Fix stream subscription changes made during connect()

[joshuabrink]

What happens

A subscribe() or unsubscribe() called, while connect() is bringing up the sync implementation, is never sent to the PowerSync Service. It returns normally and the client reports the new stream set, but the service keeps the set from when connect() started. The sets stay out of step until the set changes again or the connection restarts.

Why

packages/shared-internals/src/client/ConnectionManager.ts

// connectInternal(), :228
const { sync, onDispose } = await this.options.createSyncImplementation(connector, {
  subscriptions: this.activeStreams,        // (1) the set is read here
  serializedSchema: schema
});
this.syncStreamImplementation = sync;       // (3) only now can (2) reach the implementation

// :358
private subscriptionsMayHaveChanged() {
  this.syncStreamImplementation?.updateSubscriptions(this.activeStreams);   // (2) silent no-op
}

A change landing between (1) and (3) is lost: Too late for the set read at (1), and at (2) syncStreamImplementation is still null, so ?. skips the call without raising anything.

Fix

Save the identity of the set it read at (1), and then after (3) check for a difference, if true then update the stream set.

AI Disclosure

Claude Opus was used to build the reproduction and tests. Issue and fix manually verified.

[changeset-bot]

🦋 Changeset detected

Latest commit: 897cc30

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

This PR includes changesets to release 7 packages

Name	Type
@powersync/shared-internals	Patch
@powersync/adapter-sql-js	Patch
@powersync/capacitor	Patch
@powersync/node	Patch
@powersync/react-native	Patch
@powersync/web	Patch
@powersync/diagnostics-app	Patch

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