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… it to NaN
Percentage::from_calc returned Percentage { v: NaN } for anything that
is not a plain value. Adding a number, or a math function that was not
reduced, to a percentage then gave NaN, which is printed as 0 and, in a
color channel, as `none`:
opacity: calc(50% + 1) printed opacity:0
rgb(calc(10 + 10%) 0 0) printed #000
oklch(from #ff876a calc(l - .08) c h) printed oklch(none .152244 34.675)
It now fails, like the Angle and Time impls next to it. What a failure
means depends on the reader:
- A style declaration and a @font-face descriptor are left as written.
- A keyframe with such a selector is dropped, as a browser drops it.
- A typed `initial-value` of @Property has no unparsed form, so the rule
is an error: `Unexpected token: calc(`.
- Bun.color() returns null.
The color model stores the keyword `none` as NaN. The channel readers returned a calc() result as is. So a calculation that is NaN was printed as `none`, color-mix() filled it in from the other color, and the comma syntax of rgb() and hsl() did not parse. CSS Values 4 says that such a calculation is 0. censor_nan now wraps what the readers return for a value: the six literal results of ComponentParser and the five calc results of RelativeComponentParser. The `none` branch still returns NaN. asin(), acos() and atan() lost their <angle> type when the result was NaN: parse_trig returned a plain number. A <number> channel then took `asin(2)` as 0, where a browser rejects the color. parse_trig now keeps the angle. A hue folds it to 0. A <number> channel leaves the color as written.
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Updated 7:22 PM PT - Oct 21st, 2026
✅ @robobun, your commit f7ecd42af7691e49249f2bc367d94953a5916327 passed in 🧪 To try this PR locally: bunx bun-pr 45971That installs a local version of the PR into your bun-45971 --bun |
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Status: closed, not merged. One part landed in #47025 (7942008): the How to reproduce (main at 7942008, after #47025): /* b.css */
a { color: lab(50% calc(sqrt(-1)) 0); background: rgb(calc(NaN), 0, 0) }
b { color: color-mix(in lab, lab(50% calc(NaN) 0), lab(50% 40 0)) }With the last commit of this branch (f7ecd42, on an older main): Chrome 153 computes PR: #45971 |
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No actionable comments were generated in the recent review. 🎉 ℹ️ Recent review info
WalkthroughCSS calculation conversion now rejects unsupported percentage calc forms and attempts angle conversion for NaN inverse-trigonometric results. Color parsing converts parsed NaN components to zero while preserving explicit ChangesCSS calculations and colors
Suggested reviewers: Priority: ⬇️ Low Merge Risk: ⚪ Minimal · up to
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| Check name | Status | Explanation |
|---|---|---|
| Title check |  |
The title clearly and concisely states the main change: CSS color-channel NaN calculations now read as 0 instead of none. |
| Linked Issues check | |
Check skipped because no linked issues were found for this pull request. |
| Out of Scope Changes check | |
Check skipped because no linked issues were found for this pull request. |
| Description check | |
The pull request description is complete and relevant. It explains the problem, implementation, verification steps, performance impact, known limitations, and remaining browser differences. It does no… |
Full details: Description check
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Explanation
The pull request description is complete and relevant. It explains the problem, implementation, verification steps, performance impact, known limitations, and remaining browser differences. It does not use the exact template headings, but it provides the required information under equivalent sections.
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Beyond the inline findings, I also checked the parse_trig change (NaN asin()/acos()/atan() now typed as an angle, so opacity: asin(2) and width: calc(1px * asin(2)) are no longer folded to 0) and the Percentage::from_calc tightening (an unreduced number+percentage sum is now an error instead of a NaN percentage) — both match what Chrome does with those inputs, so they are not regressions. The relative parse_calc arm folding a calc() over a none origin channel to 0 follows the same top-level-calculation rule as the literal readers and is consistent with the rest of the change.
Extended reasoning...
The change touches the Rust CSS value parsers (calc.rs and color.rs): a NaN-to-0 helper applied at ten channel read sites, a tightened Percentage::from_calc, and an angle-typing change in parse_trig, plus WPT expectation updates and new minify/Bun.color test rows. No security-sensitive surface is involved. Four confirmed findings (class not fully covered at the comma-syntax none alpha, infinite origin hues in relative lch/oklch, mod/rem/round with infinite divisors now baked into a wrong color, and a typed @ property relative-color build break) are posted inline, so a human look is already indicated.
Findings marked 🟡 are optional suggestions and need no follow-up push.
Additional findings (outside the current diff — GitHub can't attach inline comments there):
-
🟣
src/css/values/color.rs— Users writingrgba(12, 34, 56, none)still get#fff0(opaque-white channels, zero alpha) after this PR, a color unrelated to the input; the base prints the same. The PR censors thecalc(NaN)sibling at this reader but leaves thenonearm at src/css/values/color.rs:1967 returning NaN intoparse_legacy_alphaat color.rs:1469. The NaN alpha then takes theFloatColor::Rgbpath at color.rs:1455 with legacy 0-255 channels stored into the unit-rangeSRGB, which clamp to 1.0. Fix: the comma syntax must rejectnonein every slot (browsers do); gateis_legacy && alpha.is_nan()to Err alongside the g/b check at color.rs:1238, or disallownoneinparse_legacy_alpha.Why this was flagged
Trigger: a stylesheet or
Bun.color()input with the legacy comma syntax andnoneas the fourth argument:rgba(12, 34, 56, none).parse_rgb_componentsat src/css/values/color.rs:1191-1240 rejects NaN in the g and b legacy slots (color.rs:1238) butparse_legacy_alphaat color.rs:1469 passes the alphanonearm (color.rs:1967, still NaN) through.clamp(0.0, 1.0), which keeps NaN. At color.rs:1448 the NaN alpha sends the color toFloatColor::Rgb(SRGB { r: 12.0, g: 34.0, b: 56.0, alpha: NaN }), where r/g/b are the legacy 0-255 rounded values but SRGB expects 0-1, so the printer clamps them to 1.0 and emits#fff0. A browser rejects the declaration, so the correct output is to leave it as written. The PR fixesrgba(12, 34, 56, calc(NaN))at the same site but not itsnonesibling. Remedy: in the legacy branch treat a NaN alpha like a NaN g/b (return Err at color.rs:1238).Verification: Pre-existing, acknowledged in the diff; no test in the PR pins the case.
parse_legacy_alpha(src/css/values/color.rs:1466-1472) passes the untouchednonearm (color.rs:1965-1967) through as NaN; at color.rs:1448!alpha.is_nan()fails, so the 0..255 channels are boxed into the unit-rangeSRGB(color.rs:1455-1460) and print#fff0. The base fails by the same route. -
🟣
src/css/values/color.rs— Relative lch()/oklch() colors whose origin hue is infinite still printnonefor a channel keyword, so the PR's new rule (a NaN channel is 0) is not applied across the whole class.from.components.2.rem_euclid(360.0)at src/css/values/color.rs:1358 turns an infinite origin hue into NaN after the readers' censor already ran, andparse_identat color.rs:2101/2136/2166/2192 returns that NaN uncensored, solch(from lch(50% 10 calc(infinity * 1deg)) l c h)printslch(50% 10 none)while a literallch(50% 10 calc(NaN * 1deg))now prints 0. Fix: censor or clamp the NaN produced by the hue normalization at color.rs:1358 (and the same step for every hue-bearing space) so a non-noneorigin never becomesnonedownstream.Why this was flagged
Input: a relative color whose origin color's hue is an infinite calculation, e.g.
lch(from lch(50% 10 calc(infinity * 1deg)) l c h)or the oklch sibling, parsed through parse_lch at src/css/values/color.rs:1348. The origin hue reader at color.rs:1987 applies censor_nan to +inf, which is not NaN, so inf is stored; color.rs:1358 then computesinf.rem_euclid(360.0), which is NaN, and the< 0.0fixup at color.rs:1359 does not catch it. parse_ident at color.rs:2204-2213 returns that NaN unchanged for the bare keywordh, and the color printsnonefor the hue, which color-mix() then treats as a missing channel. The base branch behaves the same, which is why the finder let it go, but the PR's stated rule is that a NaN that was not written asnonereads as 0, and its own censor sits before the step that manufactures this NaN, so the class fix is incomplete at this sibling site. Remedy: censor (or clamp to the max finite value per css-values-4 top-level-calculation) at color.rs:1358 so an infinite origin hue normalizes to a finite number.Verification: Pre-existing (the base prints the same
nonefor this input), but an uncovered sibling site of the class this PR sets out to fix. Trigger: a relative lch()/oklch() whose origin hue is infinite. color.rs:1358rem_euclid(360.0)turns inf into NaN after the readers' censor already ran;parse_identreturns it with nocensor_nan, sowrite_component(2648-2651) printslch(50% 10 none).
| } | ||
| Err(i.new_custom_error(css::ParserError::invalid_value)) | ||
| }) { | ||
| return Ok(value.v); | ||
| return Ok(censor_nan(value.v)); |
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🔴 A stylesheet whose typed @ property initial-value holds a valid relative color such as oklch(from #ff876a calc(l - .08) c h) now fails the whole bundle; on the base branch it built. RelativeComponentParser::parse_percentage wraps the channel keyword as a Percentage (color.rs:2172), so calc(l - .08) becomes a percentage+number sum that Percentage::from_calc now rejects (calc.rs:1615). @ property has no unparsed fallback and error_recovery is never true. Fix: read the keyword as the spec's (l for oklab/oklch, l*100 for lab/lch/hsl/hwb) and scale back, so calc(keyword +/- number) reduces in every percentage-only channel reader; Bun.color() also returns null for these inputs. [also at: src/css/values/calc.rs:1615 - Bundling a stylesheet whose typed @ property initial-value is a valid relative color like hsl(from blue h s calc(l + 20)) now fails with "Unexpected token: hsl("; on the base it built.]
Why this was flagged
Input: @ property --p { syntax: "<color>"; inherits: false; initial-value: hsl(from blue h s calc(l + 20)); } or the oklch form above, both valid CSS (css-color-5: the l keyword is a , Chrome accepts them). The relative arm at color.rs:2169-2183 builds Calc::Value(Box::new(Percentage { v })) for the keyword (color.rs:2172), so Calc::add at calc.rs:264 calls rhs.into_value() on the Number term, and Percentage::from_calc now returns Err(invalid_value) (calc.rs:1615). The literal fallback at color.rs:2009 cannot parse the keyword either, so the color errors. For a color: declaration this is caught as an unparsed property, but @ property propagates the error (src/css/rules/property.rs:141), error_recovery is only ever false (css_parser.rs:2952), and the stylesheet parse returns Err at css_parser.rs:2627, which the bundler reports as a bundle error. On the base branch from_calc folded the sum to Percentage { v: NaN }, so the rule built (with a wrong none channel).
Verification: RelativeComponentParser::parse_percentage (src/css/values/color.rs:2169-2172) wraps l as Calc::Value(Box::new(Percentage { v })). Calc::add at calc.rs:258-265 calls Percentage::from_calc, changed to Err(invalid_value) (calc.rs:1612-1616). PropertyRule::parse has no fallback at src/css/rules/property.rs:141, and error_recovery is only ever false (css_parser.rs:2952). On the base the same input built.
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Same root as the thread on #45970: the error comes from Percentage::from_calc, which is the first commit of this stack.
- The fix named here, the keyword as a
<number>, is css: fold relative colors on the scale of their function, and keep them as written when the fold is not exact #45362 (commit b7ea982). - The fallback for a typed
@propertyis css: keep a typed @property initial-value as written when no component matches #45807.
I did not copy either into this PR. #45970 now says to land #45807 first, and its tests assert the as-written output for the valid value in a test.todo row. I leave this thread open for a maintainer.
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Update after 1382c23.
- css: keep a typed @property initial-value as written when no component matches #45807 is closed. Its change is now part of css: read an @property initial-value on the stylesheet's parser, keep an unmatched value as written #45806, which is open.
- The typed
@propertyrows of css: fail a percentage calc that cannot be reduced instead of folding it to NaN #45970 are now onetest.todothat asserts the value as written. On a local merge of this branch with css: read an @property initial-value on the stylesheet's parser, keep an unmatched value as written #45806, that test passes.
This thread stays open for a maintainer.
`hsl(from blue h s calc(l + 20))` is valid CSS. The rows asserted `null` from Bun.color() and a build error from a typed @Property for it. They are now todo tests that assert the correct result. The row for the invalid `rgb(calc(10 + 10%) 0 0)` stays. The test comments say what each row is. They no longer say what the row printed before.
The comments no longer say what a row printed before.
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The two findings outside the diff are on main too. This PR does not change them, and Notes now lists both under "Still different from a browser after this PR".
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Code review found no new issues
No new issues were found in this update; 1 finding from earlier reviews is still open above.
Still open from earlier reviews (1):
- 🔴
src/css/values/color.rs:2182—A stylesheet whose typed @ property initial-value holds a valid relative color such as oklch(from #ff876a calc(l - .08)…
If you have decided not to act on one of these findings, resolve its thread (a reply alone leaves it open) and the next review stops counting it. To review this commit again now, use Re-run on its "Claude Code Review" check.
…not reduced A typed `initial-value` that is not reduced is an `Unexpected token` error, because `SyntaxString::parse_value` has no unparsed form. The rows asserted that error. #45806 keeps such a value as written, so the rows failed on a merge with it. They are now todo rows that assert the value as written, next to the two rows for valid values. Without #45806 the todo test fails with the error. With #45806 it passes. The file passes in both cases. The comment pointed to #45807. That change is now part of #45806.
…literal-color-calc-nan
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Code review completed
Nothing new to post: everything this review found is already covered by existing comments on this pull request or didn't merit a separate one.
Still open from earlier reviews (1):
- 🔴
src/css/values/color.rs:2182—A stylesheet whose typed @ property initial-value holds a valid relative color such as oklch(from #ff876a calc(l - .08)…
If you have decided not to act on one of these findings, resolve its thread (a reply alone leaves it open) and the next review stops counting it. To review this commit again now, use Re-run on its "Claude Code Review" check.
…literal-color-calc-nan
### What does this PR do? Consolidates the open pull requests on the CSS parser (`src/css`: parsing, minifying, lowering, printing, CSS modules) into one. 179 open pull requests were in scope. Each was judged by one rule: **the output must mean to a browser what the input meant.** Every claim was run through a build of `main`, a build with the change, lightningcss 1.33 and Chromium 156 (CSSOM, computed values, painted pixels for colors and gradients), and counted against 10,116 real stylesheets: the published CSS of about 190 popular npm packages, plus stylesheets from open source repositories. 107 land here, whole or in part, most of them cut down. The source diff is net negative. Of the 10,116, 9,509 are stylesheets that someone ships. The rest are test fixtures of other tools (521), Tailwind v4 source that needs its plugin (59) and SCSS, PostCSS or template source (27). | 9,509 shipped stylesheets | `main` | this branch | |---|---|---| | fail to build | 71 | 35 | | ... of those, valid CSS that Bun rejects | | 0 | | minified output reads differently in Chromium than the input | 552 | 2 | | CSS modules with a name that is referenced but not defined, or exported but not defined | 166 | 0 | | all 10,116 | `main` | this branch | |---|---|---| | fail to build | 192 | 141 | | minified output reads differently in Chromium than the input | 593 | 15 | | build on `main`, fail here | | 0 | | right on `main`, wrong here (minified, and at the default targets) | | 0 | | size of the minified output, no targets | 162.32 MB | 162.47 MB (+0.093%) | | size of the output at the default targets | 224.1 MB | 210.2 MB (-6.2%) | A syntax error is a build error, with one exception: the IE star hack `*zoom: 1` is skipped, because tachyons and handsontable ship it. The 35 shipped stylesheets that fail are invalid CSS: 28 have a selector that Chromium drops (semantic-ui-css, swiper, @ionic/core, Adobe Spectrum, xp.css), 2 an `@import` after other rules, and one each `@supports not X and Y`, a nested `@keyframes`, a stray comma, a selector list in `::slotted()`, `@media screen\0` (govuk-frontend). The 2 that read differently fold a `color-mix()` inside a gradient (see the known gaps). The growth of the minified output is rules and declarations that `main` deleted by mistake: 87 KB of rules, 45 KB of prefixed declarations that only browser targets can rule out. #### Popular CSS that `main` breaks today - normalize.css, modern-normalize, sanitize.css: `font-family: monospace, monospace` is collapsed to `monospace`, which changes the font size from 16px to 13px (#46662). - CKEditor 5, Tabler, Carbon, VitePress, Ionic, PatternFly, Excalidraw: a rule of custom properties is deleted as a "duplicate" of a later rule with the same selector and other custom properties. 37 stylesheets lose 1,681 custom properties (#33684). - Material Components, daisyUI, DocSearch, plyr: a `var()` size loses to its own fallback (#42101). - nextra, daisyUI, CKEditor: declarations written after a nested rule are moved above it (#45462). - antd 4, purecss, govuk-frontend: browser hacks in selector lists start to apply everywhere (#42100). - foundation-sites, flatpickr, 98.css, blueprintjs, scalar, react-datepicker: the build fails on valid CSS (#46756, #38552, #38534). tachyons, handsontable: it fails on the IE star hack (#46751). - nodejs.org, Mantine: a CSS module exports classes that no rule defines, because the `@apply` or `@mixin` in them is moved out of the rule (#46759). - hint.css and 42 more: `z-index: 1000001` and `1000000` become the same number (#46715). - Adobe Spectrum: `--version: 5.0.1` prints as `5.1`. - A quarter of all stylesheets: minified output has a stray space in `align-items: center` (#41993). #### Behavior changes to look at first 1. **`light-dark()` is kept as written at the default browser targets** (#42009). The lowered form `var(--buncss-light, a) var(--buncss-dark, b)` is invalid unless a compiled `color-scheme` covers the element: 184 of the 215 real stylesheets that get it never define the variable, so every browser drops the declaration. The docs section on the polyfill is removed. 2. **`border` is not built from longhands** (#42072): `border-width:0;border-style:solid;border-color:red` stays three declarations, because `border` also resets `border-image`. 305 real stylesheets grow by 30 KB in total; `bootstrap.min.css` by 113 bytes, 5 gzipped. No real stylesheet was found where the old merge shows, so this is the one to drop if size matters more. 14 existing expectations change. 3. **A CSS module no longer exports names that only occur inside `:global(...)`** (#45487). 73 real modules lose 202 export keys, all of them names that no rule has. `import { g }` or `composes: g` of such a name becomes a build error. 4. **Container names and `@counter-style` names stay global in a CSS module** (#45247 by @mikamikasuki). `main` hashes the `@container` name but not `container-name`, so a named query never matches. postcss-modules (Vite, css-loader, Next.js) keeps them global; lightningcss and esbuild hash both. Global keeps a container that is queried from another file or from JS working. 5. **Syntax errors are build errors, also two that `main` lets through**: a media query that stops short (`@media screen and {`, `@media not {`, `@import "a.css" screen and;`) and `@media (width <) foo {`. No stylesheet of the 10,116 has either. A condition that is valid by the grammar though no browser knows it, `( ... )` or `fn( ... )`, is kept as written (#46756): `(min-width:0\0)`, `(not(hover))`. 6. **Declarations after a nested rule stay where they were written**, as a nested declarations rule (#45462). Changes the output of 199 real stylesheets; in a fuzz of 2,850 nested programs compared by computed style, `main` was wrong in 1,056 and the pull request's code, before it was trimmed here, in none. 7. **`Bun.color`**: `color()` inputs are converted instead of returned as a string (`Bun.color("color(srgb 1 0 0)", "hex")` was `"color(srgb 1 0 0)"`); `currentColor`, system colors and `light-dark()` give `null` in the converting formats instead of the keyword as a string; a relative color or `color-mix()` outside sRGB is clipped, not gamut-mapped (`hsl(from oklch(100% .399 336.3) h s l)` is `#ff5bff`, was `#fff`). 8. The `:-moz-any()` and `:-webkit-any()` copies of rules with `:is()` are gone at the default targets (#45945, #42029). The `:-webkit-any()` copy outranked the original rule: `.title{color:blue} :is(h1,h2,h3){color:red}` painted red. 5.8% of all default-target output was the `:-moz-any()` copies. 9. `Property` grows from 216 to 224 bytes: `Url` stores its text as a slice so that two `url()` values can be compared (#46895). The pull request packed a pointer and a `u32` behind `unsafe` to avoid that. #### Not in this PR, needs a decision - **Raise the default browser targets (#40369) and add a `cssTarget` option (#40368).** Today: Chrome 80, Edge 80, Firefox 78, Safari 14, Opera 67, and no public way to change them. At Vite 8's floor the output of the 9,924 stylesheets is 15.3% smaller (3.9% gzipped). About a dozen fixes here only matter at today's floor, and code for older targets is unreachable without the option. - Vendor prefixes for `user-select`, `appearance`, `hyphens` and five more (#45814): 1,116 real stylesheets lack a prefix they need at the default targets. And for `backdrop-filter` (#44648): 173. - Clip instead of gamut-map in the sRGB fallback of a plain wide-gamut color: deletes about 90 lines, changes every pinned fallback hex. If the mapping stays, #44647 by @oddharsh makes it closer to what browsers paint (colors off by 2/255 or more: 168 to 110 of 3,170 real ones). #### Changes **Rules: duplicates, merging, nesting, fallbacks** - The `:-moz-any()` copy of every rule with `:is()` or `:not(a, b)` is gone: Firefox 78 has `:is()` (#45945). 1,164 real stylesheets - Keep declarations written after a nested rule in place with a nested declarations rule (#45462). 379 real stylesheets - With nesting compiled away, an unknown at-rule inside a style rule was moved out of it: `.wrapper{@apply flex}` printed a bare `@apply flex;` and the rule was gone, so a CSS module exported a class that no rule defines. It now stays in a block under the compiled selector. 72 real modules with Tailwind's `@apply`, 25 with Mantine's `@mixin` (#46759). 316 real stylesheets - Keep !important in the rules generated for logical properties and color-scheme (#38597). 311 real stylesheets - With browser targets, remove an earlier duplicate rule only when its declaration block is equal (#46861). 171 real stylesheets - Compare custom property names in `PropertyId` equality and importance in duplicate-rule detection (#33684). 40 real stylesheets - Keep same-condition @supports rules and empty named @layer blocks (#46733). 31 real stylesheets - Keep target-added vendor prefix passes on cloned and re-minified rules, and never print a bare `:full-screen` (#43339). 12 real stylesheets - Keep the selectors on rules added for color fallbacks and logical properties (#43240). 3 real stylesheets - A later declaration of a property drops the `@supports` color copies of the earlier one, which printed after the rule and won (#45560). 2 real stylesheets - Do not merge style rules in a stylesheet that holds `revert-rule` (#46953). 1 real stylesheets - `@import ... supports(-webkit-mask: none)` kept its prefix (#38589) **Properties and shorthands** - Print align-items:center without a stray space when no safe/unsafe keyword is given (#41993). 3,317 real stylesheets - Emit the physical longhands instead of the inset shorthand for targets without it (#38583). 1,452 real stylesheets - Keep the stops of an upward gradient as written, and drop a `50%` hint only at the midpoint (#46790). 104 real stylesheets - Emit unparsed border-block-* declarations when compiling logical borders (#38582). 89 real stylesheets - Keep repeated font families and dedupe only the inserted system-ui fallbacks (#46662). 88 real stylesheets - A `width` / `height` / `min-*` / `max-*` with `var()` or `env()` was printed before the plain fallback written above it, so the fallback won (#42101). 26 real stylesheets - Keep box-orient and box-direction when flex-direction or flex-flow follows (#45672). 16 real stylesheets - Write held prefixed background declarations at every flush (#46882). 6 real stylesheets - Derive equality for Size2D and BorderRadius, and keep every prefix in the border-radius handler (#45665). 2 real stylesheets - Print `none` instead of an empty border-image, mask-border or mask-box-image value (#45143). 2 real stylesheets - Keep font/transition sub-properties on the side of the shorthand they were written on (#41990). 2 real stylesheets - CSS-wide keywords are not names: `font:12px Arial;font-family:inherit` printed `font:12px inherit`, `color-scheme:inherit` and `color-scheme:auto` printed `normal`, `transition-property:unset` was folded into `transition` (#42022). 2 real stylesheets - Only fold font longhands into `font` when the rule declared a `font` (#45459) - Keep a font family name quoted when its identifiers do not read back as the same name (#46606) - Stop rewriting valid positions into ones browsers reject (#45197) - `border` is no longer built from longhands unless the rule also sets what `border` resets (`border-image`), and an author's `border-image` reset is no longer dropped. `transition` is likewise only written where the rule wrote one, because it resets `transition-behavior` (#42072) - `border; border-image: <gradient>; border-image-slice: 1` lost the gradient in every default build (#42018) - A prefixed `linear-gradient` keeps its direction, written or generated: the prefixed syntax names the starting side and measures angles differently (#46697) **At-rules** - Print @font-face format() keywords as strings (#37979). 439 real stylesheets - Print @supports `not` conditions without a leading space (#38559). 88 real stylesheets - Reset after the number token of a unicode-range (#45835). 33 real stylesheets - Keep `<general-enclosed>` media and container conditions as written (#46756). 24 real stylesheets - A strict range such as `(width < 768px)` lowered for old targets still matched at exactly 768px. The step is now `.02px`. The `not all and` form for other units is not taken (#46806). 18 real stylesheets - Keep scanning an @supports condition after a nested block (#38552). 9 real stylesheets - Every `@counter-style name` printed as `@counter-stylename`, which browsers drop (also #46692). In a CSS module the name now stays global, like the `list-style` that refers to it (#33679). 9 real stylesheets - Keep a keyframe whose block has an invalid item (#46288). 2 real stylesheets - Read an @Property initial-value on the stylesheet's parser, keep an unmatched value as written (#45806). 2 real stylesheets - `@media {}` is `all`. A media query that stops after `and`, `or` or `not` (`@media screen and {`) is a build error; `main` printed `not all` or dropped the condition, silently. The `@layer` and type selector parts are not taken (#46869). 2 real stylesheets - Accept a name-only `@container` and a `style()` feature with no value (#46689). 1 real stylesheets - Parse `<timeline-range-name> <percentage>` keyframe selectors (#45652) - Allow `or` inside parentheses after a media type (#45088) - Print the `=` comparison in media and container queries as `=` (#45071) - Parse the @font-palette-values font-family descriptor as a list of family names (#45484) **Selectors** - Never wrap a selector list in :is() (#46787). 414 real stylesheets - Stop emitting :-webkit-any() copies of :is() that outrank the original rule (#42029). 373 real stylesheets - With browser targets, a selector list with a vendor-prefixed member was split, which revives hacks that rely on other engines dropping the whole list: `.s *::-ms-backdrop,.s{flex:auto}` applied everywhere. Rewritten; the list is printed as written (#42100). 42 real stylesheets - Print the vendor prefix on downleveled :any-link, :read-only, :read-write, :placeholder-shown and :autofill (#42131). 12 real stylesheets - Fix nesting lowering of a `&` that does not lead its selector (#43047). 8 real stylesheets - `@scope`: `&` and implicit selectors compile to `:where(:scope)`, relative selectors and bare declarations parse (#43165). 7 real stylesheets - Only reject bare :global / :local pseudo-classes in CSS modules (#38534). 5 real stylesheets - Stop truncating `@scope to (...)` and stop replacing `&` in the scope-end selector (#43146). 2 real stylesheets - `[xl|href$=".pdf"]` lost its namespace prefix (#45159). 2 real stylesheets - Match An+B keywords exactly and take only `+` as the leading sign (#42953). 1 real stylesheets - Parse ::details-content and ::picker() like ::part() (#45504). 1 real stylesheets - Parse :window-inactive as an ordinary pseudo-class, and accept it after ::selection (#45815) - Print :nth-col(1) and :nth-last-col(1) in functional form (#41575) - `li::before::marker` failed the build (#45810) - `&` inside `:nth-child(... of S)` is resolved when nesting is compiled away. The second selector serializer (326 lines) is deleted (#43024) **Colors and `Bun.color`** - Keep light-dark() as written under the default browser targets (#42009). 227 real stylesheets - Number and percentage channels parse in `lab()`, `lch()`, `oklab()`, `oklch()`, `hsl()` and `hwb()`; the hue of `lch` / `oklch` is no longer scaled by alpha (#45084). 130 real stylesheets - `Bun.color` returns `null` for `currentColor`, system colors and `light-dark()` in the converting formats, instead of the CSS keyword as a string (#33047). 130 real stylesheets - Relative colors: channel keywords are on the scale of their function (`rgb(from #369 calc(r + 10) g b)`), the origin's alpha is kept, a relative color kept as written gets no `@supports` copies, and a result outside sRGB is not folded (#45362). 31 real stylesheets - Keep rotate: 0deg out of none, and keep the origin alpha in relative colors (#38486). 13 real stylesheets - Compute the D50 reference white in f32 so greys convert to lab(l 0 0) like lightningcss (#38535). 7 real stylesheets - Return a missing hue for a grey from conversions into lch, oklch, hsl and hwb (#45201). 5 real stylesheets - Fix color(a98-rgb), srgb-linear relative colors and color-mix(in xyz-d50) (#38487). 4 real stylesheets - Match named colors without regard to ASCII case (#45092). 3 real stylesheets - Fold min(), max() and clamp() over plain numbers (#39515) - `calc(l - .08)` in a percentage channel of a relative color became NaN and printed `#000` (also #45970) (#45971) - Bun.color: convert color() inputs instead of returning them as a CSS string (#38488) - A `color-mix(in srgb, ...)` result outside sRGB prints `color(srgb ...)` instead of a gamut-mapped hex (#39269) **`calc()` and numbers** - Rounding to 6 significant digits ate into the integer part: `z-index:2147483647` became `2147480000`, `max-width:9999999px` became `10000000px`, `--x:1234567.5` became `1234570`. It now only cuts a fraction short: a value kept as tokens prints its source text, a typed value prints every integer digit and at least one digit of the fraction (#46715). 43 real stylesheets - A number without a unit is no longer repaired into `px` (`height:1.5715` is dropped by a standards-mode browser, so it prints as written), `calc(-1 * 0)` is not a length, and on a property of the range [0,∞] (sizes, border radii, padding, border and outline widths, gap, `flex-basis`, `font-size`) a `calc()` that folds below zero prints `0` instead of an invalid negative literal, and a negative literal no longer replaces the valid declaration before it (`width:10px;width:-5px` printed `width:-5px`) (#42104). 24 real stylesheets - Print numbers from the f32's shortest digits, not its f64 expansion (#38565). 17 real stylesheets - Print negative numbers below 1 with a single minus sign (#38516) - Keep math functions over two different length units as written (#38489) - Fold rem() with a truncated quotient, so it keeps the sign of the dividend (#32286) - A one-argument `min()` / `max()` around a sum printed without any function (`width:100% - 20px`) (#46145) - `round()` breaks ties upward and handles a negative step as browsers do (#45249) **CSS modules** - A CSS module exports its `@keyframes` names (`styles.spin`). Hashing is unchanged (#46720). 145 real stylesheets - A name inside `:global(...)` prints plain but was exported as `name_<hash>`, a class no rule has (also #38573) (#45487). 90 real stylesheets - Keep container names global in CSS modules (#45247). 6 real stylesheets - Tag the keyframes name when an `animation` value falls back to raw tokens (#46034). 6 real stylesheets - In a plain stylesheet `composes: a from "./b.css"` was treated as an import: the file was inlined and an absolute path printed (#45961). 4 real stylesheets - Drop a rejected composes instead of failing the file at print time (#38538). 1 real stylesheets - Keep every rule's custom properties for the composes conflict check (#38523) - Keep composes working after a nested rule in the same block (#38520) - `IdentOrRef::hash` read 2 of 16 bytes, so in release builds every class of a module hashed alike (#30784) **Tokens, `url()`, diagnostics** - The block skip stack no longer allocates on every block exit (#39533) - Report the diagnostic's line without its line breaks in position.lineText (#38342). 192 real stylesheets - Compare `url()` values by their text (#46895). 26 real stylesheets - Values kept as tokens keep the blanks they were written with instead of having them re-invented at print time: `attr(x type(<number>))` printed `type(< number> )`, which browsers drop. Minified output still drops the blanks that cannot matter (#45577). 19 real stylesheets - The IE star hack (`*zoom:1`) failed the whole build. The declaration is skipped, as every browser does. It is the one syntax error that builds: tachyons, handsontable and jasmine ship it (#46751). 8 real stylesheets - The path of a copied asset spliced into `url()` is always quoted, so a file name with a space or a parenthesis cannot end the `url()` (#41557). 7 real stylesheets - Move the skip loop of parse_until_before out of the generic body (#39520) - Remove dead code from bun_css: the unused `impl Default for Property` (#45618) - Default the at-rule and qualified-rule parser traits, drop the url_to_css shim (#31999) **Speed** Four inputs that took quadratic or exponential time, or produced output out of proportion, are now linear, with no new limit and no extra pass (#31639, #42243, #38531, #43421). **Tests only** - `css-fuzz.test.ts` never ran in CI and timed out on debug builds; it is a deterministic table now (#38500) - `nth-anplusb-ident.test.ts` counts heaps in a child process (#46331) - `color.test.ts` checks the ansi-16 sweep with one `expect()` (#42824) - Not CSS, but it failed this PR's CI and fails on `main` too: `ws-proxy.test.ts` on Windows, "a message sent during a TLS renegotiation arrives after it". The helper server now renegotiates from the callback of the frame's write (#46170) **No pull request covered these** - `--v: 5.0.1` printed as `5.1`, `--w: 1.0.0` as `10`, `--x: 1+2` as `12`, `2n+1` as `2n1`: a number token that touches another keeps its source text. - `color-scheme: auto` printed as `normal`, and `color-scheme: dark light` as `light dark`. - A bare `:global` or `:local` in a CSS module sets the scope of the names after it, up to the end of the selector, as in css-loader. It was a build error. - The scrollbar states (`a:horizontal`, `::-webkit-scrollbar{&:horizontal{}}`) are valid in a plain compound, as in WebKit and Blink. - Without browser targets, `-webkit-box-align`, `-ms-flex-align` and the like were dropped next to their standard form (flatpickr, foundation-sites, materialize-css: 28 stylesheets), and `-webkit-fill-available` before `-moz-available` (beercss). - `(-o-min-device-pixel-ratio: 2/1)` printed as `2`. - `sin()`, `cos()` and `tan()` are exact at multiples of 90deg: `calc(100px * cos(90deg))` printed `-.00000437114px`. - A `display-p3` color at targets that have P3 but not the other `color()` spaces (Safari 10.1 to 14) got itself as a fallback. - `width: rem(-18px, 5px)` folds to a negative literal once `rem()` is right; it prints `0`. - Consecutive nested declarations rules, which arise when same-query `@media` blocks in one rule merge, are folded into one and count against the existing selector expansion limit as the `&{}` rules they replace did. #### Known and not fixed here - Four longhands are still folded into a `transition` the author did not write where the targets add a prefixed copy of a property (`mask-image` at Chrome 80): only the shorthand gives the copy its own times. - A later `background`, `box-shadow` or `border-*` declaration still loses to the `@supports` copy of an earlier `var()` value of the same property with a wide-gamut color. Same on `main`; #45560 is taken for the properties of the fallback handler and for unparsed values only. - A merged rule prints the unprefixed name in the passes of the rule it absorbed: `.d::-webkit-input-placeholder{}.d::-moz-placeholder{}` prints `::placeholder` for the second (#42106, not taken: it breaks the merge of prefix-equivalent rules). - The `border`, `outline` and `font` shorthands, `line-height`, `scroll-padding`, `background-size` and a few more still print a `calc()` that folds below zero as a negative literal. No real stylesheet has one. - `all` is not a property Bun knows, so `a{margin-top:1px;all:unset}` prints `all` first. Same on `main`. - A selector kept as raw tokens loses the blank before `*` when minified: `--sel: .dark *` prints `.dark*`. Same on `main`. - `width:calc(0% + 12px)` folds to `12px`, which lays out differently in a table cell. Same on `main`. - The `:dir()` / `:lang()` rules of a lowered logical property print before the nested rules of their rule, so a logical declaration written after a nested rule of equal specificity still loses to it. Same on `main`. - A fraction is still rounded to 6 significant digits (`12345.678` prints `12345.7`, `33.3333333333%` prints `33.3333%`). Keeping every digit would add up to 282 KB over the corpus. - `@keyframes "quoted"` is hashed in a module but not exported. - In a module, a keyframes name inside a `var()` fallback is not hashed: `animation: var(--enter, fade 1s)`. Same on `main`. - A `color-mix()` or relative color folded to a hex inside a gradient changes the interpolation from Oklab to sRGB (VS Code, clawhub). Printing `color(srgb ..)` instead needs a fallback for `mask-image`, `list-style-image` and custom properties at the default targets, which have none. - A comma list in `@container` still fails the build. - After a bare `:global`, names that are hashed at print time (`::view-transition-old(foo)`) are still hashed; inside `:global(...)` they are not. #### Pull requests in scope that do not land here - Duplicates of a pull request that lands here: #36961 (of #37979), #38478 (of #46662), #38480 (of #46733), #38482 (of #46715), #38491 (of #38500), #38508 (of #45201), #38513 (of #45362), #38573 (of #45487), #38640 (of #38500), #45525 (of #45247), #45589 (of #46756), #45970 (of #45971) - Already fixed on `main`: #38674 - Right, but for input nobody writes (0 of 10,116 stylesheets, and not new syntax): #31916, #38526, #38592, #39349, #41139, #41801, #42042, #42484, #43078, #45604, #45908, #46086, #46221, #46224, #46273, #46694, #46707, #46737, #46755, #46816, #46870, #46934 - Right or harmless, but not worth their code, their bigger output or the behavior they change: #30905, #31924, #33332, #34426, #36225, #38006, #38512, #38547, #38551, #38561, #38572, #38576, #38607, #38623, #38667, #38692, #42106, #42912, #42918, #43407, #43434, #44700, #45442, #45546, #45747, #45759, #45825, #45946, #46061, #46127, #46206 - Need a decision (see above), stay open: #40368, #40369, #44647, #44648, #45814 - Stays open: #45787 Out of scope: CSS linking and chunking in the bundler, the dev server, docs-only pull requests, and repository-wide sweeps that touch `src/css` in passing. Thanks to @mikamikasuki (#45247), @alii (#39520, #31999) and @oddharsh, whose measurements on #40369 and #41990 were used. Fixes #16727. Fixes #24770. Fixes #30772. Fixes #44704. Fixes #45089. Fixes #45237. Fixes #46872. ### How did you verify your code works? - The 35 CSS test files pass on a debug build, also with `FORCE_COLOR=1`. 600+ of the tests in this branch fail on a build of `main`. An earlier head of this branch passed all 179 CI jobs that ran. - The reproduction of each issue listed above was run on `main` (wrong) and on this branch (right). - Differential run over the 10,116 stylesheets, `main` against this branch, minified without targets and through `Bun.build` at the default targets: no stylesheet that builds on `main` fails; Chromium 156 compares the output with the input rule by rule (CSSOM, then computed values on a sized element in a standards-mode document, colors as painted pixels in sRGB and P3). The comparison has 195 control pairs that must read equal or different. For stylesheets that read differently on both builds, mostly because of lowering, the sets of differences were compared; the three new ones are two minifier fixtures that are wrong on both and one comparison artifact. - CSS modules are checked for consistency instead, since hashed names defeat the comparison: every reference points at a name the output defines, every export exists. - `Bun.color`: 59 inputs in 13 formats on both builds; every changed cell was read.
Stacked on #45970.
Problem
lab(50% calc(sqrt(-1)) 0)printslab(50% none 0). WPT and Chrome give 0.noneis a missing component:color-mix()takes it from the other color.noneas NaN, and the channel readers (src/css/values/color.rs:1948) return a calculation as is.rgb(calc(NaN), 0, 0)stays unparsed, andBun.color()of it isnull: the comma syntax rejects NaN.Fix
censor_nanwraps the value results of the readers: six literal, five relative calc. Thenonearm still returns NaN.parse_trig(calc.rs:713) made a NaNasin()a plain number. It now keeps the angle, so a number channel rejectsasin(2)as a browser does.css.test.ts(50 rows fail on css: fail a percentage calc that cannot be reduced instead of folding it to NaN #45970 alone),color.test.ts(15),wpt/color-computed-rgb.test.ts(3). Alsotest/js/bun/css,test/bundler/css.Background
dtoa_short. The color printer writesnonebefore that.rotate: calc(NaN * 1deg)printsnone).Downsides
mod(),rem()andround()give NaN for an infinite operand. Main leftrgb(mod(1, infinity), 0, 0)as written. It now prints#000. Chrome computesrgb(1, 0, 0).lab()a and b: 3 of 6color-mix()rows differ there..text+0 B.Notes
What main prints, and what this PR prints
lab(50% calc(NaN) 0)lab(50% none 0)lab(50% 0 0)lab(50 0 0)lab(50% 10 0 / calc(NaN))lab(50% 10 0/none)lab(50% 10 0/0)lab(50 10 0 / 0)lch(50% 10 asin(2))lch(50% 10 none)lch(50% 10 0)lch(50 10 0)color(srgb calc(NaN) 0 0)color(srgb none 0 0)color(srgb 0 0 0)color(srgb 0 0 0)rgb(calc(NaN), 0, 0)#000rgb(0, 0, 0)rgba(12, 34, 56, calc(NaN))#fff0#0c223800rgba(12, 34, 56, 0)color-mix(in lab, lab(50% calc(NaN) 0), lab(50% 40 0))lab(50% 40 0)lab(50% 20 0)lab(50 20 0)lab(from lab(50% 10 20) l calc(a * NaN) b)lab(50% none 20)lab(50% 0 20)lab(50 0 20)lab(50% 0e999 0)lab(50% none 0)lab(50% 0 0)lab(50 0 0)lab(50% asin(2) 0)lab(50% none 0)rgb(asin(2), 0, 0)lab(50% none 0)lab(50% none 0)lab(50% none 0)lab(50 none 0)WPT
css/css-color/parsinghas the same rule:lab(calc(NaN) 0 0)islab(0 0 0)(color-computed-lab.html),hsl(calc(0 / 0) 100% 50%)isrgb(255, 0, 0)(color-valid-hsl.html),color(srgb calc(NaN) 0 0)iscolor(srgb 0 0 0)(color-computed-color-function.html), andrgb(calc(NaN), 0, 0)isrgb(0, 0, 0)(color-computed-rgb.html, "Red channel resolves NaN to zero"). The port of the last file intest/bundler/css/wpt/pinned the source text for those three rows. They now assert#000.What the review changed
CSSNumberFns::parse,Percentage::parseandAngle::parseintocolor.rsand censored in their calc arm. It is nowcensor_nanon the results, with the shared parsers called as on main.0e999token printednone. Both are 0 now.Percentage::from_calcis its own PR, css: fail a percentage calc that cannot be reduced instead of folding it to NaN #45970 (the first commit here).rgb(asin(2), 0, 0)was left as written on main, and the first version printed#000. A browser rejects it.parse_trignow keeps the angle, so it stays as written.mod(),rem()andround(): not fixed here, listed under Downsides.parse_trigoutside a color.asin(2),acos(2)andatan(NaN)now behave asasin(.5)does in every position.opacity: asin(2),line-height: acos(2)andwidth: calc(1px * asin(2))stay as written. Main printed0. Chrome rejects these declarations.rotate: asin(2)printsrotate:0rad, andlinear-gradient(asin(2), red, blue)printslinear-gradient(0rad,red,#00f). Main left them as written. Chrome computes0deg.asin(.5)now rejectsasin(2)too:@media (min-width: asin(2))isInvalid media query(main:(width>=0)), and a typed@propertywithsyntax: "<number>"andinitial-value: asin(2)isUnexpected token: asin((main:initial-value:0).@propertywithsyntax: "<angle>"andinitial-value: asin(2)builds now (0rad).Evaluator results that Chrome does not share. 57 expressions in
rgb(X, 0, 0)andlab(50% X 0), compared with Chrome 153. Bun gives NaN and Chrome gives a value for 8 of them:mod(1, infinity),mod(-1, -infinity),rem(1, infinity),rem(-1, infinity),rem(1, -infinity),round(up, 1, infinity),round(up, 1, -infinity)andround(down, -1, infinity). In the comma syntax main left such a color as written, and this PR folds the channel to 0. That changes the color for the 5 positive ones. The 3 negative ones clamp to 0 inrgb()in Chrome too. In the space syntax main printednoneor#000for them, so those rows were wrong before and are wrong now. One of the three evaluators has an open change for this: #45249 adds the infinite-step cases toround().rem()andmod()have none. #32286 changesrem()toa - b * trunc(a / b)for the sign of the result, and that is still NaN for an infinite B.Firefox 157 and WebKit (one run of the test rows in each, during the self-review). Firefox computes
lab(50 calc(NaN) 0)forlab(50% calc(NaN) 0). It also keeps the NaN in the hue oflch()andoklch()and in the a and b ofoklab(). For the threecolor-mix()rows with such a channel it computeslab(50 calc(NaN) 0), hue 90 and#80bf40, where this PR printslab(50% 20 0), hue 45 and#bf9f40. It computes 0 for the lightness, the chroma, the alpha,color(),rgb(), and the hue of a plainhsl()andhwb(). WebKit computes 0 in each row, as Chrome does.Probe. 921 rows on release builds. From #45970 to this PR, 329 rows change: 192 from
noneto 0, 82 comma-syntax colors from unparsed to parsed, 19 from#fff0to the real rgb with alpha 0, 20 withasin()oracos()in a number channel or the alpha that now stay as written, 11 with it in a hue that now give 0, and 5color-mix()folds. No row becomes an error.Still different from a browser after this PR
calc(0 / 0),calc(1 / 0),min(NaN, 1),max(NaN, 1)andclamp(0, NaN, 1)in a channel are not reduced, so the color stays as written.0e999as NaN outside a color channel.rgba(12, 34, 56, none)prints#fff0andhsla(120, 50%, 50%, none)prints#40bf4000. Chrome rejects both: the comma syntax has nonone.lch()oroklch()whose origin hue is infinite printsnoneforh:lch(from lch(50% 10 calc(infinity * 1deg)) l c h)islch(50% 10 none). Chrome computeslch(50 10 0). The hue is normalized withrem_euclid(360)after it is read.lab()with a number lightness or a percentage a and b is not read (css: parse number and percentage channels in lab(), lch(), oklab(), oklch(), hsl() and hwb() #45084). Two rows pinlab(calc(NaN) 10 0)andlab(50% calc(NaN * 1%) 0)as written. When a reader for them lands, it must give 0 and those rows must change.Measurements (release builds, merge base d0831bc and this branch)
CssColor::parseto its return (gdbstepi, 5 runs, no spread):lab(50% 10 0)2754 to 2769,rgb(12 34 56)3055 to 3064,rgb(12, 34, 56)3256 to 3271,hsl(120 50% 50%)3473 to 3482,lab(50% none 0)2960 to 2966,rgb(1 2 3 / var(--x))+9. With a math function that is not NaN: +12 to +15.rgb(calc(NaN) 0 0)goes from 3 allocations to 2, because it is stored as an 8-bit color..text: 81,316,949 B in both (llvm-size -A). Symbols: +219 B net (nm -S), of which 115 B are css: fail a percentage calc that cannot be reduced instead of folding it to NaN #45970. The four readers andRelativeComponentParser::parse_calcgrow by 163 B. Theparse_triginstances shrink by 59 B.CSSNumberFns::parse,Percentage::parseandAngle::parse_internal: no changed instruction (objdump -d, modulo addresses)..cssfiles and the 9 non-color NaN rows ofcss.test.tsminify to the same 2,564,636 bytes on both builds.Tests. On main, 73 rows of
css.test.ts, 16 ofcolor.test.tsand 3 ofwpt/color-computed-rgb.test.tsfail. On #45970 alone: 50, 15 and 3. Before the merge of main, the debug build passed all oftest/js/bun/css,test/bundler/cssandtest/bundler/esbuild/css.test.ts, except three files that hit their test timeouts under the debug build on this machine and pass on the release build of this branch:css-fuzz.test.ts,nested-selector-expansion.test.tsand, in one run of three,selector-list-error-recovery.test.ts. With main ea6a2c7 merged, the debug build passescss.test.ts,color.test.tsandwpt/color-computed-rgb.test.ts.Other open PRs. #45362 has the same
censor_nanfor the relative arm and can drop it. #45084 adds two literal arms that need the wrap. #45442 movesPercentage::from_calcand must keep the error. The build error for a typed@propertywith a valid relative color (hsl(from blue h s calc(l + 20))) comes from #45970, the first commit here: #45362 reads the keyword as a number, and #45806 keeps a typed value as written. #45806 merges with this branch with no text conflict. On a local merge (debug build),color.test.tsandtest/bundler/esbuild/css.test.tspass.css.test.tspasses except one subprocess test of main, which hit its 5 s timeout in the full run and passes alone.