Issue #3414173 by joelpittet, anybody, nicxvan: Add support for minified external CSS libraries

(cherry picked from commit 8986a105)

core/lib/Drupal/Core/Asset/CssCollectionOptimizerLazy.php

@@ -148,8 +148,15 @@ public function optimizeGroup(array $group): string {
         $data .= "/* @license " . $css_asset['license']['name'] . " " . $css_asset['license']['url'] . " */\n";
       }
       $current_license = $css_asset['license'];
+
+      // Append this file if already minified; otherwise optimize it.
+      if (isset($css_asset['minified']) && $css_asset['minified']) {
+        $data .= file_get_contents($css_asset['data']);
+      }
+      else {
         $data .= $this->optimizer->optimize($css_asset);
       }
+    }
     // Per the W3C specification at
     // https://www.w3.org/TR/REC-CSS2/cascade.html#at-import, @import rules must
     // precede any other style, so we move those to the top. The regular

core/tests/Drupal/Tests/Core/Asset/CssCollectionOptimizerLazyUnitTest.php

@@ -148,4 +148,40 @@ public function testCssLicenseAggregation(): void {
     self::assertStringEqualsFile(__DIR__ . '/css_test_files/css_license.css.optimized.aggregated.css', $aggregate);
   }
 
+  /**
+   * Test that external minified CSS assets do not trigger optimization.
+   *
+   * This ensures that fully external asset groups do not result in a
+   * CssOptimizer exception and are safely ignored.
+   */
+  public function testExternalMinifiedCssAssetOptimizationIsSkipped(): void {
+    $mock_grouper = $this->createMock(AssetCollectionGrouperInterface::class);
+    $mock_optimizer = $this->createMock(AssetOptimizerInterface::class);
+    $mock_optimizer->expects($this->never())->method('optimize');
+
+    $optimizer = new CssCollectionOptimizerLazy(
+      $mock_grouper,
+      $mock_optimizer,
+      $this->createMock(ThemeManagerInterface::class),
+      $this->createMock(LibraryDependencyResolverInterface::class),
+      new RequestStack(),
+      $this->createMock(FileSystemInterface::class),
+      $this->createMock(ConfigFactoryInterface::class),
+      $this->createMock(FileUrlGeneratorInterface::class),
+      $this->createMock(TimeInterface::class),
+      $this->createMock(LanguageManagerInterface::class)
+    );
+    $optimizer->optimizeGroup([
+      'items' => [
+        [
+          'type' => 'external',
+          'data' => __DIR__ . '/css_test_files/css_external.optimized.aggregated.css',
+          'license' => FALSE,
+          'preprocess' => TRUE,
+          'minified' => TRUE,
+        ],
+      ],
+    ]);
+  }
+
 }

core/tests/Drupal/Tests/Core/Asset/css_test_files/css_external.optimized.aggregated.css

+/* Placeholder external CSS file. */