fix(heft-sass-plugin): wire ignoreDeprecationsInDependencies to Sass quietDeps

common/changes/@rushstack/heft-sass-plugin/fix-ignoreDeprecationsInDependencies_2026-06-19-18-35.json

@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "comment": "Fix `ignoreDeprecationsInDependencies` option being silently ignored; it is now correctly forwarded to the Sass compiler's `quietDeps` flag.",
+      "type": "patch",
+      "packageName": "@rushstack/heft-sass-plugin"
+    }
+  ],
+  "packageName": "@rushstack/heft-sass-plugin",
+  "email": "copilot@users.noreply.github.com"
+}

heft-plugins/heft-sass-plugin/src/SassPlugin.ts

@@ -27,6 +27,7 @@ export interface ISassConfigurationJson {
   exportAsDefault?: boolean;
   fileExtensions?: string[];
   nonModuleFileExtensions?: string[];
+  ignoreDeprecationsInDependencies?: boolean;
   silenceDeprecations?: string[];
   excludeFiles?: string[];
   doNotTrimOriginalFileExtension?: boolean;
@@ -98,6 +99,7 @@ export default class SassPlugin implements IHeftPlugin {
           exportAsDefault = true,
           fileExtensions,
           nonModuleFileExtensions,
+          ignoreDeprecationsInDependencies,
           silenceDeprecations,
           excludeFiles,
           doNotTrimOriginalFileExtension,
@@ -129,6 +131,7 @@ export default class SassPlugin implements IHeftPlugin {
             };
           }),
           silenceDeprecations,
+          ignoreDeprecationsInDependencies,
           doNotTrimOriginalFileExtension,
           preserveIcssExports,
           sourceMap,

heft-plugins/heft-sass-plugin/src/SassProcessor.ts

@@ -211,7 +211,7 @@ export class SassProcessor {
   private _configFilePath: string | undefined;
 
   public constructor(options: ISassProcessorOptions) {
-    const { silenceDeprecations, excludeFiles } = options;
+    const { silenceDeprecations, excludeFiles, ignoreDeprecationsInDependencies } = options;
 
     const { isFileModule, allFileExtensions } = buildExtensionClassifier(options);
 
@@ -261,6 +261,7 @@ export class SassProcessor {
     this._resolutions = new Map();
     this._options = options;
     this._realpathSync = new RealNodeModulePathResolver().realNodeModulePath;
+    const { terminal } = options.logger;
     this._scssOptions = {
       style: 'expanded', // leave minification to clean-css
       importers: [
@@ -270,7 +271,17 @@ export class SassProcessor {
           load: loadAsync
         }
       ],
+      logger: {
+        warn: (message, { deprecation }) => {
+          if (deprecation) {
+            terminal.writeWarningLine(`Deprecation Warning: ${message}`);
+          } else {
+            terminal.writeWarningLine(`Warning: ${message}`);
+          }
+        }
+      },
       silenceDeprecations: deprecationsToSilence,
+      quietDeps: ignoreDeprecationsInDependencies,
       ...(options.sourceMap && { sourceMap: true, sourceMapIncludeSources: true })
     };
   }

heft-plugins/heft-sass-plugin/src/test/SassProcessor.test.ts

@@ -29,6 +29,7 @@ type ICreateProcessorOptions = Partial<
     | 'dtsOutputFolders'
     | 'exportAsDefault'
     | 'fileExtensions'
+    | 'ignoreDeprecationsInDependencies'
     | 'nonModuleFileExtensions'
     | 'postProcessCssAsync'
     | 'preserveIcssExports'
@@ -596,6 +597,24 @@ describe(SassProcessor.name, () => {
     });
   });
 
+  describe('ignoreDeprecationsInDependencies option', () => {
+    it('emits deprecation warnings from a dependency partial by default', async () => {
+      const { processor, logger } = createProcessor(terminalProvider);
+      await compileFixtureAsync(processor, 'use-partial-with-color-deprecation.module.scss');
+      expect(logger.errors).toHaveLength(0);
+      expect(terminalProvider.getWarningOutput()).toContain('Deprecation Warning:');
+    });
+
+    it('suppresses deprecation warnings from a dependency partial when ignoreDeprecationsInDependencies is true', async () => {
+      const { processor, logger } = createProcessor(terminalProvider, {
+        ignoreDeprecationsInDependencies: true
+      });
+      await compileFixtureAsync(processor, 'use-partial-with-color-deprecation.module.scss');
+      expect(logger.errors).toHaveLength(0);
+      expect(terminalProvider.getWarningOutput()).not.toContain('Deprecation Warning:');
+    });
+  });
+
   describe('non-module (global) files', () => {
     it('emits plain compiled CSS for a .global.scss file', async () => {
       const { processor } = createProcessor(terminalProvider, {

heft-plugins/heft-sass-plugin/src/test/fixtures/_partial-with-color-deprecation.scss

@@ -0,0 +1,5 @@
+// This partial intentionally uses darken(), a deprecated Sass global color function.
+// It exists only to test the ignoreDeprecationsInDependencies option.
+.dep-style {
+  color: darken(#0078d4, 10%);
+}

heft-plugins/heft-sass-plugin/src/test/fixtures/use-partial-with-color-deprecation.module.scss

@@ -0,0 +1,7 @@
+// This file @use's a partial that contains a deprecated Sass function.
+// It exists only to test the ignoreDeprecationsInDependencies option.
+@use 'partial-with-color-deprecation';
+
+.container {
+  color: red;
+}