bug: cycle between steps causes an infinite loop

[kamilkisiela]

supergraph

schema
  @link(url: "https://specs.apollo.dev/link/v1.0")
  @link(url: "https://specs.apollo.dev/join/v0.3", for: EXECUTION) {
  query: Query
}

directive @join__enumValue(graph: join__Graph!) repeatable on ENUM_VALUE

directive @join__field(
  graph: join__Graph
  requires: join__FieldSet
  provides: join__FieldSet
  type: String
  external: Boolean
  override: String
  usedOverridden: Boolean
) repeatable on FIELD_DEFINITION | INPUT_FIELD_DEFINITION

directive @join__graph(name: String!, url: String!) on ENUM_VALUE

directive @join__implements(
  graph: join__Graph!
  interface: String!
) repeatable on OBJECT | INTERFACE

directive @join__type(
  graph: join__Graph!
  key: join__FieldSet
  extension: Boolean! = false
  resolvable: Boolean! = true
  isInterfaceObject: Boolean! = false
) repeatable on OBJECT | INTERFACE | UNION | ENUM | INPUT_OBJECT | SCALAR

directive @join__unionMember(
  graph: join__Graph!
  member: String!
) repeatable on UNION

directive @link(
  url: String
  as: String
  for: link__Purpose
  import: [link__Import]
) repeatable on SCHEMA

type AnonymousReview @join__type(graph: A) {
  anonymous_body: String!
  product: Product
}

scalar join__FieldSet

enum join__Graph {
  A @join__graph(name: "a", url: "http://localhost:4200/union-overfetching/a")
  B @join__graph(name: "b", url: "http://localhost:4200/union-overfetching/b")
  C @join__graph(name: "c", url: "http://localhost:4200/union-overfetching/c")
  D @join__graph(name: "d", url: "http://localhost:4200/union-overfetching/d")
}

scalar link__Import

enum link__Purpose {
  """
  `SECURITY` features provide metadata necessary to securely resolve fields.
  """
  SECURITY

  """
  `EXECUTION` features provide metadata necessary for operation execution.
  """
  EXECUTION
}

type Product
  @join__type(graph: A, key: "newId")
  @join__type(graph: B, key: "newId")
  @join__type(graph: B, key: "oldId")
  @join__type(graph: C, key: "oldId")
  @join__type(graph: D, key: "oldId") {
  newId: ID! @join__field(graph: A) @join__field(graph: B)
  oldId: ID!
    @join__field(graph: B)
    @join__field(graph: C)
    @join__field(graph: D)
  b: String! @join__field(graph: B)
  c: String! @join__field(graph: C)
  d: String! @join__field(graph: D)
}

type Query
  @join__type(graph: A)
  @join__type(graph: B)
  @join__type(graph: C)
  @join__type(graph: D) {
  viewer: Viewer! @join__field(graph: A)
}

union Review
  @join__type(graph: A)
  @join__unionMember(graph: A, member: "AnonymousReview")
  @join__unionMember(graph: A, member: "UserReview") =
  | AnonymousReview
  | UserReview

type UserReview @join__type(graph: A) {
  user_body: String!
  product: Product
}

type Viewer @join__type(graph: A) {
  review: Review
}

query

{
  viewer {
    review {
      ... on AnonymousReview {
        __typename
        anonymous_body
        product {
          b
        }
      }
      ... on UserReview {
        __typename
        user_body
        product {
          c
          d
        }
      }
    }
  }
}

[linear]

GWRS-94 bug: cycle between steps causes an infinite loop

+++ supergraph

schema
  @link(url: "https://specs.apollo.dev/link/v1.0")
  @link(url: "https://specs.apollo.dev/join/v0.3", for: EXECUTION) {
  query: Query
}

directive @join__enumValue(graph: join__Graph!) repeatable on ENUM_VALUE

directive @join__field(
  graph: join__Graph
  requires: join__FieldSet
  provides: join__FieldSet
  type: String
  external: Boolean
  override: String
  usedOverridden: Boolean
) repeatable on FIELD_DEFINITION | INPUT_FIELD_DEFINITION

directive @join__graph(name: String!, url: String!) on ENUM_VALUE

directive @join__implements(
  graph: join__Graph!
  interface: String!
) repeatable on OBJECT | INTERFACE

directive @join__type(
  graph: join__Graph!
  key: join__FieldSet
  extension: Boolean! = false
  resolvable: Boolean! = true
  isInterfaceObject: Boolean! = false
) repeatable on OBJECT | INTERFACE | UNION | ENUM | INPUT_OBJECT | SCALAR

directive @join__unionMember(
  graph: join__Graph!
  member: String!
) repeatable on UNION

directive @link(
  url: String
  as: String
  for: link__Purpose
  import: [link__Import]
) repeatable on SCHEMA

type AnonymousReview @join__type(graph: A) {
  anonymous_body: String!
  product: Product
}

scalar join__FieldSet

enum join__Graph {
  A @join__graph(name: "a", url: "http://localhost:4200/union-overfetching/a")
  B @join__graph(name: "b", url: "http://localhost:4200/union-overfetching/b")
  C @join__graph(name: "c", url: "http://localhost:4200/union-overfetching/c")
  D @join__graph(name: "d", url: "http://localhost:4200/union-overfetching/d")
}

scalar link__Import

enum link__Purpose {
  """
  `SECURITY` features provide metadata necessary to securely resolve fields.
  """
  SECURITY

  """
  `EXECUTION` features provide metadata necessary for operation execution.
  """
  EXECUTION
}

type Product
  @join__type(graph: A, key: "newId")
  @join__type(graph: B, key: "newId")
  @join__type(graph: B, key: "oldId")
  @join__type(graph: C, key: "oldId")
  @join__type(graph: D, key: "oldId") {
  newId: ID! @join__field(graph: A) @join__field(graph: B)
  oldId: ID!
    @join__field(graph: B)
    @join__field(graph: C)
    @join__field(graph: D)
  b: String! @join__field(graph: B)
  c: String! @join__field(graph: C)
  d: String! @join__field(graph: D)
}

type Query
  @join__type(graph: A)
  @join__type(graph: B)
  @join__type(graph: C)
  @join__type(graph: D) {
  viewer: Viewer! @join__field(graph: A)
}

union Review
  @join__type(graph: A)
  @join__unionMember(graph: A, member: "AnonymousReview")
  @join__unionMember(graph: A, member: "UserReview") =
  | AnonymousReview
  | UserReview

type UserReview @join__type(graph: A) {
  user_body: String!
  product: Product
}

type Viewer @join__type(graph: A) {
  review: Review
}

+++

+++ query

{
  viewer {
    review {
      ... on AnonymousReview {
        __typename
        anonymous_body
        product {
          b
        }
      }
      ... on UserReview {
        __typename
        user_body
        product {
          c
          d
        }
      }
    }
  }
}

+++