Hasura queries that include a fragment on a union type do not work

[arcticmatt]

Version Information

Server Version: 2.7.0, 2.13.0

Environment

Tried on Cloud and locally (using Docker)

What is the current behaviour?

This is what happens when I hit Hasura (which sits in front of a remote schema)

The response is missing goalAmount

What is the expected behaviour?

This is what happens when I hit the remote schema directly (same exact query)

The response returns goalAmount as expected

How to reproduce the issue?

See queries in screenshots above

Any possible solutions/workarounds you're aware of?

The query works if you don't have a fragment directly on a union type

Keywords

union,fragment

[arcticmatt]

@adas98012 any update on this?

[ben-white-openx]

@arcticmatt I might be running into the same issue, curious if you can reproduce this.

I can run a query that references the members of the union, with or without fragment syntax (my union type here is union UnionFoo = FooStandalone | FooShadow):

{
  Foo(limit: 10) {
    __typename
    ...on FooStandalone { id name }
    ...on FooShadow { id name }
  }
}

or

{
  Foo(limit: 10) {
    __typename
    ...FooStandaloneFragment
    ...FooShadowFragment
  }
}
fragment FooStandaloneFragment on FooStandalone { id name }
fragment FooShadowFragment on FooShadow { id name }

Remote GraphQL service receives:

query: 'query  { Foo(limit: 10) { __typename  ... on FooShadow{ id  name  } ... on FooStandalone{ id  name  } } }'

So far, so good.

However I get the same as you if I reference the union type itself - the fields are omitted from the delegated query:

{
  Foo(limit: 10) {
    __typename
    ...on UnionFoo {
      ... on FooStandalone {
        id
        name
      }
      ... on FooShadow {
        id
        name
      }
    }
  }
}

or

{
  Foo(limit: 10) {
    __typename
    ...UnionFooFragment
  }
}

fragment UnionFooFragment on UnionFoo {
  ...FooStandaloneFragment
  ...FooShadowFragment
}
fragment FooStandaloneFragment on FooStandalone { id name }
fragment FooShadowFragment on FooShadow { id name }

Remote GraphQL service receives:

query: 'query  { Foo(limit: 10) { __typename  } }' }

So this is happening for me whenever a union type is referenced in the selection set, not just via a fragment.

(Incidentally I'm generating these queries from an AST with print - so I can't enforce the inline syntax.)

We're on Hasura server v2.15.2.