chore: s/lightningcss-wasm/postcss

.changeset/postcss-fallback.md

@@ -0,0 +1,5 @@
+---
+'@doc-kit/generator-react': patch
+---
+
+Fall back to PostCSS, rather than Lightning CSS's wasm build, on platforms without native Lightning CSS bindings

packages/react/package.json

@@ -45,7 +45,6 @@
     "hast-util-to-html": "^9.0.5",
     "hast-util-to-string": "^3.0.1",
     "hastscript": "^9.0.1",
-    "lightningcss-wasm": "^1.33.0",
     "mdast-util-slice-markdown": "^2.0.1",
     "preact": "^10.29.7",
     "preact-render-to-string": "^6.7.0",

packages/react/src/html/README.md

@@ -301,10 +301,15 @@ export default {
 
 The generator owns the fields required to coordinate its builds: config-file
 loading, app type and base, virtual inputs, Preact compatibility aliases and
-automatic JSX runtime, the Lightning CSS transformer, output/write mode, SSR
-format and output, and SSR dependency bundling. Values supplied for those
-fields are replaced after configuration is merged. User plugins are registered
-after the generator's virtual-module plugin; other Vite options are preserved.
+automatic JSX runtime, the CSS transformer, output/write mode, SSR format and
+output, and SSR dependency bundling. Values supplied for those fields are
+replaced after configuration is merged. User plugins are registered after the
+generator's virtual-module plugin; other Vite options are preserved.
+
+CSS is transformed and minified by Lightning CSS. On platforms without its
+native bindings, such as ppc64 and s390x, Vite's PostCSS pipeline transforms
+the CSS instead and the output is not minified; `css.lightningcss` options have
+no effect there.
 
 Vite builds the client entry as a module, not the pages as HTML entries, so
 plugins see and can transform every module of the client and server builds but

packages/react/src/html/bundlers/__tests__/vite.test.mjs

@@ -108,6 +108,21 @@ describe('Vite configuration', () => {
     );
   });
 
+  it('transforms CSS with Lightning CSS where its bindings are native', () => {
+    const config = createViteConfig({
+      sources: new Map(),
+      input: {},
+      server: false,
+      outDir: output,
+      config: getConfig('html'),
+      vite: { css: { lightningcss: { targets: {} } } },
+    });
+
+    assert.strictEqual(config.css.transformer, 'lightningcss');
+    assert.deepStrictEqual(config.css.lightningcss, { targets: {} });
+    assert.strictEqual(config.build.cssMinify, undefined);
+  });
+
   it('keeps the server library self-contained', () => {
     const vite = {
       ssr: {

packages/react/src/html/bundlers/vite.mjs

@@ -2,7 +2,6 @@ import { readFile, rm, rmdir } from 'node:fs/promises';
 import { dirname, join, posix, resolve } from 'node:path';
 import { fileURLToPath, pathToFileURL } from 'node:url';
 
-import './wasm-fallback.mjs';
 import {
   build as viteBuild,
   defaultClientConditions,
@@ -138,6 +137,9 @@ export const createViteConfig = ({
   const root = resolve(vite.root ?? process.cwd());
   const conditions = server ? defaultServerConditions : defaultClientConditions;
 
+  // Lightning CSS publishes no native bindings for these platforms
+  const lightningcss = process.arch !== 'ppc64' && process.arch !== 's390x';
+
   return {
     ...vite,
 
@@ -194,15 +196,21 @@ export const createViteConfig = ({
     },
 
     // CSS imports, modules, URLs, splitting, and minification are all Vite
-    // responsibilities. Native Lightning CSS options remain configurable.
+    // responsibilities. Lightning CSS transforms the CSS, with its options
+    // configurable, on platforms that have its native bindings; elsewhere
+    // Vite's PostCSS pipeline transforms it instead.
     css: {
       ...vite.css,
-      transformer: 'lightningcss',
+      transformer: lightningcss ? 'lightningcss' : 'postcss',
     },
 
     build: {
       ...vite.build,
 
+      // Vite's only CSS minifier is Lightning CSS itself, so without its
+      // bindings the CSS is left as PostCSS produced it.
+      ...(lightningcss ? {} : { cssMinify: false }),
+
       // Both builds are complete Vite outputs. The server library goes to a
       // private directory; the client writes into the final site.
       outDir,