Is there a way to provide type mapping for entire array types?

[seeruk]

Where I work we use gRPC internally. When a repeated ProtoBuf field is sent over gRPC, there is no difference between a nil value and an empty value, so it reaches the server as nil (IIRC) and there's no way to discern whether the user supplied nil or an empty value. Of course, this distinction can be useful, if for example you're choosing whether to update something based on the presence of a value (e.g. set it to empty, vs. leave it alone in this case).

To work around this issue with gRPC and ProtoBuf, we made some wrapper types. For example:

syntax = "proto3";
package null;
message Strings {
  repeated string value = 1;
  bool valid = 2;
}

GraphQL doesn't have this problem - there is a difference between a null array, and an empty array. I've already plumbed this in using a resolver for this field. In this GraphQL service we're building, we're trying to minimise the amount of manual mapping we're having to do, and so far this is the only thing we've having to manually map with a resolver.

So I'm wondering, can I add some sort of configuration to the GraphQL field, or to the gqlgen.yaml file which will allow me to provide another type for [String!] to map onto as a whole. We do already map the elements onto similar null.String values just fine, but the entire array needs to be able to map to one of these null.Strings types instead.