTimeSpanValue()!;
                    else if(genericType == TypeConstants.DateType)
                        yield return (T)(object)currentParseNode.GetDateValue()!;
                    else if(genericType == TypeConstants.TimeType)
                        yield return (T)(object)currentParseNode.GetTimeValue()!;
                    else
                        throw new InvalidOperationException($"unknown type for deserialization {genericType.FullName}");

.....

This is my GetAsync method:

 public async Task<List<MyTaskStatus?>?> GetAsync(Action<RequestConfiguration<DefaultQueryParameters>>? requestConfiguration = default, CancellationToken cancellationToken = default)
        {
#nullable restore
#else
        public async Task<List<MyTaskStatus?>> GetAsync(Action<RequestConfiguration<DefaultQueryParameters>> requestConfiguration = default, CancellationToken cancellationToken = default)
        {
#endif
            var requestInfo = ToGetRequestInformation(requestConfiguration);
            var collectionResult = await RequestAdapter.SendPrimitiveCollectionAsync<MyTaskStatus?>(requestInfo, default, cancellationToken).ConfigureAwait(false);
            return collectionResult?.ToList();
        }

So I'm wondering is this a know issue, or it is something that not supported by Kiota? (I was using versions 1.12 and 1.13)

Please let me know if you need more information.

Thanks!

[andrueastman]

Transferring this to the json serialization library repository.

[andrueastman]

Thanks for raising this @alexvab

This is related to #199 and the function you pointed out should ideally be handling enum collections in the meantime until the time a breaking change is made to allow for this scenario to align with other languages.

Any chance you'd be willing to submit a PR to fix this?

[alexvab]

Hi @andrueastman Thanks. I could try to submit PR but not sure when I'd be able to make. It looks like I can use Java implementation as a reference for this?

[baywet]

@andrueastman I think we could get around to that without introducing a breaking change by adding an early case here to check whether the generic type parameter is an enum, and route the call to the GetCollectionOfEnumValues instead.
@alexvab is this something you'd like to explore and submit a pull request for?

[alexvab]

@baywet yes I'd like to explore it and submit PR. but not sure how much time I'll have on hand and when I'll be able to submit PR.

[baywet]

great, let's circle back in a week.

[microsoft-github-policy-service]

This issue has been automatically marked as stale because it has been marked as requiring author feedback but has not had any activity for 4 days. It will be closed if no further activity occurs within 3 days of this comment.

[baywet]

@alexvab is this something you started looking at?

[microsoft-github-policy-service]

This issue has been automatically marked as stale because it has been marked as requiring author feedback but has not had any activity for 4 days. It will be closed if no further activity occurs within 3 days of this comment.

[andrueastman]

Ping @alexvab

[microsoft-github-policy-service]

This issue has been automatically marked as stale because it has been marked as requiring author feedback but has not had any activity for 4 days. It will be closed if no further activity occurs within 3 days of this comment.

[andrueastman]

Transferring issue as part of #238

[andrueastman]

Resolved with #291