graphql-directive | Use custom directives in your GraphQL schema and queries | GraphQL library

The issue here is that the referenced implementation throws an error when the wrapping resolver does not find any required roles (neither for the object type nor the field in question) in these lines of code.

The logic is that as you use the directive for some field of an object type, you also need to provide a requirement for the type itself. In my opinion this logic isn't too bad and is as the code comment suggests to be on the safe side. The author of that implementation probably focused on usage of the directive for actual data types, not for queries or mutations.

Let me be even a little more specific: What you and I do (as I am trying to accomplish the same thing as you today), when using the directive for one or several queries/mutations is actually applying the directive on the fields of the schema types Query and Mutation. So if we don't want a minimum requirement for all queries and/or mutations of our schema, the code should not throw an error in that condition I linked above, but it should call the wrapped resolver just as if the requirements were met (because there are none).

Example: