Type policies broken starting 3.3.0

[Banou26]

Intended outcome:
Trying to query a typePolicy field should work

Actual outcome:
The query is always loading

How to reproduce the issue:
Try to query a typePolicy field, e.g

export default new InMemoryCache({
  typePolicies: {
    Query: {
      fields: {
        foo: () => 'foo'
      }
    }
  }
})


  // .... in a component
  const { data, ...rest } = useQuery(gql`query Foo { foo @client }`)
  // rest.loading is always true and data is always undefined

Versions
apollo-client ^3.3.0 / ^3.3.6 / ^3.4 beta

[Banou26]

@Banou26 : did you find any work arounds for this issue? until the fix come in?

@pramodshri-tgsys I downgraded my ApolloClient version to 3.2.8.
If you found any real workarounds I'd like to know too :)

[pramod-knidal]

In my case, there was an error in the code but no errors were reported. I didn't have a return statement at the end of the function code.

[benjamn]

@Banou26 This would be pretty worrisome if true, but it does not seem to be reproducing for me.

The symptoms are consistent with there not being any field policy defined for the Query.foo field. Can you double-check that your actual field name is spelled the same everywhere, and that the InMemoryCache object you're configuring and exporting is the same cache that gets used by the ApolloClient behind the useQuery call?

Of course, a reproduction would be even more useful.

[Banou26]

@benjamn here is the smallest repro I managed to get.

import { InMemoryCache, ApolloClient, gql } from '@apollo/client'

const cache = new InMemoryCache({
  typePolicies: {
    Query: {
      fields: {
        foo: () => 'foo'
      }
    }
  }
})

cache.policies.addTypePolicies({
  Query: {
    // If you comment the fields property, the logs will return 'foo'
    fields: {
      settings: () => {}
    }
  }
})

const client = new ApolloClient({
  cache
})

console.log(client.query({ query: gql` { foo } ` }))

// results of commented typePolicies fields property

// Promise {<pending>}
// __proto__: Promise
// [[PromiseState]]: "fulfilled"
// [[PromiseResult]]: Object
// data: {foo: "foo"}
// loading: false
// networkStatus: 7



// results of uncommented typePolicies fields property

// Promise {<pending>}
// __proto__: Promise
// [[PromiseState]]: "fulfilled"
// [[PromiseResult]]: undefined

It seems like it's due to the use of cache.policies.addTypePolicies, it seems to "overwrite" instead of "add", if I add foo back into the addTypePolicies object, it does indeed still work fine.

This is new behavior starting 3.3.0, in 3.2.x it worked fine.

[Remownz]

I can confirm. We also use multiple cache.policies.addTypePolicies. We also have to downgrade to 3.2.x.

[Banou26]

@benjamn Any updates on this ?
Still a bug on 3.3.15 which prevents anyone using cache.policies.addTypePolicies to upgrade above 3.2.