GraphQL Mesh gRPC defaults bug demo

This project demonstrates a bug in the GraphQL Mesh where the option to load the default gRPC values does not have any effect.

Reproduce the issue

Run Demo gRPC service

• navigate to the demo_service folder
• run go mod download to download dependencies
• run make start to start the gRPC service

Run GraphQL Mesh

• open a second terminal
• navigate to the mesh folder
• run yarn install
• run yarn start-mesh

Example query

• navigate to http://localhost:4000/graphql
• run the following query:

{
  DemoService_GetSomeData(input: {}) {
    data {
      someTextData,
      someEnum
    }
  }
}

The response:

{
  "data": {
    "DemoService_GetSomeData": {
      "data": [
        {
          "someTextData": "data 0",
          "someEnum": null
        },
        {
          "someTextData": "data 1",
          "someEnum": "ENUM_ONE"
        }
      ]
    }
  }
}

The issue Please note that the first someEnum value is null. The gRPC service is responding with ENUM_ZERO (the default value) and therefore this response is expected with the default configuration. Nevertheless, when the mesh configuration specifies the load defaults option:

    - name: DemoService
      handler:
        grpc:
          endpoint: localhost:9003
          source:
            load:
              defaults: true
            file: ../service_go/service_proto/demo_service.proto

Then the expected behavior is to fill the value with the default value and the expected response would be:

{
  "data": {
    "DemoService_GetSomeData": {
      "data": [
        {
          "someTextData": "data 0",
          "someEnum": "ENUM_ZERO"
        },
        {
          "someTextData": "data 1",
          "someEnum": "ENUM_ONE"
        }
      ]
    }
  }
}

However, currently this is not the case and the configuration does not have any effect.