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Complete host-driven native close veto lifecycle #87
Description
AppScene coordination epic: SceneTech/AppScene#66
Problem
Unchanged browser applications use standard window/document APIs for close, focus, fullscreen, visibility, and external navigation. WebScene already translates HTTP(S) anchors and window.open into bounded host requests, but the Runtime contract has no typed close/focus/fullscreen completion path and visibility changes from the native window are incomplete. Code OSS's browser IHostService calls these APIs directly.
Proposed contract
- Define versioned, typed host requests for external URL, close, focus, and fullscreen enter/exit, with request IDs and explicit completion where JavaScript awaits a result.
- Publish native visibility/focus/fullscreen changes back into the correct document realm and dispatch the standard events.
- Keep reload as WebScene navigation using the current URL and navigation-generation cancellation rules.
- Preserve external HTTP(S) handoff as a system-browser action. Reject unsupported schemes and oversized/malformed values before host dispatch.
- Bound pending requests and cancel awaited requests on navigation/teardown.
- Treat auxiliary browsing contexts as a separate capability under AppScene [GPU 19/20] Qualify WebGPU/WebGL conformance, resilience and support claims #41;
window.opencontinues system-browser handoff until that capability is implemented.
Acceptance criteria
- DOM/API contracts cover
window.close/focus,Element.requestFullscreen,Document.exitFullscreen, fullscreen state/events, focus/blur,document.hidden,visibilityState, and reload. - Native contracts cover success, host denial, malformed requests/completions, queue saturation, stale completion, navigation, and teardown.
- A 10,000-operation request/completion gate and a 10,000 visibility/focus transition gate publish elapsed time and bounded high-water metrics without sleep-based correctness.
- Hosted and packaged Windows, macOS, and Linux jobs plus cross-RID/consumer checks pass.
- AppScene qualifies external link, fullscreen round trip, reload readiness, and veto-aware close in the packaged Code OSS app with no VS Code source change.
This is a standard browser/runtime boundary. Platform window operations remain AppScene's responsibility.
Activity
wieslawsoltes commentedon Sep 15, 2026
First implementation commit:
378dd29don consolidated draft PR #76, with the Cocoa host in SceneTech/AppScene029da1fb/ draft PR SceneTech/AppScene#65.Implemented: bounded HTTP(S) handoff, top-level focus/close requests, scripted beforeunload close veto,
location.reload(), Promise-based Element/Document fullscreen entry/exit with state andfullscreenchange, nativedocument.hasFocus()plus focus/blur propagation, existing visibility state/events, navigation cancellation, explicit completion failures, and an oversized JSON request discard contract.Repository CI is running. This stays open for native-initiated fullscreen synchronization, close-button veto qualification, typed request structs, transition/queue performance metrics, Windows/Linux packaged host qualification, and the combined Code OSS interaction gate.
wieslawsoltes commentedon Sep 15, 2026
Implemented at
da6ee30492294b94541ea5137d741916e53e4a2fin draft PR #76. Hosted macOS/Ubuntu/Windows, NativeAOT, native Linux, all three packaged RIDs, installed consumers, cross-RID evidence, and release-package verification pass. Contracts cover bounded focus/close/reload/fullscreen/external-URL requests, close veto, visibility/focus propagation, queue overflow, navigation cancellation, and stale completions.wieslawsoltes commentedon Sep 16, 2026
Reopening for the unchecked native close-button contract. Stack #186 completed the JavaScript-to-host path, but the reverse OS-to-browser lifecycle path is still absent.
Exact gap:
window.close()dispatches cancelablebeforeunloadin WebScene before it emitsWEBSCENE_HOST_REQUEST_WINDOW_CLOSE_V1; AppScene then closes the Cocoa window. This path is veto-aware.NSWindowenters AppScenewindowWillClose/begin_closedirectly. No WebScene ABI lets AppScene ask the active top-level realm to dispatchbeforeunload/pagehideand return the allow/veto decision before teardown.BrowserLifecycleServiceshutdown notification, storage flush, orwindow.confirmBeforeCloseveto on an OS close.Recommended focused stack order:
beforeunloadin the active realm, run the microtask checkpoint, and dispatch the noncancelable terminal lifecycle event only after an allow decision. Cover stale/no-realm/error behavior and repeated requests. Because the browser workbench rejects async vetoes, the current consumer needs a bounded synchronous decision rather than an unbounded callback.windowShouldClose, returnNOon veto, and distinguish an already-approved JavaScriptwindow.close()host request so it does not dispatchbeforeunloadtwice. Preserve an explicit compatibility policy when the symbol is absent.window.confirmBeforeClose, allowed close with lifecycle/storage evidence, repeated normal close, and teardown. Keep external-link/fullscreen/reload package checks alongside this gate.The existing typed desktop ABI and pending-host teardown from merged Stack #186 remain the prerequisite. SceneTech/AppScene#67 stays open for layer 2 and combined acceptance; AppScene #100 independently fixed composite visibility state.
[-]Add typed native window lifecycle and fullscreen host contracts[/-][+]Complete host-driven native close veto lifecycle[/+]wieslawsoltes commentedon Sep 16, 2026
The generic host-driven close contract is now merged in #202 (
c83432769ab41ff14c26aa901b2e713503e76ab1).Evidence:
webscene_engine_request_window_close_v1returns explicit error/allow/veto decisions and runs on the owning V8 worker while the host waits synchronously through a bounded queue/wait.beforeunload; its microtask checkpoint drains before the result. Veto suppresses terminal lifecycle. Allow dispatches one noncancelablepagehidewithpersisted=false; repeated approved requests coalesce until navigation.portable-v8-contract.9d627ea3aeb2444bf5a467370c7eff2950453ca5): CocoawindowShouldClosehonors veto/error and bypasses exactly one decision for an already approved JavaScriptwindow.close()request.The remaining acceptance is the packaged Code OSS close-veto/storage/lifecycle qualification tracked by SceneTech/AppScene#67. Leaving this issue open until that cross-repository acceptance is recorded.
wieslawsoltes commentedon Sep 17, 2026
Closed by the merged typed host/window lifecycle contracts and exact packaged acceptance.
Source coverage is complete through PRs #202/#206 and the terminal lifecycle fixes #215 (
547395f2) and #217 (13c93852). Focused portable runners passed. Inspector Release gates completed 10,000 native decisions in 0.057832 seconds and 10,000 script closes in 0.00124571 seconds with stable V8 heap.Against final WebScene
24db1a2f/ AppScened7cbbaf9, three packaged Code OSS cycles each passed external-link handoff, fullscreen enter/exit, top-level reload, native close veto, and JavaScript-approved close. Every cycle observedbeforeunloadcounts 0→1→2 and exactly one terminalpagehide; recursive/capacity behavior remained bounded and repeated teardown left no processes. This satisfies the browser API, host denial/veto, ordering, capacity, reload, and packaged desktop round-trip scope. Consolidation PR #76 stays draft/open/unmerged.