fix(core): fall back to AST for unusable sourcemaps

packages/core/src/inner-plugins/plugins/sourcemapTool.ts

@@ -213,6 +213,15 @@ export async function collectSourceMaps(
   }
 }
 
+function markAssetWithoutSourceMap(
+  assetsWithoutSourceMap: Set<string>,
+  assetName: unknown,
+) {
+  if (typeof assetName === 'string' && /\.(?:js|bundle|css)$/.test(assetName)) {
+    assetsWithoutSourceMap.add(assetName);
+  }
+}
+
 /**
  * Handles the afterEmit event for assets to collect source map information.
  * @param compilation - The current compilation object.
@@ -280,25 +289,29 @@ export async function handleAfterEmitAssets(
             });
           }
 
-          if (sourceMapAsset?.source) {
-            map = JSON.parse(sourceMapAsset.source.source().toString());
-            const outputPath = compilation.options.output?.path;
-            if (outputPath && typeof outputPath === 'string') {
-              sourceMapPath = resolve(outputPath, sourceMapAsset.name);
+          try {
+            const sourceMapContent = sourceMapAsset?.source?.source();
+            if (sourceMapContent) {
+              map = JSON.parse(sourceMapContent.toString());
             }
+          } catch (error) {
+            logger.debug(
+              `Error parsing source map asset ${sourceMapFile}:`,
+              error,
+            );
           }
-        } else {
-          // Mark asset as having no sourcemap for AST parsing fallback
-          // Only mark js/css files that don't have sourcemap
-          if (
-            assetName &&
-            typeof assetName === 'string' &&
-            (assetName.endsWith('.js') ||
-              assetName.endsWith('.bundle') ||
-              assetName.endsWith('.css'))
-          ) {
-            _this.assetsWithoutSourceMap.add(assetName);
+
+          if (!map) {
+            markAssetWithoutSourceMap(_this.assetsWithoutSourceMap, assetName);
+            continue;
           }
+
+          const outputPath = compilation.options.output?.path;
+          if (outputPath && typeof outputPath === 'string' && sourceMapAsset) {
+            sourceMapPath = resolve(outputPath, sourceMapAsset.name);
+          }
+        } else {
+          markAssetWithoutSourceMap(_this.assetsWithoutSourceMap, assetName);
           continue;
         }
       } else {
@@ -324,6 +337,7 @@ export async function handleAfterEmitAssets(
         );
       } catch (e) {
         logger.debug(e);
+        markAssetWithoutSourceMap(_this.assetsWithoutSourceMap, assetName);
       }
       _this.sourceMapSets.forEach((_value: string, key: string) => {
         if (!skipSources.has(key)) {

packages/core/tests/plugins/sourcemapTool.test.ts

@@ -321,7 +321,7 @@ describe('sourcemapTool', () => {
       expect(sourceMap).toBe('console.log("test");');
     });
 
-    it('should skip source map assets without a source', async () => {
+    it('should fall back to AST parsing when a related source map has no source', async () => {
       const plugin = createMockPluginInstance();
       const compilation = {
         compiler: { rspack: {} },
@@ -331,6 +331,18 @@ describe('sourcemapTool', () => {
           },
         },
         getAssets: () => [
+          {
+            name: 'main.js',
+            source: {
+              source: () => 'console.log("test");\n',
+              name: 'main.js',
+              sourceAndMap: () => ({
+                source: 'console.log("test");\n',
+                map: mockJsMap,
+              }),
+            },
+            info: {},
+          },
           {
             name: 'worker.abc123.js',
             source: {
@@ -355,7 +367,66 @@ describe('sourcemapTool', () => {
       } as any;
 
       await handleAfterEmitAssets(compilation, plugin);
-      expect(plugin.sourceMapSets.size).toBe(0);
+      expect(plugin.sourceMapSets.size).toBe(1);
+      expect(plugin.assetsWithoutSourceMap).toEqual(
+        new Set(['worker.abc123.js']),
+      );
+    });
+
+    it('should fall back to AST parsing when a related source map is invalid', async () => {
+      const plugin = createMockPluginInstance();
+      const compilation = {
+        compiler: { rspack: {} },
+        options: {
+          output: {
+            filename: '[name].[contenthash].js',
+          },
+        },
+        getAssets: () => [
+          {
+            name: 'main.js',
+            source: {
+              source: () => 'console.log("test");\n',
+              name: 'main.js',
+              sourceAndMap: () => ({
+                source: 'console.log("test");\n',
+                map: mockJsMap,
+              }),
+            },
+            info: {},
+          },
+          {
+            name: 'worker.abc123.js',
+            source: {
+              source: () => 'console.log("worker");\n',
+              name: 'worker.abc123.js',
+              sourceAndMap: () => ({
+                source: 'console.log("worker");\n',
+                map: null,
+              }),
+            },
+            info: {
+              related: {
+                sourceMap: 'worker.abc123.js.map',
+              },
+            },
+          },
+          {
+            name: 'worker.abc123.js.map',
+            source: {
+              source: () => '{}',
+              name: 'worker.abc123.js.map',
+            },
+            info: {},
+          },
+        ],
+      } as any;
+
+      await handleAfterEmitAssets(compilation, plugin);
+      expect(plugin.sourceMapSets.size).toBe(1);
+      expect(plugin.assetsWithoutSourceMap).toEqual(
+        new Set(['worker.abc123.js']),
+      );
     });
 
     it('should find source map by base name without hash when exact match fails', async () => {