fix(query-core): distinguish query keys differing only by a Date in partialMatchKey

[YESHYUNGSEOK]

🎯 Changes

Non-exact query-key matching (partialMatchKey) traverses objects structurally via Object.keys(b).every(...). For values whose data lives in internal slots rather than own-enumerable keys, Object.keys() is [], so the comparison is vacuously true. This makes two keys that differ only by a Date compare as equal — even though hashKey serializes Dates to distinct ISO strings and therefore stores them as separate cache entries.

As a result, non-exact operations (invalidateQueries, refetchQueries, removeQueries, cancelQueries, and createPersister matching) over-match unrelated sibling queries:

useQuery({ queryKey: ['report', { from: new Date('2020-01-01') }], queryFn }) // entry A
useQuery({ queryKey: ['report', { from: new Date('2021-06-25') }], queryFn }) // entry B (distinct hash)

// intends to invalidate only A, but invalidates BOTH A and B:
queryClient.invalidateQueries({ queryKey: ['report', { from: new Date('2020-01-01') }] })

Fix

partialMatchKey now only traverses plain objects/arrays structurally; any other object (e.g. Date) is compared the same way hashKey serializes it, keeping non-exact matching consistent with cache identity:

• Date keys that differ are no longer matched (the bug).
• Map/Set/RegExp keep matching, because hashKey also serializes them to {} — they already share a cache entry, so behavior there is unchanged and consistent.

Tests

Added regression tests to the partialMatchKey suite: distinct Date values must not match, equal Date values must match, and Map keys that hash equally keep matching.

✅ Checklist

• I have followed the steps in the Contributing guide.
• I have tested this code locally with pnpm run test:pr.

Verified locally on @tanstack/query-core: vitest run → 24 files / 548 tests pass, no type errors; eslint ./src → no new warnings on changed files. The full test:pr nx pipeline was not run.

🚀 Release Impact

• This change affects published code, and I have generated a changeset (patch for @tanstack/query-core).
• This change is docs/CI/dev-only (no release).

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes
  • Improved non-exact query key matching so keys with different Date values no longer incorrectly match.
  • Kept matching consistent for non-plain objects, including cases like Map, when their serialized values are the same.
  • Added test coverage for Date and other hash-equivalent object matching behavior.

[coderabbitai]

📝 Walkthrough

Walkthrough

partialMatchKey now uses recursive matching only for plain arrays and plain objects, and hash-based comparison for other object values. New tests cover differing and equal Date values plus hash-equivalent Map values. A changeset records the query-core fix.

Changes

partialMatchKey matching update

Layer / File(s)	Summary
Hash fallback for non-plain objects packages/query-core/src/utils.ts, packages/query-core/src/__tests__/utils.test.tsx, .changeset/spicy-dates-match.md	partialMatchKey now recurses only through plain arrays and plain objects, falls back to hashKey for other objects, and adds Date and Map test coverage with a changeset entry.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

A bunny tapped the query tree,
For Dates and Maps, “match fair,” said he.
He twitched his nose, then gave a hop,
“Hash on the odd ones, recursive on the plop!”
🐇✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title is concise and accurately describes the main change to partialMatchKey handling for Date-based query keys.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description check	✅ Passed	The PR description follows the required template and includes the change summary, checklist, and release impact details.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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