Fix: Live query collections stuck in initialCommit status when source collections are preloaded after creation

[samwillis]

stacked on #390, fairly sure that it fixes #391

Problem

Live query collections were getting stuck in initialCommit status instead of transitioning to ready status when their source collections were preloaded after the live query collection was created. This caused issues where:

• Live queries would have the correct data but remain in initialCommit status
• Components relying on collection.status === 'ready' would not update properly
• The live query would only transition to ready when mutations/remote updates occurred

This matches the user report: "if I don't preload the collection before rendering, It won't update after being loaded. It'll only update, when some mutation/remote update happens"

Root Cause

The issue was in the markReady() method in packages/db/src/collection.ts. When a collection became ready for the first time, it would only emit an empty ready event if the collection was empty AND had change listeners:

// Before (problematic)
if (this.size === 0 && this.changeListeners.size > 0) {
  this.emitEmptyReadyEvent()
}

This condition was too restrictive. Live query collections that depend on source collections often have data but still need to emit the ready event to properly transition their status.

Solution

Changed the condition to emit the ready event whenever there are change listeners, regardless of collection size:

// After (fixed)
if (this.changeListeners.size > 0) {
  this.emitEmptyReadyEvent()
}

This ensures that any collection with active subscribers will properly emit the ready event when it transitions to ready status, allowing dependent live query collections to also transition to ready status.

Testing

Added a comprehensive test case that reproduces the exact scenario:

1. Creates a source collection with startSync: false
2. Creates a live query collection that depends on the source collection
3. Starts the live query's preload() promise before the source collection is ready
4. Preloads the source collection and triggers initial data load
5. Verifies that the live query properly transitions to ready status

The test uses explicit promise control instead of flaky timeouts to ensure reliable reproduction of the issue.

Impact

This fix ensures that live query collections properly transition to ready status when their source collections are preloaded after the live query is created, resolving the issue where components would not update properly until mutations occurred.

[changeset-bot]

🦋 Changeset detected

Latest commit: 8b6bfd8

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

This PR includes changesets to release 8 packages

Name	Type
@tanstack/db	Patch
@tanstack/electric-db-collection	Patch
@tanstack/query-db-collection	Patch
@tanstack/react-db	Patch
@tanstack/solid-db	Patch
@tanstack/svelte-db	Patch
@tanstack/trailbase-db-collection	Patch
@tanstack/vue-db	Patch

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commit: 8b6bfd8

[github-actions]

Size Change: -5 B (-0.01%)

Total Size: 58.5 kB

Filename	Size	Change
./packages/db/dist/esm/collection.js	9.87 kB	-5 B (-0.05%)

ℹ️ View Unchanged

Filename	Size
./packages/db/dist/esm/change-events.js	1.13 kB
./packages/db/dist/esm/deferred.js	230 B
./packages/db/dist/esm/errors.js	2.98 kB
./packages/db/dist/esm/index.js	1.51 kB
./packages/db/dist/esm/indexes/auto-index.js	689 B
./packages/db/dist/esm/indexes/base-index.js	605 B
./packages/db/dist/esm/indexes/btree-index.js	1.47 kB
./packages/db/dist/esm/indexes/lazy-index.js	1.25 kB
./packages/db/dist/esm/local-only.js	827 B
./packages/db/dist/esm/local-storage.js	2.03 kB
./packages/db/dist/esm/optimistic-action.js	294 B
./packages/db/dist/esm/proxy.js	4.19 kB
./packages/db/dist/esm/query/builder/functions.js	575 B
./packages/db/dist/esm/query/builder/index.js	3.79 kB
./packages/db/dist/esm/query/builder/ref-proxy.js	890 B
./packages/db/dist/esm/query/compiler/evaluators.js	1.48 kB
./packages/db/dist/esm/query/compiler/expressions.js	631 B
./packages/db/dist/esm/query/compiler/group-by.js	2.03 kB
./packages/db/dist/esm/query/compiler/index.js	1.74 kB
./packages/db/dist/esm/query/compiler/joins.js	1.56 kB
./packages/db/dist/esm/query/compiler/order-by.js	677 B
./packages/db/dist/esm/query/compiler/select.js	655 B
./packages/db/dist/esm/query/ir.js	318 B
./packages/db/dist/esm/query/live-query-collection.js	2.46 kB
./packages/db/dist/esm/query/optimizer.js	2.44 kB
./packages/db/dist/esm/SortedMap.js	1.24 kB
./packages/db/dist/esm/transactions.js	2.29 kB
./packages/db/dist/esm/utils.js	419 B
./packages/db/dist/esm/utils/btree.js	5.93 kB
./packages/db/dist/esm/utils/comparison.js	718 B
./packages/db/dist/esm/utils/index-optimization.js	1.62 kB

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

[github-actions]

Size Change: 0 B

Total Size: 1.05 kB

ℹ️ View Unchanged

Filename	Size
./packages/react-db/dist/esm/index.js	152 B
./packages/react-db/dist/esm/useLiveQuery.js	902 B

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