Template: Numeric time series data points typed as DatapointString in GraphQL query result

Hi, 

I am trying to use templates to model domain specific connections between assets and time series in CDF, and I have come across an issue that I would like some feedback on.

If I have the following schema type:

type StringOrNumber @template {
  Asset: Asset
  NumericTS: TimeSeries
}

and do the following query:

query StringOrNumber {
  stringOrNumberQuery {
    items {
      NumericTS {
        __typename
        isString
        datapoints(limit: 1) {
          __typename
          timestamp
          value                    
        }
      }
    }
  }
}

then the datapoint output __typename has the value “DatapointString” even though the timeseries is not a string timeseries:

{
  "data": {
    "stringOrNumberQuery": {
      "items": [
        {
          "NumericTS": {
            "__typename": "TimeSeries",
            "isString": false,
            "datapoints": [
              {
                "__typename": "DatapointString",
                "timestamp": 1634534671570,
                "value": 14.3
              }
            ]
          }
        }
      ]
    }
  }
}

The values appear correctly in the query output, so I first noticed the problem when trying to use Strawberry Shake to auto-generate C# types from my query. It uses the __typename value to determine which class to instantiate when deserializing the results into its auto-generated classes - consequently I can not get the data values out since Strawberry Shake instantiates a class that expects “stringValue” in the result if the __typename equals “DatapointString”. 

I can work around it by hand coding my C# classes, but it seems either my understanding or the template implementation is incorrect. 

Best Regards,

Tom