Make it possible to build npm with a linked language repo

This makes several changes:

* It renames the `UPDATE_SASS_PROTOCOL` environment variable used by
  the Grinder `protobuf` task to `UPDATE_SASS_SASS_REPO` to make it
  more generic and so usable by other tasks. The previous name still
  works but is considered deprecated.

* The `pkg-npm-*` grinder tasks now respects the
  `UPDATE_SASS_SASS_REPO` environment variable. This allows repos to
  ensure that the linked language repo's version of the TypeScript
  types are used when building the npm package.

* `UPDATE_SASS_SASS_REPO=false` is set for all the `pkg-npm-*` tasks
  run by this repo, so that they will use the linked language repo's
  version of the TypeScript types.

.github/util/initialize/action.yml

@@ -32,5 +32,5 @@ runs:
 
     - name: Generate Dart from protobuf
       run: dart run grinder protobuf
-      env: {UPDATE_SASS_PROTOCOL: false}
+      env: {UPDATE_SASS_SASS_REPO: false}
       shell: bash

.github/workflows/release.yml

@@ -70,6 +70,7 @@ jobs:
       - name: Deploy
         run: dart run grinder pkg-npm-deploy
         env:
+          UPDATE_SASS_SASS_REPO: false
           NPM_TOKEN: "${{ secrets.NPM_TOKEN }}"
 
   deploy_bazel:

.github/workflows/test.yml

@@ -113,6 +113,7 @@ jobs:
 
       - name: Build JS
         run: dart run grinder pkg-npm-dev
+        env: {UPDATE_SASS_SASS_REPO: false}
 
       - name: Check out Sass specification
         uses: sass/clone-linked-repo@v1
@@ -203,6 +204,7 @@ jobs:
 
       - name: Build JS
         run: dart run grinder pkg-npm-dev
+        env: {UPDATE_SASS_SASS_REPO: false}
 
       - name: Install built dependencies
         run: npm install
@@ -282,6 +284,7 @@ jobs:
           node-version: ${{ matrix.node-version }}
 
       - run: dart run grinder pkg-npm-dev
+        env: {UPDATE_SASS_SASS_REPO: false}
       - name: Run tests
         run: dart run test -t node -j 2
 
@@ -303,6 +306,7 @@ jobs:
         github-token: ${{ github.token }}
 
     - run: dart run grinder pkg-npm-dev
+      env: {UPDATE_SASS_SASS_REPO: false}
     - name: Run tests
       run: dart run test -p chrome -j 2
       env:

tool/grind.dart

@@ -251,10 +251,7 @@ dart run protoc_plugin "\$@"
     run('chmod', arguments: ['a+x', 'build/protoc-gen-dart']);
   }
 
-  if (Platform.environment['UPDATE_SASS_PROTOCOL'] != 'false') {
-    cloneOrCheckout("https://github.com/sass/sass.git", "main",
-        name: 'language');
-  }
+  _updateLanguageRepo();
 
   await runAsync("buf",
       arguments: ["generate"],
@@ -325,3 +322,19 @@ String _updateHomebrewLanguageRevision(String formula) {
       match.group(0)!.replaceFirst(match.group(1)!, languageRepoRevision) +
       formula.substring(match.end);
 }
+
+/// Clones the main branch of `github.com/sass/sass` and returns the path to the
+/// clone.
+///
+/// If the `UPDATE_SASS_SASS_REPO` environment variable is `false`, this instead
+/// assumes the repo that already exists at `build/language/sass`.
+/// `UPDATE_SASS_PROTOCOL` is also checked as a deprecated alias for
+/// `UPDATE_SASS_SASS_REPO`.
+String _updateLanguageRepo() =>
+    // UPDATE_SASS_PROTOCOL is considered deprecated, because it doesn't apply as
+    // generically to other tasks.
+    Platform.environment['UPDATE_SASS_SASS_REPO'] != 'false' &&
+            Platform.environment['UPDATE_SASS_PROTOCOL'] != 'false'
+        ? cloneOrCheckout("https://github.com/sass/sass.git", "main",
+            name: 'language')
+        : 'build/language/sass';