Union type field in an un-keyable entity gets wrong typename from the union

[gjorgi-krenkov]

So I have a fragment in this kind of style:

fragment fullOption on Option {
  selectId
  type
  options {
    ... on NumberArray {
      values
    }
    ... on CustomNumberArray {
      id
      name
      values
    }
  }
}

All of the Option, NumberArray and CustomNumberArray are un-keyable entities(considering the CustomNumberArray as keyable didn't fix the issue).

Invalidating the Option field is obviously overcoming this issue in the context of Mutations, but I have this problem occurring with the Queries where even though the API data has the correct typenames for the respective options, the URQL Cache client messes that data and there is an Option that is NumberArray but it later gets CustomNumberArray typename.

What's additionally weird isn't reproducible in a different environment.

Anyone has met with something similar?

[kitten]

I'm not fully sure I understand all of what you're saying and what issue this causes, however, importantly values here is present on NumberArray and on CustomNumberArray. What this means is that during a query Graphcache will find that NumberArray will also match when the type is actually a CustomNumberArray. That's because of heuristic fragment matching.

Currently, the only way to fix this is to either rename the fields so they don't conflict, or to add schema information to Graphcache. I was considering adding some kind of alternative for unions at least, but the gist of the issue here is that, structurally, the smaller of the fragments will heuristically match.

[gjorgi-krenkov]

Hi @kitten ,

The issue is the other way around, the type is NumberArray, but Graphcache considers it as a CustomNumberArray, and yes we do have codegen instrospected schema provided to Graphcache.

Need to take a look though whether renaming might help in our scenario. Also one crucial thing is that NumberArray doesn't contain neither of id and name so it doesn't make sense to match that data as a CustomNumberArray.

Also in the devtools, all of the NumberArray elements show up with an id and name value of undefined.