Fix: Solid query `useIsMutating` throwing an error and `useMutationState` infinite loop

[dev-rb]

• Fixes an infinite loop in useMutationState caused by reading and writing to results in an effect.
• Fixes useIsMutating throwing a reading properties of undefined error caused by reading isMutating of client which could be undefined in the case of some SSR environments/setups. This fix also makes it consistent with useMutationState where the subscription is created inside of an effect

Summary by CodeRabbit

• Bug Fixes

  • More reliable mutation status updates that react correctly to changing inputs.
  • Proper cleanup of subscriptions on component unmount or re-run, reducing potential leaks.
  • Prevented stale data by resubscribing when relevant reactive sources change.

• Performance

  • Reduced unnecessary recalculations and renders by avoiding tracked reads during comparisons.
  • More efficient equality checks to minimize redundant updates.

• Refactor

  • Improved reactivity management without altering the public API.

[coderabbitai[bot]]

Walkthrough

The subscription to the mutation cache in useIsMutating was moved into a Solid createEffect with onCleanup for lifecycle management. In useMutationState, untrack was introduced to read the result signal untracked within the subscription callback, adjusting equality checks accordingly. Public APIs remain unchanged.

Changes

Cohort / File(s)	Summary of edits
Reactive subscription lifecycle update packages/solid-query/src/useIsMutating.ts	Wrapped mutation cache subscription in Solid createEffect; added onCleanup to dispose subscriptions; effect depends on mutationCache(), client(), and filters?.() to resubscribe on changes; imported createEffect.
Untracked result handling in mutation state packages/solid-query/src/useMutationState.ts	Imported untrack; inside subscription callback, read result via untrack(result) to avoid reactive tracking; used this untracked value in replaceEqualDeep and equality check before setting nextResult.

Sequence Diagram(s)

sequenceDiagram
  autonumber
  participant C as Component
  participant U as useIsMutating
  participant E as Solid createEffect
  participant MC as MutationCache
  participant CL as onCleanup

  C->>U: call useIsMutating(filters)
  U->>E: createEffect(() => { ... })
  E->>MC: subscribe(onEvent)
  Note over E,MC: Effect reads mutationCache(), client(), filters?.()
  MC-->>E: mutation events
  E->>U: set mutations count via client().isMutating(...)
  CL-->>MC: unsubscribe on cleanup/re-run
  Note over E: Re-runs and re-subscribes when dependencies change

sequenceDiagram
  autonumber
  participant MC as MutationCache
  participant S as Subscription Callback
  participant R as result signal
  participant UT as untrack(...)
  participant EQ as replaceEqualDeep + compare
  participant ST as setState

  MC-->>S: notify on mutation change
  S->>UT: _result = untrack(R)
  S->>EQ: next = replaceEqualDeep(prev, _result)
  alt _result !== next
    S->>ST: update state to next
  else
    S-->>S: no update
  end

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Suggested reviewers

• TkDodo

Pre-merge checks (2 passed, 1 warning)

❌ 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%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title Check	✅ Passed	The title concisely and accurately summarizes the PR’s primary intent by naming the two affected Solid Query hooks and the specific bugs being fixed, and it aligns with the PR description and file-level changes so a reviewer can quickly understand the main purpose.

Poem

A whisker twitch, a subtle tweak—
Subscriptions nest, then softly sleep.
Untracked footsteps, quiet, neat,
Signals hum with lighter feet.
In Solid burrows, caches sing—
Hop hop! Another tidy spring. 🐇✨

[!TIP]

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[TkDodo]

please add a test that fails on main but works with your changes. thanks 🙏

@ardeora FYI

[changeset-bot[bot]]

⚠️ No Changeset found

Latest commit: a3feb81ca2302b630a9536a52f2c69d1ea7f3b33

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