Fix issue returning arrays from cache.modify modifier functions when the array contains a union type

[jerelmiller]

Fixes an issue with the following type:

cache.modify<{
  union: Array<
    | { __typename: "Type1"; a: string }
    | { __typename: "Type2"; b: string }
  >;
}>({
  fields: {
    union(field) {
      return field.filter((a) => a);
    },
  },
});

This PR also makes it possible to return a DeepPartial object for fields that are more complex types and don't query for the whole value:

cache.modify<{
  union: Array<
    | { __typename: "Type1"; a: string; c: { foo: string } }
    | { __typename: "Type2"; b: string; d: { bar: number } }
  >;
}>({
  fields: {
    union(field) {
      return [{ __typename: "Type1", a: "foo" }];
    },
  },
});

This makes it easier to pass a raw server GraphQL parent type to cache.modify.

Caveat: We don't recommend intentionally omitting fields like this example in real app code. This does a direct cache write which means that if data were available on c or d, that data would get removed from the cache. This is just to illustrate that this would previously create a TypeScript error but is now allowed since you may only be working with a subset of the field data at any given time.

[changeset-bot]

🦋 Changeset detected

Latest commit: d6e7b4f

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@apollo/client	Patch

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[jerelmiller]

/release:pr

[github-actions]

size-limit report 📦

Path	Size
dist/apollo-client.min.cjs	39.33 KB (0%)
import { ApolloClient, InMemoryCache, HttpLink } from "dist/main.cjs"	47.99 KB (0%)
import { ApolloClient, InMemoryCache, HttpLink } from "dist/main.cjs" (production)	45.57 KB (0%)
import { ApolloClient, InMemoryCache, HttpLink } from "dist/index.js"	34.4 KB (0%)
import { ApolloClient, InMemoryCache, HttpLink } from "dist/index.js" (production)	32.28 KB (0%)
import { ApolloProvider } from "dist/react/index.js"	1.26 KB (0%)
import { ApolloProvider } from "dist/react/index.js" (production)	1.24 KB (0%)
import { useQuery } from "dist/react/index.js"	5.21 KB (0%)
import { useQuery } from "dist/react/index.js" (production)	4.29 KB (0%)
import { useLazyQuery } from "dist/react/index.js"	5.69 KB (0%)
import { useLazyQuery } from "dist/react/index.js" (production)	4.77 KB (0%)
import { useMutation } from "dist/react/index.js"	3.62 KB (0%)
import { useMutation } from "dist/react/index.js" (production)	2.84 KB (0%)
import { useSubscription } from "dist/react/index.js"	4.41 KB (0%)
import { useSubscription } from "dist/react/index.js" (production)	3.46 KB (0%)
import { useSuspenseQuery } from "dist/react/index.js"	5.49 KB (0%)
import { useSuspenseQuery } from "dist/react/index.js" (production)	4.15 KB (0%)
import { useBackgroundQuery } from "dist/react/index.js"	4.99 KB (0%)
import { useBackgroundQuery } from "dist/react/index.js" (production)	3.64 KB (0%)
import { useLoadableQuery } from "dist/react/index.js"	5.07 KB (0%)
import { useLoadableQuery } from "dist/react/index.js" (production)	3.72 KB (0%)
import { useReadQuery } from "dist/react/index.js"	3.39 KB (0%)
import { useReadQuery } from "dist/react/index.js" (production)	3.33 KB (0%)
import { useFragment } from "dist/react/index.js"	2.32 KB (0%)
import { useFragment } from "dist/react/index.js" (production)	2.27 KB (0%)

[github-actions]

A new release has been made for this PR. You can install it with:

npm i @apollo/client@0.0.0-pr-11994-20240807160232

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[jerelmiller]

/release:pr

[github-actions]

A new release has been made for this PR. You can install it with:

npm i @apollo/client@0.0.0-pr-11994-20240807171545

[jerelmiller]

I think it eventually makes sense to also pass a DeepPartial as the value to the Modifier function since we can never guarantee you have data for the full type at any given time, only what has been written.

Doing this now might create a bit of churn though, so we might want to wait for a minor/major to make this change as fields that do property access with dot-notation might start complaining once we introduce this. I don't know what kind of impact that will have on our users, but might be good to avoid some anger for now.

[jerelmiller]

This is needed since the DeepPartial returns unknown on types that it doesn't know what to do with. StoreValue is a union of primitives and Reference so its unable to determine how to apply it.

[alessbell]

Discussed during our 1:1 - great catch! 🚀