feat(diff): compare computed values canonically — a re-serialization isn't a change#161
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…isn't a change Dogfooding a real re-baseline showed StyleProof reporting a flood of "changes" that weren't: a newer Chromium serialized identical values differently — rgba(8, 18, 32, 0.62) became #0812209e, a font list's comma spacing shifted — and every one read as a diff, drowning the review and blowing the report up to hundreds of MB. A green flickered red purely across browser versions. Compare by a canonical form instead: colours parse to one rgba() (hex / rgb / rgba / hsl / hsla, short+long hex, comma + modern space syntax), and comma/whitespace runs normalize outside quotes. Captures become serialization-independent. Safety bar — only PROVABLY-equal values collapse: an unparseable value (or anything inside a quoted string) is left byte-for-byte, so a real change (#ff0000 → #ff0001, 0.5 → 0.6 alpha, a different font) always still surfaces. The report shows the real captured strings; only the equality test is canonical. Custom props stay ignored; content/text diffs stay exact. Tests: test/canonicalize.test.mjs — equal spellings collapse, real changes never do, quoted/unparseable left untouched, and diffStyleMaps yields zero findings for a serialization-only difference. Full suite 255/255 (no existing diff test regressed). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
🗺️ StyleProof report📊 View the side-by-side visual report →To accept: rebuild the map with |
Fallow audit reportNo GitHub PR/MR findings. Generated by fallow. |
Fallow audit report0 inline findings selected for GitHub review. |
# Conflicts: # CHANGELOG.md # package.json
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What and why
StyleProof stops reporting a change when the browser merely re-serialized an identical
value. Dogfooding a real re-baseline exposed it: a newer Chromium rewrote
rgba(8, 18, 32, 0.62)as#0812209e, a Tailwind migration reformatted a font list'scomma spacing — and the diff flagged every one as a difference, drowning the review in
changes that aren't changes and blowing the report up to hundreds of MB. A green flickered
red purely across browser/build versions.
The diff now compares by a canonical form: colours parse to one
rgba()(hex /rgb/rgba/hsl/hsla, short + long hex, comma + modern space syntax), and comma/whitespaceruns normalize outside quotes. Captures become serialization-independent — the root fix
for re-baseline noise, at the diff, not the report.
Safety bar — only provably-equal values collapse. An unparseable value (or anything
inside a quoted string) is left byte-for-byte, so a real change always still surfaces. The
report shows the real captured strings; only the equality test is canonical. Custom props
stay ignored; content/text diffs stay exact.
Proof (required)
Screenshots Not applicable — diff-logic change, no browser surface. Receipts in
test/canonicalize.test.mjs:Full suite 255/255 — no existing diff test regressed (nothing relied on treating a
re-serialization as a change). build / typecheck / lint / format:check clean.
Checklist
build && typecheck && lint && format:checkpass ·npm test255/255test/canonicalize.test.mjs· Updated CHANGELOG ([3.15.0])