Sample

Run lightningcss on Alpine, where the native addon really does come in per-libc builds

sha256:de0de7aea8370a5ddbb611169fcb1bf333cb27e4a8318c0be8d18fb57c45682e

Case

Goal

Run lightningcss on Alpine, where the native addon really does come in per-libc builds HOW

Packages

lightningcss 1.33.0 lightningcss-linux-x64-musl 1.33.0 lightningcss-linux-x64-gnu 1.33.0 detect-libc 2.1.2

Environment

node 22

Created

2026-08-14T13:01:58Z

Contract

• minify CSS with lightningcss on a musl image with lifecycle scripts disabled, asserting the merged margin shorthand
• assert transform returns code as a Buffer that equals the expected string under == and in a template string but is never === it
• assert targets lower CSS nesting for Chrome 90 and leave the nested rule alone for Chrome 130
• assert targets are packed as major << 16, so a bare 130 means Chrome 0.0.130 and lowers everything
• assert @custom-media needs both drafts.customMedia and targets, and lowers to queries joined with or
• assert an undefined custom media reference throws SyntaxError with data.type CustomMediaNotDefined and a source location
• assert exactly one .node was dlopened and it is the musl platform package, read from the CJS module cache
• assert the image is musl, that the specifier the loader builds is lightningcss-linux-x64-musl, and that detect-libc is lightningcss's only runtime dependency
• assert from the installed loader's own source that it calls detect-libc familySync at require time, requires the platform package by name, and only then falls back to a .node in the package root
• assert both linux-x64 platform packages declare libc, musl and glibc respectively
• assert npm ci installed BOTH linux-x64 libc variants because the lockfile records os and cpu on every optional entry but never libc
• assert the image ships the npm 10 whose lockfile writer drops libc, since npm 12 records it and then installs only the musl package
• assert the unusable glibc binary is a full second copy of the 10 MB addon on disk
• assert from the ELF dynamic sections that the musl build needs libc.musl-x86_64.so.1 and the glibc build needs libc.so.6 and ld-linux-x86-64.so.2
• assert requiring the installed glibc binary fails with ERR_DLOPEN_FAILED naming the missing glibc loader
• assert a platform package that was never installed fails earlier, at resolution, with MODULE_NOT_FOUND
• assert the classic Cannot find module lightningcss.linux-x64-musl.node is MODULE_NOT_FOUND from the loader's local-build fallback, meaning the platform package is absent rather than wrong

Files

• csx.json
• package-lock.json
• package.json
• src/compile.mjs
• test/contract.mjs

Origin Seeder

anonymous

Verification receipts

• node 22 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · npm@1 · 2026-08-14 · ed25519:a2ec939a4c60e243
• · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · npm@1 · 2026-08-14 · ed25519:7da3f610facce8bf
• · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · npm@1 · 2026-08-14 · ed25519:7da3f610facce8bf
• · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · npm@1 · 2026-08-14 · ed25519:7da3f610facce8bf
• · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · npm@1 · 2026-08-14 · ed25519:7da3f610facce8bf