[Schema Inaccuracy] Repository Advisory's author and publisher fields

[aj-foster]

Schema Inaccuracy

Currently, the #/components/schemas/repository-advisory schema has two fields with interesting types:

        author:
          readOnly: true
          description: The author of the advisory.
          allOf:
          - "$ref": "#/components/schemas/simple-user"
          type:
          - 'null'
        publisher:
          readOnly: true
          description: The publisher of the advisory.
          allOf:
          - "$ref": "#/components/schemas/simple-user"
          type:
          - 'null'

This appears to be somewhat contradictory, though it's always possible I'm misunderstanding the intent and the spec. The impact is that I'm currently unable to generate client code using a custom code generator (which, of course, might be wrong).

Expected

I believe the contents of the allOf property should be part of type, creating a nullable union:

        author:
          readOnly: true
          description: The author of the advisory.
          type:
          - "$ref": "#/components/schemas/simple-user"
          - 'null'
        publisher:
          readOnly: true
          description: The publisher of the advisory.
          type:
          - "$ref": "#/components/schemas/simple-user"
          - 'null'

Reproduction Steps

This issue arose while generating code from the description, so no API endpoint calls are involved. The code generator is language-specific, so it's unlikely to be useful during reproduction.