fix: apply query variable defaults when undefined is passed explicitly by atharv-sys32 · Pull Request #13364 · apollographql/apollo-client

atharv-sys32 · 2026-07-28T18:04:28Z

Summary by CodeRabbit

Bug Fixes
- Corrected GraphQL variable handling when variables are explicitly set to undefined.
- Query-defined default values are now applied correctly, ensuring conditional fields such as those controlled by @include return the expected results.

@Skip

When query variables like { show: undefined } are passed, the cache's diffQueryAgainstStore would overwrite GraphQL-specified default values with undefined by spreading the user-provided variables directly. This caused @include/@Skip directives to fail with 'Invalid variable referenced' errors. Filter out undefined values before merging with defaults, matching the behavior already implemented in QueryManager.getVariables. Fixes apollographql#13345

changeset-bot · 2026-07-28T18:04:31Z

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Latest commit: ecd2e19

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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apollo-librarian · 2026-07-28T18:04:31Z

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📝 Walkthrough

Walkthrough

The cache reader now removes explicitly undefined variables before merging query defaults. A test verifies that an undefined variable uses its default value when evaluating an @include directive.

Changes

Undefined variable default handling

Layer / File(s)	Summary
Cache reader variable normalization and validation `src/cache/inmemory/readFromStore.ts`, `src/cache/inmemory/__tests__/readFromStore.ts`	`diffQueryAgainstStore` filters undefined variables before applying query defaults, and a test confirms the conditional field is omitted when the default is `false`.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

apollographql/apollo-client#13362: Updates the same cache reader path and test behavior for undefined variables.

Suggested reviewers: benjamn

Poem

I’m a bunny with variables, undefined in my paw,
The cache finds the default and follows its law.
The hidden field stays tucked away,
While id hops out to play.
Clean defaults bring a bright new day!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly matches the main fix: ignoring explicit undefined variables so query defaults apply.
Linked Issues check	✅ Passed	The code and test directly address issue `#13345` by filtering undefined variables and letting the query default value apply.
Out of Scope Changes check	✅ Passed	The change set stays focused on variable default handling and the supporting regression test, with no clear unrelated additions.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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jerelmiller

Thanks for the submission! I had a couple small points of feedback. Before we merge, can you also make sure this PR has a changeset? Otherwise this won't end up in the changelog. Thanks!

jerelmiller · 2026-07-28T20:47:34Z

+    const rawVariables = variables ?? {};
    variables = {
      ...getDefaultValues(getQueryDefinition(query)),
-      ...variables!,
+      ...Object.fromEntries(
+        Object.entries(rawVariables).filter(([, v]) => v !== undefined)
+      ),
    };


Rather than spreading variables, then spreading it again (with a filter applied), lets instead use the compact utility which merges objects except undefined values.

Suggested change

const rawVariables = variables ?? {};

variables = {

...getDefaultValues(getQueryDefinition(query)),

...variables!,

...Object.fromEntries(

Object.entries(rawVariables).filter(([, v]) => v !== undefined)

),

};

variables = compact(

getDefaultValues(getQueryDefinition(query)),

variables

);

jerelmiller · 2026-07-28T20:55:20Z

    });
  });

+  it("applies defaults when variable is explicitly undefined", () => {


Great test! Can we also verify it correctly uses defaults if show is omitted altogether as well? I don't think we have any other test in this suite that verifies that. That just makes sure we don't add any regressions there as well 🙂

I think the test doesn't work at all since the field has no value in the store. So even if show: true was used (or defaulted), the query would return only { id: "abcd" } as the result?

@ab-pm the readQueryFromStore helper that this test uses sets returnPartialData: false by default so if @include really weren't evaluated, the result would be null instead of { id: "abcd" } due to the result being a partial result. I think its ok 🙂

atharv-sys32 · 2026-07-29T04:48:07Z

Hey @jerelmiller , I've addressed all your feedback:

Replaced the manual spread/filter with the compact() utility
Added a test for entirely omitted variables as a regression guard
Added a changeset for the changelog

Would appreciate if you could take another look when you get a chance. Thanks!

jerelmiller

Thanks again for the contribution! I'll get this out in the next patch.

pkg-pr-new · 2026-07-29T23:24:56Z

npm i https://pkg.pr.new/@apollo/client@13364

commit: ecd2e19

atharv-sys32 · 2026-07-30T08:17:17Z

Hey @jerelmiller, thanks for the quick merge on this one! Really appreciate it.

If you have a moment, could you also take a look at #13365? It's the docs-only unique-names anchor fix - small change and already reviewed. Thanks!

@atharv-sys32

This PR was opened by the [Changesets release](https://github.com/changesets/action) GitHub action. When you're ready to do a release, you can merge this and the packages will be published to npm automatically. If you're not ready to do a release yet, that's fine, whenever you add more changesets to main, this PR will be updated. # Releases ## @apollo/client@4.2.9 ### Patch Changes - [#13364](#13364) [`2f383e7`](2f383e7) Thanks [@atharv-sys32](https://github.com/atharv-sys32)! - Fix a bug where GraphQL variable default values were not applied during cache reads when variables with defaults were explicitly set to `undefined`. This caused `@include`/`@skip` directives to throw "Invalid variable referenced" errors when the variable was passed as `undefined` instead of being omitted entirely. - [#13367](#13367) [`2b39cc8`](2b39cc8) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Fix an issue where some `@export` queries would not react to cache updates when the fields keyed by exported variables were updated. Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

atharv-sys32 mentioned this pull request Jul 28, 2026

Add unique-names anchor to fragments docs #13336

Closed

jerelmiller requested changes Jul 28, 2026

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fix: use compact utility, add tests for omitted variables, add changeset

60ae980

atharv-sys32 requested a review from jerelmiller July 29, 2026 04:48

jerelmiller reviewed Jul 29, 2026

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Comment thread .changeset/pink-shoes-cheer.md Outdated

jerelmiller added 2 commits July 29, 2026 17:19

Update .changeset/pink-shoes-cheer.md

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jerelmiller approved these changes Jul 29, 2026

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jerelmiller enabled auto-merge (squash) July 29, 2026 23:22

jerelmiller merged commit 2f383e7 into apollographql:main Jul 29, 2026
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github-actions Bot mentioned this pull request Jul 29, 2026

Version Packages #13370

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