Implement sass --embedded in pure JS mode

Author: ntkme

.github/workflows/ci.yml

@@ -117,17 +117,7 @@ jobs:
         working-directory: sass-spec
 
       - name: Compile
-        run: |
-          npm run compile
-          if [[ "$RUNNER_OS" == "Windows" ]]; then
-            # Avoid copying the entire Dart Sass build directory on Windows,
-            # since it may contain symlinks that cp will choke on.
-            mkdir -p dist/lib/src/vendor/dart-sass/
-            cp {`pwd`/,dist/}lib/src/vendor/dart-sass/sass.bat
-            cp {`pwd`/,dist/}lib/src/vendor/dart-sass/sass.snapshot
-          else
-            ln -s {`pwd`/,dist/}lib/src/vendor/dart-sass
-          fi
+        run: npm run compile
 
       - name: Run tests
         run: npm run js-api-spec -- --sassPackage .. --sassSassRepo ../language

bin/sass.ts

@@ -1,6 +1,7 @@
 #!/usr/bin/env node
 
 import * as child_process from 'child_process';
+import * as path from 'path';
 import {compilerCommand} from '../lib/src/compiler-path';
 
 // TODO npm/cmd-shim#152 and yarnpkg/berry#6422 - If and when the package
@@ -12,6 +13,10 @@ try {
     compilerCommand[0],
     [...compilerCommand.slice(1), ...process.argv.slice(2)],
     {
+      // Node blocks launching .bat and .cmd without a shell due to CVE-2024-27980
+      shell: ['.bat', '.cmd'].includes(
+        path.extname(compilerCommand[0]).toLowerCase(),
+      ),
       stdio: 'inherit',
       windowsHide: true,
     },

lib/src/compiler-path.ts

@@ -2,10 +2,8 @@
 // MIT-style license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
-import * as fs from 'fs';
 import * as p from 'path';
 import {getElfInterpreter} from './elf';
-import {isErrnoException} from './utils';
 
 /**
  * Detect if the given binary is linked with musl libc by checking if
@@ -23,57 +21,61 @@ function isLinuxMusl(path: string): boolean {
   }
 }
 
-/** The full command for the embedded compiler executable. */
-export const compilerCommand = (() => {
+/** The module name for the embedded compiler executable. */
+export const compilerModule = (() => {
   const platform =
     process.platform === 'linux' && isLinuxMusl(process.execPath)
       ? 'linux-musl'
       : (process.platform as string);
 
   const arch = process.arch;
 
-  // find for development
-  for (const path of ['vendor', '../../../lib/src/vendor']) {
-    const executable = p.resolve(
-      __dirname,
-      path,
-      `dart-sass/sass${platform === 'win32' ? '.bat' : ''}`,
-    );
-
-    if (fs.existsSync(executable)) return [executable];
-  }
+  return `sass-embedded-${platform}-${arch}`;
+})();
 
+/** The full command for the embedded compiler executable. */
+export const compilerCommand = (() => {
   try {
     return [
       require.resolve(
-        `sass-embedded-${platform}-${arch}/dart-sass/src/dart` +
-          (platform === 'win32' ? '.exe' : ''),
-      ),
-      require.resolve(
-        `sass-embedded-${platform}-${arch}/dart-sass/src/sass.snapshot`,
+        `${compilerModule}/dart-sass/src/dart` +
+          (process.platform === 'win32' ? '.exe' : ''),
       ),
+      require.resolve(`${compilerModule}/dart-sass/src/sass.snapshot`),
     ];
-  } catch (ignored) {
-    // ignored
+  } catch (e) {
+    if (e.code !== 'MODULE_NOT_FOUND') {
+      throw e;
+    }
   }
 
   try {
     return [
       require.resolve(
-        `sass-embedded-${platform}-${arch}/dart-sass/sass` +
-          (platform === 'win32' ? '.bat' : ''),
+        `${compilerModule}/dart-sass/sass` +
+          (process.platform === 'win32' ? '.bat' : ''),
       ),
     ];
-  } catch (e: unknown) {
-    if (!(isErrnoException(e) && e.code === 'MODULE_NOT_FOUND')) {
+  } catch (e) {
+    if (e.code !== 'MODULE_NOT_FOUND') {
+      throw e;
+    }
+  }
+
+  try {
+    return [
+      process.execPath,
+      p.join(p.dirname(require.resolve('sass')), 'sass.js'),
+    ];
+  } catch (e) {
+    if (e.code !== 'MODULE_NOT_FOUND') {
       throw e;
     }
   }
 
   throw new Error(
     "Embedded Dart Sass couldn't find the embedded compiler executable. " +
-      'Please make sure the optional dependency ' +
-      `sass-embedded-${platform}-${arch} is installed in ` +
-      'node_modules.',
+      `Please make sure the optional dependency ${compilerModule} or sass is ` +
+      'installed in node_modules.',
   );
 })();

tool/get-embedded-compiler.ts

@@ -2,9 +2,11 @@
 // MIT-style license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
+import {promises as fs} from 'fs';
 import * as p from 'path';
 import * as shell from 'shelljs';
 
+import {compilerModule} from '../lib/src/compiler-path';
 import * as utils from './utils';
 
 /**
@@ -14,7 +16,7 @@ import * as utils from './utils';
  * at `path`. By default, checks out the latest revision from GitHub.
  */
 export async function getEmbeddedCompiler(
-  outPath: string,
+  js?: boolean,
   options?: {ref: string} | {path: string},
 ): Promise<void> {
   const repo = 'dart-sass';
@@ -41,21 +43,43 @@ export async function getEmbeddedCompiler(
     await utils.link(languageInHost, languageInCompiler);
   }
 
-  buildDartSassEmbedded(source);
-  await utils.link(p.join(source, 'build'), p.join(outPath, repo));
+  buildDartSassEmbedded(source, js ?? false);
+
+  const jsModulePath = p.resolve('node_modules/sass');
+  const dartModulePath = p.resolve(p.join('node_modules', compilerModule));
+  if (js) {
+    await fs.rm(dartModulePath, {force: true, recursive: true});
+    await utils.link(p.join(source, 'build/npm'), jsModulePath);
+  } else {
+    await fs.rm(jsModulePath, {force: true, recursive: true});
+    await utils.link(p.join(source, 'build'), p.join(dartModulePath, repo));
+  }
 }
 
 // Builds the Embedded Dart Sass executable from the source at `repoPath`.
-function buildDartSassEmbedded(repoPath: string): void {
+function buildDartSassEmbedded(repoPath: string, js: boolean): void {
   console.log("Downloading Dart Sass's dependencies.");
   shell.exec('dart pub upgrade', {
     cwd: repoPath,
     silent: true,
   });
 
-  console.log('Building the Dart Sass executable.');
-  shell.exec('dart run grinder protobuf pkg-standalone-dev', {
-    cwd: repoPath,
-    env: {...process.env, UPDATE_SASS_PROTOCOL: 'false'},
-  });
+  if (js) {
+    shell.exec('npm install', {
+      cwd: repoPath,
+      silent: true,
+    });
+
+    console.log('Building the Dart Sass npm package.');
+    shell.exec('dart run grinder protobuf pkg-npm-dev', {
+      cwd: repoPath,
+      env: {...process.env, UPDATE_SASS_PROTOCOL: 'false'},
+    });
+  } else {
+    console.log('Building the Dart Sass executable.');
+    shell.exec('dart run grinder protobuf pkg-standalone-dev', {
+      cwd: repoPath,
+      env: {...process.env, UPDATE_SASS_PROTOCOL: 'false'},
+    });
+  }
 }

tool/init.ts

@@ -18,6 +18,10 @@ const argv = yargs(process.argv.slice(2))
     type: 'string',
     description: 'Build the Embedded Dart Sass binary from this Git ref.',
   })
+  .option('compiler-js', {
+    type: 'boolean',
+    description: 'Build the Embedded Dart Sass with dart2js.',
+  })
   .option('skip-compiler', {
     type: 'boolean',
     description: "Don't Embedded Dart Sass at all.",
@@ -55,15 +59,15 @@ void (async () => {
 
     if (!argv['skip-compiler']) {
       if (argv['compiler-ref']) {
-        await getEmbeddedCompiler(outPath, {
+        await getEmbeddedCompiler(argv['compiler-js'], {
           ref: argv['compiler-ref'],
         });
       } else if (argv['compiler-path']) {
-        await getEmbeddedCompiler(outPath, {
+        await getEmbeddedCompiler(argv['compiler-js'], {
           path: argv['compiler-path'],
         });
       } else {
-        await getEmbeddedCompiler(outPath);
+        await getEmbeddedCompiler(argv['compiler-js']);
       }
     }