josh/ytplayer
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Plan phase 6: diagnose and fix WebKit cold delivery

Browse Source
This commit is contained in:
Jonathan Sykes
2026-10-08 08:27:08 +08:00
parent 21c12733d3
commit af6aabc3b7
1 changed files with 11 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
plans/phase6-plan.md Normal file
View File

@@ -0,0 +1,11 @@
# Phase 6 plan
Start from Phase 5 21c1273. Fix cold first-visit delivery only; preserve playback, banner, migration, exact hashes, contracts/pinning, offline and both rollback flags.
1. Extend perf/baseline.mjs/proxy.mjs with page Resource Timing and complete request waterfalls, and a source-worktree option. Create detached historical worktrees beneath perf/.tmp for Phase 2, 3 and 5 tips. Run isolated WebKit/LTE cold measurements, >=3 runs each. Bisect Phase 3 commits with the same instrumented harness. Test head-loader/CSS discovery, fonts, worker start relative to FCP and immutable HTTP-cache behavior with controlled scratch variants. Record actual evidence in plans/phase6-investigation.md.
2. Add failing tests before each root fix. Likely files: frontend/index.html, lazy.js or a tiny layout bootstrap; frontend/sw.js and asset-sync-core.js only as evidence warrants. Keep the legacy install path and update all-or-nothing behavior intact; cache completed immutable responses safely without any unverifiable body. Preserve selected layout before paint and existing CSS cascade order.
3. Commit each fix separately with frontend and isolated Bun server suites green. Revert individual fixes for rollback; ASSET_HASHING=0/ASSET_SYNC=0 stay supported. Do not deploy or contact production.
4. Run final five-run WebKit cold LTE and lossy medians: FCP <= measured Phase 2 (targets ~1,300/3,800 ms); app.js positive-body responses exactly one; cold wire clearly below baseline. Measure Chromium and warm/offline/core-JS/CSS/feature updates against Phase 5, with repeated medians where regression risk exists. Rerun migration both engines with and without stalls, hidden timers, lazy/seam offline checks, rollback paths and all tests.
5. Self-review master sections 3.2/3.3/6/6b and full diff. Commit <=350-word plans/phase6-report.md with actual before/after table and explicit unmet targets; overwrite DONE06 signal and end.
Risks: CSS cascade/no-flash preservation, duplicate requests crossing browser/worker HTTP-cache partitions, race between page handoff and install, timeout fallbacks delaying cache readiness, CPU contention invalidating timing. Historical worktrees/scratch data stay inside wt-assets; run benchmarks sequentially and preserve the invalid historical media fixture only for comparable home-launch metrics, not playback claims.