fix(solid-query): subscribe to the new observer when the queryClient changes

[taekop]

🎯 Changes

Fixes #11106.

When the queryClient passed to useQuery changes, useBaseQuery subscribed before setting the new observer, so the subscription attached to the old observer and the new client's entry never fetched. This swaps the two lines.

Tests: the "should refetch query when queryClient changes" test now asserts the new client's data and that the old client was not refetched. In solid-query-persist-client, "should be able to persist into multiple clients" no longer pins states to length 3, because the new observer subscribing emits extra intermediate states. It now checks the first state, that the hydrated/fetching state appears, and that the last state is queryFn2's data. The call-count assertions are unchanged.

I used an AI assistant (Claude Code) while working on this.

✅ Checklist

• I have followed the steps in the Contributing guide.
• I have tested code changes locally with pnpm run test:pr, or these tests do not apply to this pull request. (Not run. I ran vitest, eslint and tsc for solid-query and solid-query-persist-client instead, plus prettier on the changed files.)
• I have followed the AI contribution policy and fully understand the code in this pull request, including any code generated with AI assistance.

🚀 Release Impact

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

Summary by CodeRabbit

• Bug Fixes
  • Fixed an issue where changing the query client could leave queries subscribed to the previous client. Queries now use the new client and receive its fetched data.
  • Improved reliability when switching between clients while persisted query data is being restored.

[changeset-bot]

🦋 Changeset detected

Latest commit: e26a91b

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

This PR includes changesets to release 24 packages

Name	Type
@tanstack/solid-query	Patch
@tanstack/solid-query-devtools	Patch
@tanstack/solid-query-persist-client	Patch
@tanstack/angular-query-experimental	Patch
@tanstack/eslint-plugin-query	Patch
@tanstack/preact-query-devtools	Patch
@tanstack/preact-query-persist-client	Patch
@tanstack/preact-query	Patch
@tanstack/query-async-storage-persister	Patch
@tanstack/query-broadcast-client-experimental	Patch
@tanstack/query-core	Patch
@tanstack/query-devtools	Patch
@tanstack/query-persist-client-core	Patch
@tanstack/query-sync-storage-persister	Patch
@tanstack/react-query-devtools	Patch
@tanstack/react-query-next-experimental	Patch
@tanstack/react-query-persist-client	Patch
@tanstack/react-query	Patch
@tanstack/vue-query	Patch
@tanstack/lit-query	Patch
@tanstack/svelte-query	Patch
@tanstack/svelte-query-devtools	Patch
@tanstack/vue-query-devtools	Patch
@tanstack/svelte-query-persist-client	Patch

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ℹ️ Recent review info

⚙️ Run configuration

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• Plan: Advanced
• Run ID: 1cff46a5-970b-469d-ac51-0638870d4f06

📥 Commits

Reviewing files that changed from the base of the PR and between d169ee8 and e26a91b.

📒 Files selected for processing (4)

• .changeset/solid-query-client-switch.md
• packages/solid-query-persist-client/src/__tests__/PersistQueryClientProvider.test.tsx
• packages/solid-query/src/__tests__/useQuery.test.tsx
• packages/solid-query/src/useBaseQuery.ts

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📝 Walkthrough

Walkthrough

When the query client changes, useBaseQuery now installs the new observer before creating its subscription. Tests verify the resulting cache contents and allow intermediate states. A patch changeset records the fix.

Changes

Solid Query client switching

Layer / File(s)	Summary
Rebind the observer subscription packages/solid-query/src/useBaseQuery.ts, packages/solid-query/src/__tests__/useQuery.test.tsx, packages/solid-query-persist-client/src/__tests__/PersistQueryClientProvider.test.tsx, .changeset/solid-query-client-switch.md	useBaseQuery installs the new observer before creating its subscription. Tests check the cached data and update count, and allow intermediate states during client switching. A patch changeset records the fix.

Priority: ➖ Normal

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

Change: Bug fix · Severity of issue fixed: Medium

Suggested reviewers: sukvvon

Merge Risk: ⚪ Minimal · up to e26a9

The client-switch fix directs the query result to the new client’s cache. No actionable merge-blocking risk remains in the reviewed changes.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main change: useQuery subscribes to the new observer when queryClient changes.
Description check	✅ Passed	The description includes the required Changes, Checklist, and Release Impact sections. It explains the fix and tests, records that pnpm run test:pr was not run, and confirms that a changeset was gen…
Linked Issues check	✅ Passed	Issue #11106 requires the hook to subscribe to the new observer and place the query result in the new client's cache after a client switch. useBaseQuery.ts now calls setObserver(newObserver) befor…
Out of Scope Changes check	✅ Passed	All changes support issue #11106. The persistence test accepts intermediate observer states introduced by the new subscription while still checking the meaningful states and fetch outcome. The changes…
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 3 files. (1 skipped: 1 …

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