lib: optimize prepareStackTrace on builtin frames

legendecas · aduh95 · commit e4b795ec4a18 · 2025-01-02T15:13:18.000+01:00
Only invalidates source map lookup cache when a new source map is found. This improves when user codes interleave with builtin functions, like `array.map`. PR-URL: #56299 Refs: #56296 Reviewed-By: Matteo Collina <matteo.collina@gmail.com> Reviewed-By: Xuguang Mei <meixuguang@gmail.com> Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Chemi Atlow <chemi@atlow.co.il> Reviewed-By: Pietro Marchini <pietro.marchini94@gmail.com>
diff --git a/benchmark/fixtures/simple-error-stack.js b/benchmark/fixtures/simple-error-stack.js
diff --git a/benchmark/fixtures/simple-error-stack.ts b/benchmark/fixtures/simple-error-stack.ts
@@ -5,11 +5,13 @@
 const lorem = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.';
 
 function simpleErrorStack() {
-  try {
-    (lorem as any).BANG();
-  } catch (e) {
-    return e.stack;
-  }
+  [1].map(() => {
+    try {
+      (lorem as any).BANG();
+    } catch (e) {
+      return e.stack;
+    }
+  })
 }
 
 export {
diff --git a/lib/internal/source_map/prepare_stack_trace.js b/lib/internal/source_map/prepare_stack_trace.js
@@ -53,9 +53,15 @@ function prepareStackTraceWithSourceMaps(error, trace) {
       const sm = fileName === lastFileName ?
         lastSourceMap :
         findSourceMap(fileName);
-      lastSourceMap = sm;
-      lastFileName = fileName;
+      // Only when a source map is found, cache it for the next iteration.
+      // This is a performance optimization to avoid interleaving with JS builtin function
+      // invalidating the cache.
+      // - at myFunc (file:///path/to/file.js:1:2)
+      // - at Array.map (<anonymous>)
+      // - at myFunc (file:///path/to/file.js:3:4)
       if (sm) {
+        lastSourceMap = sm;
+        lastFileName = fileName;
         return `${kStackLineAt}${serializeJSStackFrame(sm, callSite, trace[i + 1])}`;
       }
     } catch (err) {
diff --git a/lib/internal/source_map/source_map_cache.js b/lib/internal/source_map/source_map_cache.js
@@ -347,6 +347,11 @@ function findSourceMap(sourceURL) {
     return undefined;
   }
 
+  // No source maps for builtin modules.
+  if (sourceURL.startsWith('node:')) {
+    return undefined;
+  }
+
   SourceMap ??= require('internal/source_map/source_map').SourceMap;
   try {
     if (RegExpPrototypeExec(kLeadingProtocol, sourceURL) === null) {
