[repro] synced data not appearing in derived collection during pending optimistic mutation (issue #1017) #1166

claude · 2026-01-20T09:19:58Z

Summary

Adds a reproduction test for issue #1017: Synced data does not appear in a derived (live query) collection while there is a pending optimistic mutation on that derived collection.

What the test asserts

The test validates that synced data from a source collection should appear in derived collections immediately, regardless of whether there are pending optimistic mutations.

Test flow:

Creates a source collection with controllable sync
Creates a derived collection via createLiveQueryCollection (simple passthrough)
Uses createOptimisticAction to insert an item with a pending mutation
While mutation is pending, syncs a NEW item into the source collection
Asserts both items should be visible in the derived collection

How to run

pnpm --filter "@tanstack/db" test -- tests/query/live-query-collection.test.ts -t "synced data visibility"

Observed failure

AssertionError: expected false to be true
 ❯ tests/query/live-query-collection.test.ts:1170:41
    expect(derived.has(`synced-1`)).toBe(true)

The synced item (synced-1) is invisible in the derived collection while the optimistic mutation is pending, confirming the bug.

… optimistic mutation (issue #1017) Adds a test that reproduces the bug where synced data from a source collection does not appear in a derived (live query) collection while there is a pending optimistic mutation. The test: 1. Creates a source collection with controllable sync 2. Creates a derived collection via createLiveQueryCollection 3. Uses createOptimisticAction to insert an item (mutation stays pending) 4. Syncs a new item into the source collection while mutation is pending 5. Asserts that both items should be visible in the derived collection Currently failing because synced data is invisible while optimistic mutations are pending. Co-Authored-By: Claude <noreply@anthropic.com>

changeset-bot · 2026-01-20T09:20:03Z

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Latest commit: 883f4e2

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pkg-pr-new · 2026-01-20T09:21:44Z

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commit: 883f4e2

github-actions · 2026-01-20T09:22:22Z

Size Change: 0 B

Total Size: 90.8 kB

ℹ️ View Unchanged

Filename	Size
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_{compressed-size-action::db-package-size}

github-actions · 2026-01-20T09:23:00Z

Size Change: 0 B

Total Size: 3.7 kB

ℹ️ View Unchanged

Filename	Size
`./packages/react-db/dist/esm/index.js`	225 B
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`./packages/react-db/dist/esm/useLiveQuery.js`	1.34 kB
`./packages/react-db/dist/esm/useLiveSuspenseQuery.js`	559 B
`./packages/react-db/dist/esm/usePacedMutations.js`	401 B

_{compressed-size-action::react-db-package-size}

This was referenced Jan 20, 2026

[fix] synced data not appearing in derived collection during pending optimistic mutation (issue #1017) #1167

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Synced data does not appear in a derived (live query) collection while there is a pending optimistic mutation. #1017

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[repro] synced data not appearing in derived collection during pending optimistic mutation (issue #1017) #1166

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[repro] synced data not appearing in derived collection during pending optimistic mutation (issue #1017) #1166

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[repro] synced data not appearing in derived collection during pending optimistic mutation (issue #1017) #1166

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claude bot commented Jan 20, 2026

Summary

What the test asserts

How to run

Observed failure

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