errors: display original symbol name

If symbol names array has been populated in source map, include original symbol name in error message. Fixes #35325
nodejs · Nov 26, 2020 · 56d7975 · 56d7975
1 parent 6eec858
commit 56d7975
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Showing 4 changed files with 28 additions and 16 deletions.
diff --git a/doc/api/module.md b/doc/api/module.md
@@ -195,6 +195,7 @@ consists of the following keys:
 * originalSource: {string}
 * originalLine: {number}
 * originalColumn: {number}
+* name: {string}
 
 [CommonJS]: modules.md
 [ES Modules]: esm.md

diff --git a/lib/internal/source_map/prepare_stack_trace.js b/lib/internal/source_map/prepare_stack_trace.js
@@ -64,14 +64,14 @@ const prepareStackTrace = (globalThis, error, trace) => {
         const {
           originalLine,
           originalColumn,
-          originalSource
+          originalSource,
+          name
         } = sm.findEntry(t.getLineNumber() - 1, t.getColumnNumber() - 1);
         if (originalSource && originalLine !== undefined &&
             originalColumn !== undefined) {
           if (i === 0) {
             firstLine = originalLine + 1;
             firstColumn = originalColumn + 1;
-
             // Show error in original source context to help user pinpoint it:
             errorSource = getErrorSource(
               sm.payload,
@@ -81,11 +81,12 @@ const prepareStackTrace = (globalThis, error, trace) => {
             );
           }
           // Show both original and transpiled stack trace information:
+          const prefix = name ? `\n        -> at ${name}` : '\n        ->';
           const originalSourceNoScheme =
             StringPrototypeStartsWith(originalSource, 'file://') ?
               fileURLToPath(originalSource) : originalSource;
-          str += `\n        -> ${originalSourceNoScheme}:${originalLine + 1}:` +
-            `${originalColumn + 1}`;
+          str += `${prefix} (${originalSourceNoScheme}:${originalLine + 1}:` +
+            `${originalColumn + 1})`;
         }
       }
     } catch (err) {

diff --git a/lib/internal/source_map/source_map.js b/lib/internal/source_map/source_map.js
@@ -203,7 +203,8 @@ class SourceMap {
       generatedColumn: entry[1],
       originalSource: entry[2],
       originalLine: entry[3],
-      originalColumn: entry[4]
+      originalColumn: entry[4],
+      name: entry[5]
     };
   }
 
@@ -214,6 +215,7 @@ class SourceMap {
     let sourceIndex = 0;
     let sourceLineNumber = 0;
     let sourceColumnNumber = 0;
+    let nameIndex = 0;
 
     const sources = [];
     const originalToCanonicalURLMap = {};
@@ -229,6 +231,7 @@ class SourceMap {
 
     const stringCharIterator = new StringCharIterator(map.mappings);
     let sourceURL = sources[sourceIndex];
+    let name = map.names?.[nameIndex];
 
     while (true) {
       if (stringCharIterator.peek() === ',')
@@ -256,12 +259,13 @@ class SourceMap {
       }
       sourceLineNumber += decodeVLQ(stringCharIterator);
       sourceColumnNumber += decodeVLQ(stringCharIterator);
-      if (!isSeparator(stringCharIterator.peek()))
-        // Unused index into the names list.
-        decodeVLQ(stringCharIterator);
+      if (!isSeparator(stringCharIterator.peek())) {
+        nameIndex += decodeVLQ(stringCharIterator);
+        name = map.names?.[nameIndex];
+      }
 
       this.#mappings.push([lineNumber, columnNumber, sourceURL,
-                           sourceLineNumber, sourceColumnNumber]);
+                           sourceLineNumber, sourceColumnNumber, name]);
     }
   };
 }

diff --git a/test/parallel/test-source-map-enable.js b/test/parallel/test-source-map-enable.js
@@ -170,12 +170,15 @@ function nextdir() {
     '--enable-source-maps',
     require.resolve('../fixtures/source-map/uglify-throw.js')
   ]);
-  assert.ok(
-    output.stderr.toString().match(/->.*uglify-throw-original\.js:5:9/)
+  assert.match(
+    output.stderr.toString(),
+    /->.*uglify-throw-original\.js:5:9/
   );
-  assert.ok(
-    output.stderr.toString().match(/->.*uglify-throw-original\.js:9:3/)
+  assert.match(
+    output.stderr.toString(),
+    /->.*uglify-throw-original\.js:9:3/
   );
+  assert.match(output.stderr.toString(), /at Hello/);
 }
 
 // Applies source-maps generated by tsc to stack trace.
@@ -276,11 +279,14 @@ function nextdir() {
     require.resolve('../fixtures/source-map/webpack.js')
   ]);
   // Error in original context of source content:
-  assert.ok(
-    output.stderr.toString().match(/throw new Error\('oh no!'\)\r?\n.*\^/)
+  assert.match(
+    output.stderr.toString(),
+    /throw new Error\('oh no!'\)\r?\n.*\^/
   );
   // Rewritten stack trace:
-  assert.ok(output.stderr.toString().includes('webpack:///webpack.js:14:9'));
+  assert.match(output.stderr.toString(), /webpack:\/\/\/webpack\.js:14:9/);
+  assert.match(output.stderr.toString(), /at functionD/);
+  assert.match(output.stderr.toString(), /at functionC/);
 }
 
 // Stores and applies source map associated with file that throws while