From a967d8f39e2085fa1753a562d327eb9611359dab Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Sat, 17 Oct 2026 01:17:37 +0900
Subject: [PATCH] perf(browser): map only first frame for trace locations
 (#11613)

Co-authored-by: Hiroshi Ogawa <4232207+hi-ogawa@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
---
 .../browser-playwright/src/commands/trace.ts  |  2 +-
 packages/browser/src/node/commands/trace.ts   |  2 +-
 packages/utils/src/source-map.ts              | 95 +++++++++++--------
 packages/vitest/src/node/types/browser.ts     |  2 +-
 4 files changed, 59 insertions(+), 42 deletions(-)

diff --git a/packages/browser-playwright/src/commands/trace.ts b/packages/browser-playwright/src/commands/trace.ts
index 74e864da1..30ea95c83 100644
--- a/packages/browser-playwright/src/commands/trace.ts
+++ b/packages/browser-playwright/src/commands/trace.ts
@@ -133,7 +133,7 @@ function parseLocation(context: BrowserCommandContext, stack?: string): ParsedSt
   if (!stack) {
     return
   }
-  const parsedStacks = context.project.browser!.parseStacktrace(stack)
+  const parsedStacks = context.project.browser!.parseStacktrace(stack, { firstOnly: true })
   return parsedStacks[0]
 }
 
diff --git a/packages/browser/src/node/commands/trace.ts b/packages/browser/src/node/commands/trace.ts
index 63589a69b..686e57d4d 100644
--- a/packages/browser/src/node/commands/trace.ts
+++ b/packages/browser/src/node/commands/trace.ts
@@ -66,7 +66,7 @@ export const _recordBrowserTrace: BrowserCommand<
     if (!entry.stack || entry.location) {
       return entry
     }
-    const stacks = project.browser!.parseStacktrace(entry.stack)
+    const stacks = project.browser!.parseStacktrace(entry.stack, { firstOnly: true })
     if (stacks[0]) {
       entry.location = stacks[0]
     }
diff --git a/packages/utils/src/source-map.ts b/packages/utils/src/source-map.ts
index c49e8c878..a6892a2d0 100644
--- a/packages/utils/src/source-map.ts
+++ b/packages/utils/src/source-map.ts
@@ -9,6 +9,7 @@ export interface StackTraceParserOptions {
   getSourceMap?: (file: string) => unknown
   getUrlId?: (id: string) => string
   frameFilter?: (error: TestError, frame: ParsedStack) => boolean | void
+  firstOnly?: boolean
 }
 
 const CHROME_IE_STACK_REGEXP = /^\s*at .*(?:\S:\d+|\(native\))/m
@@ -248,51 +249,67 @@ export function parseStacktrace(
     stacks = stacks.slice(helperIndex + 1)
   }
 
-  return stacks
-    .map((stack) => {
-      if (options.getUrlId) {
-        stack.file = options.getUrlId(stack.file)
+  if (options.firstOnly) {
+    for (const stack of stacks) {
+      const mapped = mapStackFrame(stack, options, ignoreStackEntries)
+      if (mapped) {
+        return [mapped]
       }
+    }
+    return []
+  }
 
-      const map = options.getSourceMap?.(stack.file) as SourceMapLike | null | undefined
-      if (!map || typeof map !== 'object' || !map.version) {
-        return shouldFilter(ignoreStackEntries, stack.file) ? null : stack
-      }
+  return stacks
+    .map((stack) => mapStackFrame(stack, options, ignoreStackEntries))
+    .filter((s) => s != null)
+}
 
-      const traceMap = new DecodedMap(map, stack.file)
-      if (stack.line <= 0 || stack.column <= 0) {
-        return stack
-      }
-      const position = getOriginalPosition(traceMap, {
-        line: stack.line,
-        // stacktrace's column is 1-indexed, but sourcemap's one is 0-indexed
-        column: stack.column - 1,
-      })
-      if (!position) {
-        return stack
-      }
+function mapStackFrame(
+  stack: ParsedStack,
+  options: StackTraceParserOptions,
+  ignoreStackEntries: (string | RegExp)[],
+): ParsedStack | null {
+  if (options.getUrlId) {
+    stack.file = options.getUrlId(stack.file)
+  }
 
-      const { line, column, source, name } = position
-      let file = source || stack.file
-      if (/\/\w:\//.test(file)) {
-        file = file.slice(1)
-      }
+  const map = options.getSourceMap?.(stack.file) as SourceMapLike | null | undefined
+  if (!map || typeof map !== 'object' || !map.version) {
+    return shouldFilter(ignoreStackEntries, stack.file) ? null : stack
+  }
 
-      if (shouldFilter(ignoreStackEntries, file)) {
-        return null
-      }
+  const traceMap = new DecodedMap(map, stack.file)
+  if (stack.line <= 0 || stack.column <= 0) {
+    return stack
+  }
+  const position = getOriginalPosition(traceMap, {
+    line: stack.line,
+    // stacktrace's column is 1-indexed, but sourcemap's one is 0-indexed
+    column: stack.column - 1,
+  })
+  if (!position) {
+    return stack
+  }
 
-      if (line != null && column != null) {
-        return {
-          line,
-          column: column + 1,
-          file,
-          method: name || stack.method,
-        }
-      }
-      return stack
-    })
-    .filter((s) => s != null)
+  const { line, column, source, name } = position
+  let file = source || stack.file
+  if (/\/\w:\//.test(file)) {
+    file = file.slice(1)
+  }
+
+  if (shouldFilter(ignoreStackEntries, file)) {
+    return null
+  }
+
+  if (line != null && column != null) {
+    return {
+      line,
+      column: column + 1,
+      file,
+      method: name || stack.method,
+    }
+  }
+  return stack
 }
 
 function shouldFilter(ignoreStackEntries: (string | RegExp)[], file: string): boolean {
diff --git a/packages/vitest/src/node/types/browser.ts b/packages/vitest/src/node/types/browser.ts
index bcccf03ce..607618381 100644
--- a/packages/vitest/src/node/types/browser.ts
+++ b/packages/vitest/src/node/types/browser.ts
@@ -474,7 +474,7 @@ export interface ProjectBrowser {
   close: () => Promise<void>
   initBrowserProvider: (project: TestProject) => Promise<void>
   closeBrowserProvider: (options?: BrowserProviderCloseOptions) => Promise<void>
-  parseStacktrace: (stack: string) => ParsedStack[]
+  parseStacktrace: (stack: string, options?: StackTraceParserOptions) => ParsedStack[]
   parseErrorStacktrace: (error: TestError, options?: StackTraceParserOptions) => ParsedStack[]
   registerCommand: <K extends keyof BrowserCommands>(
     name: K,
-- 
2.54.0