Repair webscene-uic compiled selector serialization #663

Active implementation checkpoint — 19 September 2026

Exact upstream heads are WebScene 91fa294f5616f94ba5a24b3b08cdf7307166fc6e and AppScene fe14e7b775d347693d6526b7c4d49c0dca082e52; unchanged Code OSS is 645f29cc3176500b4b5762ba887cf2a7f0ffdf2c. Local vscode-demo is c543d2ca9ff97f3c9e256c5eda4193fad5b53c13 and remains intentionally unpushed with Actions disabled.

Merged Linux exact-device work remains complete through WebScene #654 and AppScene #270. Linux CLIPBOARD/PRIMARY and inbound/outbound Xdnd are merged through WebScene #658 and AppScene #280. CSS animation direction #659/#660 and fill modes #661/#662 are merged. The current-main native compiler failure exposed by #662 is tracked and fixed by #663/#664; generated selectors now preserve compiled namespace-aware compound and attribute data. #666/#667 binds the remaining native test consumer to the namespace-aware compiler API, and #668/#669 restores complete structured selector parity comparisons. #665/#670 implements demand-free animation pause/resume, and #671/#673 enforces parser package size with both ratio and absolute byte budgets, and #672/#678 implements bounded eight-track animation-list coordination; #674/#681 implements zero-time/count semantics, #679/#680/#682 updates the native stale-track contract for inactive authored list slots, and #675/#683 adds bounded translate/scale keyframe sampling and retained paint composition. #684/#685 refreshes the generated Code OSS ledger and exact property identity count exposed by the post-merge main jobs. #676/#686 adds bounded retained ::before/::after animation lifecycle, scoped paint, owner events, cleanup, and demand-free settled state. Full-V8 package portability epic #687 is implemented by #688/#691 for GCC, #689/#692 for MSVC enum/ABI boundaries, #690/#693 for bounded embedded source literals, #694/#695 for const cascade roots, and #696/#697 for native test syntax. #677/#698 adds bounded retained WAAPI with document/element caps, lifecycle settlement, and demand-free inactive states. #699/#700 restores the 384-byte native document footprint by moving WAAPI-only maps and event state behind one lazy auxiliary allocation. #476/#702 adds bounded asynchronous document fetch and stale-generation suppression for dynamically inserted CSS imports, complementing #480/#484 authored-import reflection. #701/#703 adds browser-shaped Worker options, inherited credential policy, final response/CORS enforcement, generation-safe failure, and bounded slot retirement. #704/#705 adds an optional bounded redirect ledger and per-hop Worker status/scheme/loop/downgrade/origin/CORS/credential checks. #706/#707 extracts bounded request-header ABI v5 onto current main; AppScene #281/#282 and vscode-demo #10 populate the ledger in their host providers.

One-agent mode is enforced. The sole implementation agent is implementing bounded interactive reportValidity feedback under #708; no other implementation agent is active. Static fill does not sustain frame demand, and new animation work must preserve that bound without per-frame cascade, selector, or visual-tree churn.

Consolidations remain open and unmerged: WebScene #76 at b1f4977691938e636c1e16ac1c2f37c4d2128f4c, AppScene #65 at 0c018306458050a66a19d2c84abd3cf65a20832c, and vscode-demo #1. WebScene #662 and #681 portable V8 contracts passed. Focused #682 native document and Linux SDK runs 35448768204 and 35448768281 passed; #683 portable V8 contracts passed. The failed #683 current-main generated-ledger/property-count gates are repaired by #684/#685, and Linux CI job 105914816775 passed. Full-V8 Linux/Windows RID portability repairs are merged through #691-#697; current-main CI/NuGet runs 35454910272 and 35454910266 are retained; superseded PR, previous-main, and consolidation runs were cancellation-requested. AppScene #282 current-main companion run 35454940645 passed.

Ordered next work: #708 interactive validity feedback, then current-main CI/package triage and the remaining focused CSS and acceptance backlog, then physical Linux pixels, synchronization/device-loss/resize/soak/performance, VM/computer-use, and unchanged Code OSS Release qualification. Rich clipboard MIME, MULTIPLE/SAVE_TARGETS, and the recorded desktop-service/cross-platform backlog remain open.

Problem

The current WebScene main cannot complete the native Linux document/compiler contract. webscene-uic still emits compiled attribute selector entries as strings, while the shared selector model now stores compiled_css_attribute. Clang fails at tooling/webscene-uic/main.cpp:1867 because quote(attr) accepts a string view.

This is a latent integration regression from the compiled namespace-selector model and blocks current-main CI after #662.

Scope

• Serialize every field of compiled_css_attribute: local name, optional namespace URI, operator kind, value, and case-sensitivity.
• Preserve compound namespace metadata in generated prepared selectors.
• Preserve pseudo name/argument and validity metadata without attempting to serialize shared pointer graphs.
• Keep generated C++ deterministic and safely escaped.
• Add a focused generator/source contract for namespace-qualified attribute selectors so model changes cannot silently leave webscene-uic behind.
• Keep the generator path allocation-bounded and outside runtime selector matching, cascade, layout, and frame scheduling.

Acceptance

• webscene-uic compiles against the current shared CSS state types.
• Generated prepared selectors preserve namespace and attribute matching semantics.
• The native document/compiler workflow no longer fails at the stale string serializer.
• No VS Code-specific patch and no browser/Electron dependency.

Relationship

CSS tooling correctness child of #235. This repair is independent of the animation-fill behavior merged in #662, which merely triggered the current-main contract that exposed it.