"Cannot read property 'type' of undefined" with multiple inheritance levels

[TheReincarnator]

When generating TypeScript types from the following schema , I get "Cannot read property 'type' of undefined":

  type ApplicationForm {
    items: [Item!]!
  }

  interface Item {
    id: ID!
  }
  interface Field {
    id: ID!
    label: String!
  }

  type RichTextItem implements Item {
    id: ID!
    content: String!
  }
  type TextField implements Item & Field {
    id: ID!
    label: String!
  }

I think the code generator is confused by using both types that implement "Item" and "Item & Field".

The problem seems to be in pre-resolve-types.ts, in both transformPrimitiveFields and transformAliasesPrimitiveFields. At that point, the schemaType contains fields that fields do not.

A work-around, maybe even the solution, is to filter all schemaType fields before mapping them:

fields.filter(field => schemaType.getFields()[field]).map(...)

[dotansimha]

@TheReincarnator can you please share a live reproduction of that issue?
Thank you!

[ardatan]

Closing this issue for now. Feel free to create a new issue with a minimal reproduction if it still persists.

[n1ru4l]

@TheReincarnator Hey, can you please share the operation that caused this issue? We have a potential PR that solves this issue, however, @mvestergaard is not able to produce a failing test (See #6874).