iter-139: perf honesty II — unmeasurable vitals, byte attribution, page identity - #178
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Firefox structurally cannot measure layout-shift/longtask; perf vitals/audit fabricated "good" 0.0 for CLS/TBT anyway. Adds apply_unavailable_metric_fields (mirroring the iter-125 LCP guard) driven by PerformanceObserver.supportedEntryTypes, applied to perf vitals, perf audit, and perf compare. resource_by_type/resource_by_domain/third_party_summary previously excluded the top-level navigation document (a `navigation` entry, never a `resource` entry), making resource_by_type.document contradict navigation.transfer_size and reading third_party_summary as ~100% on pages with no other same-hostname subresources. Folds the navigation entry in as a first-party synthetic resource and adds per-type/per-domain opaque markers. perf vitals/audit also gain page_url + measured_at_ms; perf summary/audit text renderers now middle_ellipsis the slowest-resource URLs. Verified live against real headless Firefox (bbc.com/news, wikipedia.org) before and after the fix. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
…er-139 reuse pattern iter-137 (daemon-mode-parity) merged before iter-138/iter-139 both landed on top of it using the default daemon path, so Theme D's frame-scanning dependency is no longer a blocker. Also note iter-139's shared-helper / shared-spec pattern (middle_ellipsis, UnavailableMetricSpec) as the model to follow if Theme D/A/B end up needing the same field-shape logic in more than one place. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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Summary
perf vitals/perf audit/perf comparereported a fabricated "good"0.0for CLS/TBT — Firefox'sPerformanceObserver.supportedEntryTypeshas neitherlayout-shiftnorlongtask, structurally, so these can never be measured. Addsapply_unavailable_metric_fields(mirroring the iter-125 LCP guard, driven by the browser's ownsupportedEntryTypeslist) so both now reportnull/"unavailable"plus a note naming the missing entry type. Verified live on bbc.com/news and en.wikipedia.org, before and after the fix.resource_by_type/resource_by_domain/third_party_summarypreviously excluded the top-level navigation document (anavigationentry, never aresourceentry per the Resource Timing spec), soresource_by_type.document(a few hundred bytes, populated only by incidental ad iframes) contradictednavigation.transfer_size(tens of KB), and pages with no other same-hostname subresources read as ~100% third-party. Folds the navigation entry in as a first-party synthetic resource for these breakdowns, and adds per-type/per-domaintransfer_size_opaquemarkers (previously only flagged at the top-level summary).perf vitals/perf auditgainpage_url+measured_at_ms, so stale (pre-navigation) numbers are detectable instead of silently looking current.perf summary/perf audit --format text"slowest resources" tables now apply iter-128'smiddle_ellipsisto URLs — ad-tracker query strings previously produced single lines of 6000+ chars.Test plan
cargo fmt,cargo clippy --workspace --all-targets -- -D warnings,cargo test --workspace -qall greencargo run -p xtask -- check-iteration-ready --plan kb/iterations/iteration-139-perf-honesty-2.md --base origin/main— 10/10 PASStests/live/live_139_perf_honesty_2.rs, all run and passed against real headless Firefox over the default daemon path (no--no-daemon):live_139_cls_unavailable,live_139_tbt_unavailable,live_139_audit_document_bytes_agree,live_139_audit_opaque_flagged_per_type,live_139_third_party_excludes_first_party,live_139_vitals_page_identity,live_139_perf_summary_text_boundedentry_type_supported, and text-truncation🤖 Generated with Claude Code## Claims vs code
<generated 2026-08-10T14:23:34Z by ralph-loop>
apply_unavailable_metric_fields→ ✅ matched in diff