@kdy1 has landed a fix for sourcemap locations in Turbopack with Windows. Could you give next@canary a try? Want to make sure it's now fully covered.

@timneutkens works great on my end. Client-side debugging behaved as expected. Server-side wasn’t mapped correctly though, so I had to manually add the mapping to my Node attach config to get it working:

{
  "name": "Next.js: Attach Debugger to Server",
  "request": "attach",
  "port": 9230,
  "type": "node",
  "sourceMapPathOverrides": {
    "turbopack:///[project]/*": "${workspaceFolder}/*"
  }
}

After that, server-side debugging worked fine too.
Thanks @kdy1!

@Andre9979 was that on next@canary or an earlier version? Would be helpful to have a reproduction of the case where it doesn't map automatically so we can look into it.

@timneutkens Thanks for following up! I initially tested this on the version where the sourcemap fix was landed ([email protected]), but the issue with server-side code not mapping automatically still persists in [email protected] (the latest canary at the time of writing).

Environment:

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 11 Pro
  Available memory (MB): 65299
  Available CPU cores: 20
Binaries:
  Node: 23.9.0
  npm: 10.9.2
  Yarn: N/A
  pnpm: 10.5.2
Relevant Packages:
  next: 15.4.0-canary.27 // Latest available version is detected (15.4.0-canary.27).
  eslint-config-next: 15.3.1
  react: 19.1.0
  react-dom: 19.1.0
  typescript: 5.8.3
Next.js Config:
  output: N/A

Reproduction steps:

1. Use [email protected] or [email protected]
2. Add the following to .vscode/launch.json:

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Next.js: Attach Debugger to Server",
      "request": "attach",
      "port": 9230,
      "type": "node"
    },
    {
      "name": "Next.js: Launch Server",
      "type": "node-terminal",
      "request": "launch",
      "command": "pnpm dev"
    }
  ],
  "compounds": [
    {
      "name": "Next.js: Launch Server Debugger",
      "configurations": [
        "Next.js: Launch Server",
        "Next.js: Attach Debugger to Server"
      ],
      "stopAll": true
    }
  ]
}

3. Add a breakpoint in server-side code (e.g., in middleware.ts).
4. Run the "Next.js: Launch Server Debugger" debug configuration in VS Code.
5. Open http://localhost:3000/ in a browser.
6. Observe: server-side breakpoints are not hit unless sourceMapPathOverrides is manually configured, as shown in my previous comment.

Current vs. Expected behavior

Expected: Server-side source maps are automatically resolved correctly, just like they are for client-side code.
Current: Server-side source maps are not correctly mapped by default and require manual configuration via sourceMapPathOverrides

@Andre9979 Do you know if it's the same in macos or linux, in case you tried? It would be good to know if it's a windows-specific bug.

@kdy1 I’ve only tested this on windows and don’t have access to macos or linux at the moment, so I can’t confirm whether it’s windows-specific.