feat(app): warn when one-shot handlers are registered after connect()#629
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feat(app): warn when one-shot handlers are registered after connect()#629
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Mirrors the outbound-side guard from #623: registering a toolinput / toolinputpartial / toolresult / toolcancelled handler after the ui/initialize handshake has completed now logs a console.warn (or throws under { strict: true }), since the host may have already fired the notification by then. hostcontextchanged is exempt — late listeners for repeating events are legitimate. Covers both the on* setters and addEventListener.
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…631) * fix(react): close App on useApp unmount; relax late-handler guard for re-registration useApp's effect cleanup now closes the App (and its transport) instead of only flipping a `mounted` flag. Under React StrictMode dev double-invoke, the abandoned first instance's PostMessageTransport otherwise keeps a window `message` listener and receives every host postMessage alongside the second instance. The late-handler guard from #629 now tracks `_everHadListener` per event and only flags the *first* registration of a one-shot event post-handshake. Re-registration (React useEffect cleanup + re-add on dep change) of an event that had a pre-connect handler is silent, including under `strict: true`. * feat(app-bridge): warn on second ui/initialize If a View double-mounts (e.g. React StrictMode in dev) without closing the previous App, AppBridge now logs a console.warn when it receives a second ui/initialize. Behavior is unchanged — it still responds and the latest appInfo/appCapabilities replace the previous values — this is purely a diagnostic for host implementers.
This was referenced Apr 21, 2026
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Summary
Companion to #623's outbound guard. Registering a
toolinput/toolinputpartial/toolresult/toolcancelledhandler afterapp.connect()has completed theui/initialize→ui/notifications/initializedhandshake now:console.warnby default, ornew App(appInfo, caps, { strict: true }).The host may have already sent these one-shot notifications by the time a late handler is attached, so the callback silently never fires (#476).
hostcontextchangedis exempt since late theme/locale listeners are normal.Applies to both the
on*setters andaddEventListener. Clearing a handler (app.ontoolinput = undefined) does not warn.Test plan
npx tsc --noEmit— 0 errorsnpm test— 327 tests, 0 fail (6 new inpre-handshake guard › late handler registration)connect(); warning after; throw understrict;hostcontextchangedand handler-clear exempt