0.8.0 - 2026-07-06

Release Notes

Crate release v0.8.0; ships on npm as sasso@0.11.0 (wasm + native — same
core). Byte-identity, complete: all 20 projects in the real-world corpus
compile byte-identical to dart-sass 1.101
(bench/real-world/real_world.md, 2.9–51×
faster end-to-end). The corpus doubled this release (tabler, AdminLTE,
reveal.js, Font Awesome, video.js, forem, nextcloud server,
jekyll-theme-chirpy, grafana, wagtail) and every divergence it surfaced was
fixed against dart-sass semantics — each pinned by a parity test.

Fixed (@extend engine — dart's per-registration model)

• @each over a single value — null included — iterates once (dart
  Value.asList). Bootstrap's valid-radius(null) relies on it; previously
  a css-less border-radius map key ERRORED the whole compile (tabler).
• The application fold runs each registration exactly once — no fixpoint.
  Extend cycles resolve the way dart's do: _extensionsByExtender[target] is
  a LIVE list, so an extender that itself contains the target self-derives
  within its own registration. The old fixpoint chained one extender of an
  @extend through its sibling of the same rule, emitting selectors dart
  never produces.
• Original selectors are identity-tracked (dart _originals is a
  Set.identity()): an extension product value-equal to one of the rule's
  own selectors is coverage-trimmed in the original's favor, keeping the
  original's position and source line break (.btn-sm,\n.btn-group-sm > .btn;
  h1, .h1 heading runs). dart's bare fast path (a single-simple compound
  replaced wholesale returns the extender object) carries identity too,
  scope-gated per module store — dart#1297 keeps the in-store :is() rewrite
  alongside its source while the cross-module variant replaces it.
• Foreign extensions apply in dart's cross-module store-merge order
  (downstream stores merge transitively; sibling stores reverse-first-load;
  derived entries follow their trigger's absorption order) — bulma's %block
  extender interleaving.
• Identical (target, extender) registrations merge per module store, not
  globally, so each keeps its own store-merge rank (chirpy's
  #access-lastmod a:hover position and line break).
• One @extend hitting several compounds of the same complex uses dart's
  paths order (first component varies fastest) on the incremental path
  too (forem's .crayons-btn + .crayons-btn file-selector products).
• Pre-rule extensions apply one-shot per dart's addSelector timing, and
  the one-shot gate compares registration indices, not counts.
• A placeholder-only module whose rules were all dropped counts as empty,
  so its group-separator blank collapses (uswds placeholders/).

Fixed (module system & output fidelity)

• The pre-module comment engine matches dart on three fronts (uswds):
  registration deep-scans pending comments through invisible module-scope
  placeholders; re-emitted clones are fenced and never re-register onto new
  module keys; a css-less module built while the shared comment map is
  non-empty absorbs pending registrations (dart's transitivelyContainsCss
  includes preModuleComments.isNotEmpty).
• Re-emitted pre-module clones stay out of the loader's import-run sweep
  (nextcloud's SPDX header no longer jumps to the top of the document).
• CSS @import hoisting keeps the css flow's eval-time grouping — dart's
  blank lines come solely from group-end flags, never source gaps; only the
  seam the pulled import run vacated is re-derived (forem).
• meta.load-css copies re-acquire per-rule group separators — dart
  re-visits the combined css node-by-node (reveal.js print styles).
• A trailing invisible chain owns the enclosing group's end at any nesting
  depth, packing the next group tight (chirpy).
• @at-root separators follow dart's _styleRule == null group-end gate
  — rules flattened out of a wrapper rule pack tight (wagtail's sidebar).
• Selector line-break parity with dart (pseudo-arg newlines,
  parent-resolution flags), loud comment re-indentation per dart's
  _loudComment, invisible-last-child groups pack the next group tight,
  and an empty module scope no longer anchors a group separator
  (bootstrap, quasar, mastodon, govuk-frontend byte-identity).

Added

• bench/real-world/: the vetted corpus doubled to 20 projects — every
  one compiled standalone with both engines and byte-compared on every run
  (node bench/real-world/run.mjs check is the regression gate).

Install sasso 0.8.0

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/momiji-rs/sasso/releases/download/v0.8.0/sasso-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://github.com/momiji-rs/sasso/releases/download/v0.8.0/sasso-installer.ps1 | iex"

Download sasso 0.8.0

File	Platform	Checksum
sasso-aarch64-apple-darwin.tar.xz	Apple Silicon macOS	checksum
sasso-x86_64-apple-darwin.tar.xz	Intel macOS	checksum
sasso-x86_64-pc-windows-msvc.zip	x64 Windows	checksum
sasso-aarch64-unknown-linux-gnu.tar.xz	ARM64 Linux	checksum
sasso-x86_64-unknown-linux-gnu.tar.xz	x64 Linux	checksum
sasso-aarch64-unknown-linux-musl.tar.xz	ARM64 MUSL Linux	checksum
sasso-x86_64-unknown-linux-musl.tar.xz	x64 MUSL Linux	checksum