Resolving Nullable vs. Required in OAS

[lilyren-homex]

In my source OAS file (openapi 3.0.0), I have an output object defined like this:

"ReservationOutput": {
        "properties": {
          "id": {
            "type": "string"
          },
          "client_id": {
            "type": "string"
          },
          "notes": {
            "type": "string",
            "nullable": true
          }
        },
        "required": [
          "id",
          "client_id",
          "notes"
        ],
        "type": "object",
        "additionalProperties": false
      },

When it goes through Mesh, even though notes is declared as nullable, it still shows up as a non-nullable field in the final query. When the upstream service sends back the ReservationOutput with "notes": null, it would cause an error.

I have tried to transform the ReservationOutput to something like ReservationOutputNullable, so that the notes field type is changed from String! to String. However when being resolved it would still cause error Cannot return null for non-nullable field. When removing notes from the query, the query is successful.

Is there a reason why Mesh favours required over nullable when choosing if a field is nullable? Is there another work-around for this?

[ardatan]

I think we have missing support for nullable property.
#2328 is supposed to fix it
Could you try the alpha version below?
@graphql-mesh/openapi@0.16.11-alpha-4395c6420.0

[ardatan]

Available in @graphql-mesh/openapi@0.16.11