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fix(utils): handle Web Locks API tab backgrounding in SSE multiplexer#9252
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fix(utils): handle Web Locks API tab backgrounding in SSE multiplexer#9252tmdeveloper007 wants to merge 1 commit into
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@SandeepVashishtha Ready for review — PR #9252: fix SSE multiplexer Web Locks promise hanging when tab is backgrounded by adding visibilitychange listener and proper lock release. |
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Summary
The
SSEClientinsrc/utils/sseMultiplexer.jsused the Web Locks API for leader election. When a browser tab was backgrounded or suspended, the browser automatically released the Web Lock — but the internalreleaseLockPromisewas never called, causing the promise to hang indefinitely and leaving the tab in an inconsistentisLeader = falsestate.Changes
visibilitychangelistener inside the Web Locks request callback to detect when the tab moves to backgrounddocument.visibilityState === "hidden", the fix callsstopHeartbeatChecks(), setsisLeader = false, resolvesreleaseLockPromise, and transitions to localStorage-based election so another tab can claim leadershipreleaseLockPromiseto also remove thevisibilitychangelistener on resolve, preventing memory leaksImpact
Multi-tab SSE scenarios are now stable: backgrounded tabs properly release leadership, preventing heartbeat failures, duplicate SSE connections, and inconsistent subscriber state.
Closes #9247.