useFragment invalid return value in the case of null or undefined id in the from argument

[kouak]

Issue Description

When using useFragment, I'm expecting some sort of error or warning if I try to read an object with a null or undefined id.

useFragment<TData>({
  from: {
    __typename: 'Mail',
    id: null,
  },
  fragment,
  fragmentName: 'MyFragment',
});

// v3.8.8:  { complete: false, data: {}, missing: 'Dangling reference to missing Mail:null }
// v3.8.9: { complete: true, data: {} }

This also does not match the typescript return type of useFragment<TData>(); . When complete is true, data should be of type TData.

A workaround is to pass an empty string or false as id.

Link to Reproduction

https://codesandbox.io/p/devbox/recursing-tesla-4f6vt3

Reproduction Steps

Click on the Lookup a person by ID with an empty input.

This will pass null as from.id to useFragment.

@apollo/client version

3.8.9 and later

[phryneas]

That looks like a bug, thank you for the report and the reproduction!