fix: Fix createDiffTrigger deadlock when called with a setupContext on single-connection platforms

[Chriztiaan]

Fix for diff trigger lock context option introduced in #888.

Issue

In an app using @powersync/tanstack-db with the on-demandmode on web, live queries/collections never became ready and the database never reached a connected state. The app simply appeared stuck with no errors.

Notably:

• I could only reproduce this on web. The Node-based tests for the tanstack-db PowerSync package ran fine.
• Switching the web database to the OPFSWriteAheadVFS VFS made the application work, which pointed at connection/locking behaviour rather than the trigger logic itself.

Cause

The on-demand mode in tanstack-db calls createDiffTrigger from inside a write lock, passing that lock's
context in as setupContext. However, before createDiffTrigger ever used the provided context, it called getUUID(), which ran this.db.get(...), acquiring a new read lock on the database.

On platforms where read and write access share a single connection queue (the default web setup), that nested read request queues behind the write lock the caller is still holding. This caused a deadlock.

This explains why we didn't see the issue for OPFSWriteAheadVFS as it supports separate write and read connections.

Testing

Tested by hand, and introduced a unit test that reproduced the issue - which also verified the problem was resolved after the code change.

Drive-by change

Changed the API extractor config to use lf newlines instead of the default crlf.

AI Disclosure

I used Claude Fable to help investigate this problem.

[changeset-bot]

🦋 Changeset detected

Latest commit: 6f2cff4

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

This PR includes changesets to release 7 packages

Name	Type
@powersync/common	Minor
@powersync/node	Patch
@powersync/op-sqlite	Patch
@powersync/react-native	Patch
@powersync/tanstack-react-query	Patch
@powersync/web	Patch
@powersync/diagnostics-app	Patch

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