fix: clean up webpack eval wrapper in stack traces

Author: feedthejim

packages/next/next-dev-server.webpack-config.js

@@ -194,6 +194,8 @@ module.exports = ({ dev }) => {
       path: path.join(__dirname, 'dist/compiled/dev-server'),
       filename: '[name].js',
       libraryTarget: 'commonjs2',
+      // Use absolute paths in source maps so error formatting can compute correct relative paths
+      devtoolModuleFilenameTemplate: '[absolute-resource-path]',
     },
     devtool: 'source-map',
     optimization: {

packages/next/src/server/dev/node-stack-frames.ts

@@ -1,5 +1,7 @@
 import { parse } from 'next/dist/compiled/stacktrace-parser'
 import type { StackFrame } from 'next/dist/compiled/stacktrace-parser'
+import path from 'path'
+import url from 'url'
 import {
   decorateServerError,
   type ErrorSourceType,
@@ -29,6 +31,25 @@ function getFilesystemFrame(frame: StackFrame): StackFrame {
   return f
 }
 
+/**
+ * Convert a file path to a path relative to the current working directory.
+ */
+function toRelativePath(filePath: string): string {
+  if (filePath.startsWith('file://')) {
+    try {
+      filePath = url.fileURLToPath(filePath)
+    } catch {
+      // Invalid file URL, use as-is
+    }
+  }
+
+  if (path.isAbsolute(filePath)) {
+    return path.relative(process.cwd(), filePath)
+  }
+
+  return filePath
+}
+
 export function getServerError(error: Error, type: ErrorSourceType): Error {
   if (error.name === 'TurbopackInternalError') {
     // If this is an internal Turbopack error we shouldn't show internal details
@@ -54,7 +75,8 @@ export function getServerError(error: Error, type: ErrorSourceType): Error {
       .map((f) => {
         let str = `    at ${f.methodName}`
         if (f.file) {
-          let loc = f.file
+          // Convert to relative path for cleaner output
+          let loc = toRelativePath(f.file)
           if (f.lineNumber) {
             loc += `:${f.lineNumber}`
             if (f.column) {

packages/next/src/server/lib/bytecode-cache.ts

@@ -1,35 +1,24 @@
 /**
- * Start Server Entry Point with Bytecode Caching
+ * Start Server Entry Point for Bundled Dev Server
  *
- * This is the entry point for the dev server that uses V8 bytecode caching
- * to speed up loading of the bundled dev server on subsequent startups.
+ * This module provides a unified entry point that can load either the bundled
+ * or unbundled dev server based on environment configuration.
  *
  * Environment variables:
- *   NEXT_DISABLE_BYTECODE_CACHE=1 - Disable bytecode caching
- *   NEXT_USE_UNBUNDLED_SERVER=1 - Use unbundled server instead
+ *   NEXT_USE_UNBUNDLED_SERVER=1 - Use unbundled server instead (for development)
  */
 
 import path from 'path'
-import { isBytecodeCacheEnabled, loadWithBytecodeCache } from './bytecode-cache'
 
 // Determine which server to load
 const useBundled = process.env.NEXT_USE_UNBUNDLED_SERVER !== '1'
-const useBytecodeCache = isBytecodeCacheEnabled() && useBundled
 
 const serverPath = useBundled
   ? path.join(__dirname, '../../compiled/dev-server/start-server.js')
   : path.join(__dirname, './start-server.js')
 
 // Load the server module
-let serverModule: typeof import('./start-server')
-
-if (useBytecodeCache) {
-  // Use bytecode caching for faster subsequent loads
-  serverModule = loadWithBytecodeCache(serverPath)
-} else {
-  // Regular require
-  serverModule = require(serverPath)
-}
+const serverModule: typeof import('./start-server') = require(serverPath)
 
 // Re-export everything from the server module
 export const { startServer, getRequestHandlers } = serverModule