Skip to content

feat(build): wire build-time layout classification into the generated RSC entry [5/6]#842

Draft
NathanDrake2406 wants to merge 5 commits intocloudflare:mainfrom
NathanDrake2406:feat/pr-768-5-build-classification-wire
Draft

feat(build): wire build-time layout classification into the generated RSC entry [5/6]#842
NathanDrake2406 wants to merge 5 commits intocloudflare:mainfrom
NathanDrake2406:feat/pr-768-5-build-classification-wire

Conversation

@NathanDrake2406
Copy link
Copy Markdown
Contributor

Summary

PR 5 of 6 — restack of #768. Stacked on #841.

Introduces a Rollup `generateBundle` hook that patches the `__VINEXT_CLASS` stub in the generated RSC entry with a real dispatch table built from Layer 1 (segment config) and Layer 2 (module graph) analysis. The runtime probe loop in `app-page-execution.ts` consults this table and skips the Layer 3 dynamic-isolation probe for layouts proved static or dynamic at build time.

  • New `build/route-classification-manifest.ts` bridges the classifier with the entry template codegen.
  • New `build/layout-classification-types.ts` carries the tagged `LayoutBuildClassification` and `ClassificationReason` types (the latter is used by PR 6; included here so the codegen machinery is self-contained).
  • `classifyLayoutSegmentConfig` in `build/report.ts` returns `LayoutBuildClassification` instead of `"static" | "dynamic" | null`.
  • Runtime `classification` block in the generated entry now passes `buildTimeClassifications` through.
  • Fails loudly if `generateBundle` sees `__VINEXT_CLASS` referenced without the recognized stub body, so the generator and plugin cannot silently drift.

PR 6 turns on the optional debug sidecar (`__VINEXT_CLASS_REASONS`) behind `VINEXT_DEBUG_CLASSIFICATION`.

Stack

  1. [1/6] refactor(app-rsc-entry): centralize request-derived page inputs [1/6] #838 — centralize request-derived page inputs
  2. [2/6] feat(app-router): emit per-layout flags in the RSC payload [2/6] #839 — emit per-layout flags
  3. [3/6] feat(app-router): filter skipped layouts from RSC responses and cached reads [3/6] #840 — filter skipped layouts
  4. [4/6] feat(app-router): send X-Vinext-Router-Skip on navigation requests [4/6] #841 — send X-Vinext-Router-Skip
  5. [5/6] this PR — wire build-time layout classification
  6. [6/6] classification reasons sidecar

Test plan

  • `tests/route-classification-manifest.test.ts` (44 tests)
  • `tests/build-time-classification-integration.test.ts` (5 tests)
  • `tests/build-report.test.ts`
  • `tests/layout-classification.test.ts`
  • `tests/app-router.test.ts` (build-time classification dispatch stub cases)
  • `tests/entry-templates.test.ts` (snapshot regenerated)

@pkg-pr-new
Copy link
Copy Markdown

pkg-pr-new bot commented Apr 14, 2026

Open in StackBlitz

npm i https://pkg.pr.new/vinext@842

commit: 8a427d8

Wire runtime layout classification through renderAppPageLifecycle and
attach the resulting flags as __layoutFlags in the outgoing RSC payload
via buildOutgoingAppPayload. Payload-shape helpers (withLayoutFlags,
isAppElementsRecord, buildOutgoingAppPayload, AppOutgoingElements) live
alongside the existing readAppElementsMetadata so the write and read
boundaries sit next to each other.
…dant clone

- isAppElementsRecord narrowed to Record<string, ReactNode>, but the
  outgoing payload legitimately carries heterogeneous values (ReactNode
  for the rendered tree plus LayoutFlags under __layoutFlags). Widen the
  predicate to Readonly<Record<string, unknown>> so the return type
  matches what the runtime check actually proves.

- buildOutgoingAppPayload spread input.element into a new object before
  passing it to withLayoutFlags, which immediately spreads again. Drop
  the outer copy; withLayoutFlags already guarantees immutability.
…d reads

Introduce app-page-skip-filter.ts with the canonical-bytes guarantee:
the render path always produces the full RSC payload and writes it to
the cache; the egress branch applies a byte-level filter that omits
layouts the client asked to skip, but only if the server independently
classified them as static (computeSkipDecision).

Wire the filter into renderAppPageLifecycle and buildAppPageCachedResponse
so both fresh renders and cache hits honor the skip header. Parse the
incoming X-Vinext-Router-Skip header at the handler scope and thread
the resulting set through render and ISR.

Gate the filter behind supportsFilteredRscStream: false in the generated
entry so this PR is dormant at runtime until the canonical-stream story
is validated. Tests exercise the filter directly by injecting the skip
set into renderAppPageLifecycle options.
Introduce buildSkipHeaderValue and createRscNavigationRequestHeaders
in app-elements. The client-side browser entry now uses the centralized
request-header builder for navigation fetches and forwards the current
layout flags so subsequent navigations can signal which static layouts
the server may omit from the response body.
… RSC entry

Introduce a Rollup generateBundle hook that patches the __VINEXT_CLASS
stub in the generated RSC entry with a real dispatch table built from
Layer 1 segment-config analysis and Layer 2 module-graph classification.
The runtime probe loop in app-page-execution.ts consults this table and
skips the dynamic-isolation probe for layouts we proved static or
dynamic at build time.

Add route-classification-manifest.ts as the codegen glue between the
classifier and the entry template, and flow buildTimeClassifications
through renderAppPageLifecycle so the runtime probe can honor the
build-time decision. Fail loudly if generateBundle sees __VINEXT_CLASS
referenced without the recognized stub body, so generator and plugin
cannot silently drift.
@NathanDrake2406 NathanDrake2406 force-pushed the feat/pr-768-5-build-classification-wire branch from dc802fc to 8a427d8 Compare April 15, 2026 03:47
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet

Projects

None yet

Development

Successfully merging this pull request may close these issues.

1 participant