Cache with {addTypename:false} causes query to return empty data when fragments are used

I have a simple query described in a .gql file:

fragment thingBody on Thing {
    id
    name
    description
}

query things {
    things {
        ...thingBody
    }
}

I have a client with this configuration:

const client = new ApolloClient ({
  new InMemoryCache({ addTypename: false}),
  new HttpLink({ uri: myURI}),
});

Intended outcome:

This query should return this data, which is identical to what’s returned when using the no-cache policy:

{
    things: [
      {
        id: '001',
        name: 'Thing1',
        description: 'This is a standard thing',
      },
      {
        id: '002',
        name: 'Thing2',
        description: 'This is a standard thing',
      },
      {
        id: '003',
        name: 'Thing3',
        description: 'This is a standard thing',
      },
    ]
}

Actual outcome:

{ things: [ {}, {}, {} ] }

How to reproduce the issue:

Configure a cache and client as above and use any query with a fragment.

Versions

Binaries: Node: 14.6.0 - /usr/local/bin/node npm: 6.14.7 - /usr/local/bin/npm npmPackages: @apollo/client: 3.1.4 => 3.1.4

[l-abels]

If I use the no-cache option or the old apollo-fetch module, the query “just works”. I was a little surprised that adding a cache could cause incorrect query results, I assumed it could be implemented in such a way that it did no harm. Thanks for the info, adapting to having __typename injected into everything won’t be a major issue for me.

[Ellosaur]

FYI for anyone finding the same issue disabling the cache is the only solution I’ve found. See this answer and dont forget to add back in { addTypename: false } to the “diasbled” InMemoryCache in order to avoid the error Introspection is not allowed. from the server.

Important: this seems to break our use of a paged query as below. I’ll update if I solve that issue as well const { data, error, loading, fetchMore } = useQuery(gql(query), { variables: { term, skipCount: 0 } });