[Fix] SSR Mode Detection

[stevensJourney]

Overview

This fixes an issue where manually specifying ssrMode: true in the PowerSyncDatabase constructor flags could cause unexpected syncing behaviour to occur in the browser client.

Previously the WASQLiteOpenFactory did not account for the ssrMode flag. This would create a DBAdapter based on the detected environment. Specifying ssrMode: true would result in a functional WASQLiteDBAdapter being created (on the client).

Previously the SSRStreamingSyncImplementation extended AbstractStreamingSyncImplementation which contains logic for processing sync commands from the server. Sync commands would be a no-op if the suppled DBAdapter was a placeholder SSR DBAdapter, but as described above this was not the case if ssrMode: true was specified.

The locks in SSRStreamingSyncImplementation are not exclusive, which could result in multiple clients processing sync commands into a single SQLite DB. This PR removes the ability for SSRStreamingSyncImplementation to perform any actual syncing. This implementation is just meant to be a placeholder for cases where the PowerSyncDatabase client is accidentally used or exposed on the server.

[changeset-bot]

🦋 Changeset detected

Latest commit: a1b5110

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

This PR includes changesets to release 4 packages

Name	Type
@powersync/common	Minor
@powersync/web	Minor
@powersync/react-native	Patch
@powersync/diagnostics-app	Patch

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[guillempuche]

I don't find this mode in the docs. What is it about?

[stevensJourney]

I don't find this mode in the docs. What is it about?

We have a TODO for adding SSR docs.

In short: Our web SDK requires web APIs. WebAPIs are not available when the server might be rending components for SSR. Using web APIs on the server typically throws exceptions for missing methods. Our web SDK is not meant to be used on the server-side, but we provide these helpers which will avoid actually performing and DB or sync operations if a developer accidentally ends up attempting to use the SDK on the server-side.