[Epic] Complete remaining Code OSS native release acceptance

[wieslawsoltes]

Exact merged-head diagnostic checkpoint — 21 September 2026

Unchanged Code OSS 645f29cc is pinned locally with merged WebScene 5b4739c8 (native stack #902, focused PRs #899–#901 merged) and merged AppScene 36d7a82e (focused PR #403 merged). The demo branch is clean at local commit 074d2cbe, unpushed, with Actions disabled. No focused PRs remain open; keep WebScene consolidation #76, AppScene consolidation #65 and vscode-demo integration #1 open/unmerged.

A clean 2,909-file SDK from those exact heads passed native CTest, macOS runtime profile, installed CLI verification and release preflight. The CLI published a signed 709 MiB local diagnostic Release at vscode-demo/dist/appscene-release-36d7a82-5b4739c8-markdown/Code OSS AppScene.app; strict codesign and the installed-resource callback contract pass. Native computer input opened real remote beta/README.md and five Explorer rows. A Markdown Preview editor then appeared with a blank white pane; the current trace does not isolate the next nested resource/message failure, and the shortcut sequence also pasted clipboard text into the fixture editor. This is not a qualified full release. AppScene #402/#398 and WebScene #264/#267 stay open.

Resume with controlled native Preview invocation and nested resource/worker/message tracing; require actual painted Markdown, Chromium-matched geometry, security, lifecycle and performance. Then continue Explorer first-child paint #252/#243 and AppScene picker #131, remote Save As/recovery #269, terminal #244, CSS #235, accessibility/Chat, Linux/Windows WPT, bundle-size and release-wide CI gates. The authored open-issue inventory and exact local evidence are in vscode-demo/docs/open-issue-plan.md and docs/validation/markdown-preview-prelude-080ee9c-20260921.md. No Electron/CEF shell or Code OSS source rewrite was introduced.

Goal

Run unchanged VS Code OSS 1.137 as a native AppScene/WebScene application with its Node server and extension host, without Electron, Chromium, CEF, WKWebView/WebView, a browser process, or a C++ port. Reusable behavior belongs in AppScene or WebScene; vscode-demo owns only product configuration, evidence, and the unmerged integration branch.

This is the top-level native GitHub epic for all remaining integration-owned work.

Planning status — investigation gate complete

Four parallel audits completed before implementation resumed:

1. all current AppScene/WebScene issues, PRs, coordination comments, release gates, desktop-capability decisions, and product surfaces;
2. CSS/features/visual-tree/performance under [Epic] CSS features, compatibility, validation, and performance #235;
3. webviews/iframes/Markdown and every unchanged nested-document consumer under [Epic] Qualify unchanged Code OSS webviews and nested document contexts #264;
4. files/folders/workspaces/save/recovery under SceneTech/AppScene#122.

Every reproduced gap and required release surface now has one authoritative issue, repository owner, dependency position, proposed fix direction, browser/WPT/native/product evidence, numeric performance/lifecycle limits, and proposed PR-stack grouping. Duplicate ownership was explicitly rejected. The only cross-cutting overlap with special handling is #263/#236: #236 is the authoritative CSS capability source and #263 must ingest it with revision and denominator checks.

Current inventory:

• 37 open integration-authored WebScene issues, all carrying vscode-oss/planned and placed in this hierarchy;
• 4 open integration-authored AppScene issues, all carrying vscode-oss/planned and placed in this cross-repository hierarchy;
• [Epic] Complete remaining Code OSS native release acceptance #227 has 15 direct native children;
• CSS epic [Epic] CSS features, compatibility, validation, and performance #235 has 33 native children (16 open, 17 closed history);
• webview epic [Epic] Qualify unchanged Code OSS webviews and nested document contexts #264 has 5 native children;
• file/workspace epic SceneTech/AppScene#122 has 3 native children.

Historical exact inputs and coordination state

This preserved checkpoint predates the authoritative managed section above.

• Historical AppScene main: 1420e227e52579a097e7ae52a2cadb41cf073e4d.
• Historical WebScene main: aa786c0ea2bbd21599f33caf3795c0eacc19ace3.
• VS Code OSS: unchanged 645f29cc3176500b4b5762ba887cf2a7f0ffdf2c (1.137.0).
• AppScene Stream native application video directly from file and network URLs #65: draft consolidation refreshed through current main at dbb3517; guide-only unique diff; lifecycle check green.
• WebScene Add Code OSS browser and native desktop compatibility #76: draft consolidation refreshed through current main at ebb74384; guide-only unique diff; Linux/macOS/NativeAOT 11/12 checks green.
• vscode-demo Typescript #1: draft/open/unmerged; repository Actions disabled; local commits intentionally unpushed.
• External WebScene PR Optimize structural CSS invalidation and DOM mutation checkpoints #245 owns structural CSS invalidation and overlaps Keep active MessagePort listeners reachable across garbage collection #288 MessagePort reachability. Its exact theme probe passed only at 05aa8f12; current head 47e84144 owns 83 paths and remains draft/unstable. Do not duplicate it. Reconcile/rebase, then rerun its direct Complete selector matching, specificity, and dependency invalidation coverage #237, Keep active MessagePort listeners reachable across garbage collection #288, and installed-SDK gates.
• AppScene Implement Node.hasChildNodes for DOM consumers #84 is unrelated Spotify work and does not overlap these lanes.

The exact AppScene/WebScene SDK archive from the current submodule inputs contains 2,859 verified files and passes producer, CLI install/verify/doctor, relocation, read-only, external-consumer, lifecycle, and integrity checks. It is not release-qualified because #237 currently fails on WebScene main. No .app is promoted from these heads.

Native hierarchy and ownership

Direct children of #227

• Add V8 Inspector/CDP support for Chrome DevTools debugging #7 — opt-in Inspector/CDP developer tooling; post-release unless it becomes a blocker.
• Implement Worker, transferable MessagePort, and iframe contexts for Code OSS #81 — Worker, transferable MessagePort, structured clone, Monaco/browser extension-host acceptance; native child Bound the packaged remote extension-host Ready-to-Initialized handshake #289 owns remote Ready→Initialized latency and Keep active MessagePort listeners reachable across garbage collection #288 owns active-port lifetime.
• Provide crypto.subtle through a vetted cross-platform provider #102 — real MCP/secret Web Crypto consumer acceptance.
• [Epic] CSS features, compatibility, validation, and performance #235 — all CSS features, layout, paint, visual-tree, terminal-performance, and CSS capability work.
• Qualify VS Code remote file and folder picker interaction #247 — exact remote picker selected-URI/openWindow handoff.
• Implement File System Access pickers and handles over AppScene native panels #248 — File System Access APIs over typed AppScene native panels.
• Qualify remote workspace bootstrap, Explorer contents, and watcher refresh #252 — new-document workspace/provider reconstruction, Explorer/watchers, and dependent services.
• SceneTech/AppScene#122 — files/folders/workspaces/save native cross-repository epic.
• Establish Chromium/AppScene visual and geometry regression gates for unchanged Code OSS #259 — common Chromium/AppScene semantic, geometry, readiness, and compact visual-diff harness.
• Qualify all unchanged Code OSS workbench commands, panels, and feature lifecycles #260 — complete workbench command/panel/feature-lifecycle scenarios.
• Qualify Code OSS Chat and auxiliary-bar interaction, streaming, and lifecycle #261 — deterministic Chat/auxiliary-bar interaction, streaming, Markdown, and lifecycle.
• Qualify Code OSS accessibility semantics, keyboard navigation, and native exposure #262 — semantic DOM/ARIA, keyboard/focus, and native accessibility exposure.
• Publish a Code OSS Web API capability ledger and expand WPT coverage #263 — reachable Web API capability ledger and non-CSS WPT expansion.
• SceneTech/AppScene#130 — exact installed-SDK/CLI Release build, package/disk budgets, signing, lifecycle, and zero-browser promotion.
• [Epic] Qualify unchanged Code OSS webviews and nested document contexts #264 — all unchanged webviews and secure nested-document contexts.

CSS epic #235

Open owners remain #237–#244, #44, #100, #112, and #246; #236 completed through PR #271. The completed audit added:

• Implement CSS containment, container queries, and content visibility for dynamic panels #254 — containment, container queries, and content visibility;
• Qualify forced-colors, system colors, focus visuals, and motion preferences #255 — forced/system colors, focus visuals, and motion preferences;
• Render CSS masks, filters, clip paths, and backdrop effects in retained scenes #256 — masks, filters, clip paths, and backdrop effects;
• Match live form-control pseudo-class state and bounded invalidation #257 — live form-control pseudo state and bounded invalidation;
• Bound visual-tree churn, idle publication, and memory across panel mutations #258 — panel visual-tree churn, idle publication, retained nodes, latency, and RSS slope.
• Decode CSS string and url() escapes before resource resolution #286 — CSS string and url() escape decoding before resource resolution.

#236 dependency order zero completed through PR #271 at aa121fe. #237 coordinates with PR #245; Wave 1 #257 waits for that draft to reconcile. #238/#239/#240/#242 remain the sole owners of general cascade, CSSOM, layout, and animation work.

Webview epic #264

Ordered native children:

1. Expose HTMLIFrameElement.sandbox for Code OSS webviews and Markdown Preview #253 — HTMLIFrameElement.sandbox IDL, live token list, enforcement, navigation, teardown.
2. Complete ServiceWorker control and client lifecycle for Code OSS webviews #265 — ServiceWorker registration/control, Clients, controller lifecycle.
3. Stream and cache admitted Code OSS webview resources #266 — Web Streams, CacheStorage, FetchEvent, admitted/ranged/cached resource broker.
4. Enforce secure nested-document lifecycle for Code OSS webviews #267 — nested src/srcdoc/fake.html realms, open/write/close, origins, CSP, Permissions Policy, replacement, teardown.
5. Complete nested-webview interaction, find, focus, and accessibility handoff #268 — find/Selection, focus/input, clipboard, links/downloads, reload, and accessibility handoff.

The exact first failure remains unchanged Code OSS calling iframe.sandbox.add(...) while WebScene exposes undefined. The deeper audit proves sandbox alone is insufficient: the unchanged prelude then requires ServiceWorker control, resource streaming/cache, secure nested-document lifecycle, and interaction behavior. Markdown Preview is the first fixture, not the scope boundary.

File/workspace epic SceneTech/AppScene#122

Native children are AppScene#123 (typed native panels/grants), AppScene#124 (owned-window navigation), and WebScene#269 (file model/save/revert/hot-exit recovery). Related WebScene owners remain #247, #248, and #252.

WebScene #247 is complete. The real remote dialog enumerated and accepted the isolated fixture; a ready-workbench sample reached visibility in 901.25 ms with 122 maximum dialog nodes. Exact Node 24.18.1 evidence retained BrowserHostService.openWindow call 1 with vscode-remote://127.0.0.1:64170/private/tmp/webscene-247-fixture/beta, folder kind, and all force-new/reuse/add flags false. No generic engine defect was found. AppScene#124 and #252 now own navigation and new-document workspace/provider/Explorer bootstrap.

Four-agent delivery schedule

No agent shares implementation files with another active lane. Before starting/rebasing and immediately before merging, each lane rescans open issues, PRs, and recent comments.

Wave 0 — current foundations

Agent lane	Work	Exit condition
Webview	#253 Stack A: sandbox IDL/live token semantics → security/navigation/teardown → WPT/browser/native/Markdown proof	Unchanged iframe creation passes with bounded teardown; focused cumulative top ready to merge
Files/workspaces	Complete: #247 exact selected URI/openWindow handoff	Exact target retained; #247 closed with Node 24.18.1 evidence and no engine defect
CSS/capability	Complete: #236 schema/report/validator merged through PR #271 as aa121fe; no #245 structural file changed	Native 32/32 and Chrome 25/32 with all seven failures retained; #263 consumes the versioned CSS slice and #245 can be requalified independently
Root/release harness	#263 reachability ledger foundation plus #259 scenario/readiness/visual-manifest inventory; keep #227 and vscode-demo #1 synchronized	All accepted scenarios and evidence denominators are machine-readable and compact

Wave 1 — unblock complete editor surfaces

• Webview: Complete ServiceWorker control and client lifecycle for Code OSS webviews #265 then Stream and cache admitted Code OSS webview resources #266 as a dependent stack: control plane → streams/cache/resource plane.
• Files/workspaces (active): AppScene#124 same-window target/navigation and Qualify remote workspace bootstrap, Explorer contents, and watcher refresh #252 new-document provider/root/Explorer/watchers at their explicit boundary; split new-window work behind AppScene#41.
• CSS: after Optimize structural CSS invalidation and DOM mutation checkpoints #245 is reconciled, Match live form-control pseudo-class state and bounded invalidation #257 live state; independently start Implement CSS containment, container queries, and content visibility for dynamic panels #254 containment/container queries and Qualify forced-colors, system colors, focus visuals, and motion preferences #255 environment/focus/motion where files do not overlap.
• Root: complete Establish Chromium/AppScene visual and geometry regression gates for unchanged Code OSS #259 common oracle, then build Qualify all unchanged Code OSS workbench commands, panels, and feature lifecycles #260 deterministic editor/Search/SCM/tasks/run/debug/extensions/workbench scenario manifests.

Wave 2 — secure behavior, durability, and measured performance

• Webview: Enforce secure nested-document lifecycle for Code OSS webviews #267 then Complete nested-webview interaction, find, focus, and accessibility handoff #268 cumulative nested-realm/security/interaction/accessibility stack.
• Files/workspaces: Qualify VS Code file edit, save, revert, and hot-exit recovery #269 remote open/edit/save/revert/backup/hot-exit; then AppScene#123 → WebScene#248 typed panel/grant/File System Access stack and local Save As.
• CSS/performance: Render CSS masks, filters, clip paths, and backdrop effects in retained scenes #256 retained effects; Bound visual-tree churn, idle publication, and memory across panel mutations #258/Profile unchanged VS Code CSS and visual-tree workloads with bounded performance gates #243 measured panel mutation, idle CPU, publication, memory, and targeted fixes; Bound and reduce VS Code integrated-terminal open-to-prompt latency #244 terminal phase attribution and only the largest proven engine-owned optimization.
• Root/product: Qualify Code OSS accessibility semantics, keyboard navigation, and native exposure #262 semantic/native accessibility and Qualify Code OSS Chat and auxiliary-bar interaction, streaming, and lifecycle #261 deterministic Chat acceptance, consuming Implement CSS containment, container queries, and content visibility for dynamic panels #254/Render CSS masks, filters, clip paths, and backdrop effects in retained scenes #256/Establish Chromium/AppScene visual and geometry regression gates for unchanged Code OSS #259/Publish a Code OSS Web API capability ledger and expand WPT coverage #263 rather than duplicating them.

Wave 3 — cumulative unchanged-product acceptance

Close only from exact package evidence:

• Add native input observability and Code OSS activation gates #100 Command Palette/input/pointer and Match absolute modal and nested Settings layout used by VS Code OSS #112 Settings/select behavior;
• Render generated icon-font pseudo-elements correctly in tabs and list rows #246 active tab/Explorer visual artifact;
• Implement Worker, transferable MessagePort, and iframe contexts for Code OSS #81 real Monaco and browser extension-worker requests, visible failures, teardown;
• Provide crypto.subtle through a vetted cross-platform provider #102 real configured MCP secret persistence/reopen;
• Qualify VS Code remote file and folder picker interaction #247/Implement File System Access pickers and handles over AppScene native panels #248/Qualify remote workspace bootstrap, Explorer contents, and watcher refresh #252/Qualify VS Code file edit, save, revert, and hot-exit recovery #269 and AppScene#123/Emit browser-compatible punctuation keyboard events #124 complete file/workspace/save flows;
• Expose HTMLIFrameElement.sandbox for Code OSS webviews and Markdown Preview #253/Complete ServiceWorker control and client lifecycle for Code OSS webviews #265–Complete nested-webview interaction, find, focus, and accessibility handoff #268 representative Markdown, notebooks, custom editors, extension panels/views, release notes, Getting Started, image, Chat/MCP, Mermaid, and Simple Browser webviews;
• Implement CSS containment, container queries, and content visibility for dynamic panels #254–Bound visual-tree churn, idle publication, and memory across panel mutations #258 plus Profile unchanged VS Code CSS and visual-tree workloads with bounded performance gates #243/Bound and reduce VS Code integrated-terminal open-to-prompt latency #244 CSS/visual/performance/accessibility gates;
• Establish Chromium/AppScene visual and geometry regression gates for unchanged Code OSS #259–Publish a Code OSS Web API capability ledger and expand WPT coverage #263 full visual, workbench, Chat, accessibility, and Web API/WPT matrices.

Wave 4 — release production

SceneTech/AppScene#130 consumes one exact clean set of merged AppScene/WebScene heads and unchanged VS Code:

1. build/install/relocate/read-only-qualify one SDK through the AppScene CLI;
2. build, run, publish, sign, and verify the .app, ZIP, and DMG;
3. enforce architecture/dependency/license/inventory, deep signature, archive round trip, zero-browser, feature-preserving size, peak disk, retained-artifact, and package-time budgets;
4. run complete editor/workbench, visual, file/workspace/save, webview, terminal, workers/extensions, crypto/MCP, accessibility, CSS/performance/memory, reload/close/crash/SIGKILL/descendant-cleanup gates;
5. promote only a fail-closed green package and retain compact checksummed evidence.

PR stacks and merge policy

• Each issue body defines its proposed stack. Related dependent PRs use GitHub native stacks; validate the cumulative top and merge the stack atomically.
• Merge a focused AppScene/WebScene fix as soon as its directly related local and runner gates pass. Cancel duplicate lower-layer, unrelated broad, superseded, and post-merge jobs.
• Every generic fix needs a browser-oracle/WPT-derived regression, native contract, and bounded performance/allocation/lifecycle gate for the changed hot path.
• AppScene Stream native application video directly from file and network URLs #65, WebScene Add Code OSS browser and native desktop compatibility #76, and vscode-demo Typescript #1 remain draft/open/unmerged. vscode-demo Actions remain disabled. Local vscode-demo commits remain unpushed.
• No implementation, test, CI, SDK, or packaging logic may remain only on a consolidation branch; reusable behavior moves upstream first.

Release quality gates

Evidence must name exact source, SDK, WPT/browser, OS, font, locale, theme, DPR, hardware/runner, and package checksums. Reports expose pass/fail/skipped/unavailable/total denominators; missing or stale evidence fails closed.

Required gates include semantic/computed state, geometry, pixels, focus/accessibility, event order, security/origin/admission, affected cascade/layout/scene counters, wall time, allocations, queue high-water marks, publications/frames, idle CPU, peak/steady RSS, repeated-cycle live-count return, no memory slope, installed/relocated/read-only SDK consumers, supported release RIDs, feature-preserving size, bounded disk/artifacts, deep signing, lifecycle, and static/runtime absence of embedded browser technology.

Ownership

• WebScene: V8, DOM/HTML, Web APIs, CSS/layout/paint, workers/ports, iframe/service-worker contexts, scene publication, and product-neutral performance contracts.
• AppScene: SDK/CLI, native host/window lifecycle, panels/grants, native accessibility/desktop dispatch, packaging, signing, Companion lifecycle, and release production.
• vscode-demo: unchanged-product configuration, deterministic fixtures, Chromium/AppScene comparison, final package evidence, and the open consolidation PR.

Focused issues close only from retained exact evidence. This epic and all three consolidation PRs remain open until the final installed-SDK Release matrix is green.

Active synchronization — 17 September 2026

#276/#278 and #285 are merged. #281 remains draft/open behind #288/#245; #266 is held until that control-plane top merges. Workspace contents pass. #287 fixes its direct FileReader gate locally but is product-insufficient. Exact #81 instrumentation proves the local iframe/Worker/transferred-port path and creates #289 for distinct remote protocol delays (transport→Ready 1,177 ms; Ready→Initialized 4,379 ms); Explorer output follows AgentHost connection by 99 ms. Dependency order is #289 → #280 → #252. #288 remains the separate #281 blocker. CSS #286 is the 33rd #235 child and remains isolated from #245.

Current integration checkpoint — 19 September 2026

WebScene main is 8447e25d24b13dce0af6fc47fa02714ca8119cae and AppScene main is 7c067b3c77d53e5804d3ef756e53ef46516d5c50. Consolidations remain open and unmerged at WebScene #76 8df7d2bb, AppScene #65 459639d3, and vscode-demo #1; local vscode-demo 749e204c remains unpushed with Actions disabled.

The Linux exact-device allocator, synchronized queue access, Skia Graphite profile, single-plane external-image draw, Xlib swapchain present and completion retirement stack is merged through WebScene #654 and AppScene #270. AppScene #271/#272 merged the native X11 CLIPBOARD/PRIMARY text service. WebScene #655/#656 and AppScene #273/#274 complete bounded PRIMARY middle-click reads; WebScene #657/#658 and AppScene #275/#276 complete automatic PRIMARY publication; AppScene #277/#278 and #279/#280 complete inbound/outbound Xdnd; WebScene #659/#660 animation direction is merged; the sole lane is WebScene #661 backwards/both fill-mode support.

Full product, visual, WPT, performance, accessibility, file/workspace/webview/terminal, lifecycle, package-size, signing, VM/computer-use, CI and zero-browser Release gates remain open. The latest implementation wave used source diff checks only under the agreed fast merge policy.

[wieslawsoltes]

2026-09-17 focused-work update

• CSS work is now synchronized under native epic [Epic] CSS features, compatibility, validation, and performance #235 with 25 sub-issues. Fix catalog script and logical sizing compatibility #148 is the baseline; Avoid temporary allocations in CSS class-index lookups #233/Avoid allocations in CSS class index lookups #234 is stacked on it and owns only allocation-free class-index lookup. Browser/native 3/3, direct Linux/macOS, and exact allocation/semantic gates pass on the stack. Merge waits for Fix catalog script and logical sizing compatibility #148's own contract/package compile fix and merge.
• AppScene Add HTTP response headers and browser cookie propagation to resource ABI #75 implementation is PR Dispatch finite CSS animation events #119. CLI test/package and focused project contracts pass; full Linux headless qualification remains active.
• A real VS Code UnicodeHighlighter trigger exposed a deterministic U+202E AppScene text-measurement abort. AppScene Skip GPU work for caret-only host frames #120 owns the focused fix; WebScene Implement Worker, transferable MessagePort, and iframe contexts for Code OSS #81 remains open until the actual editor-worker consumer completes.
• vscode-demo local 0d4733f adds first-class Settings Chromium/native state, geometry, and pixel gating. Patched workbench typecheck, 16 Node tests, and 44 Python tests pass. Fresh packaged execution remains required before Match absolute modal and nested Settings layout used by VS Code OSS #112 closes.
• vscode-demo PR Typescript #1 summary was refreshed with the complete stacks, blockers, and final rebuild order. Consolidation PRs remain open/unmerged.