"nuxt dev --inspect" tries to create multiple processes trying to listen on the same port

[konstantin-lukas]

When you run the dev server with the inspect flag, you will see the following in the console:

$ npm run debug

> debug
> nuxt dev --inspect

│                                                                                                                                                                                                                      10:52:55 PM
●  Nuxt 4.2.2 (with Nitro 2.13.1, Vite 7.3.1 and Vue 3.5.27)
                                                                                                                                                                                                                       10:52:55 PM
  ➜ Local:    http://localhost:3000/
  ➜ Network:  use --host to expose

  ➜ DevTools: press Shift + Alt + D in the browser (v3.1.1)                                                                                                                                                            10:52:55 PM

✔ Vite client built in 13ms                                                                                                                                                                                           10:52:55 PM
✔ Vite server built in 27ms                                                                                                                                                                                           10:52:55 PM
✔ Nuxt Nitro server built in 307ms                                                                                                                                                                              nitro 10:52:55 PM
ℹ Vite server warmed up in 0ms                                                                                                                                                                                        10:52:55 PM
ℹ Vite client warmed up in 1ms                                                                                                                                                                                        10:52:55 PM
Debugger listening on ws://127.0.0.1:9229/71842a71-8c5c-49a3-aabd-7ddab5b96971
For help, see: https://nodejs.org/en/docs/inspector
Starting inspector on 127.0.0.1:9229 failed: address already in use

Notice that at the end it's trying to start an inspector on the same port as the debugger. I'm not sure if this is 100% related but it would make sense: I'm trying to debug my backend code. So far, I have been unable to do so. I try to attach the debugger from my IDE (WebStorm) to 9229, I get a frontend debugger that shows me the browser console. This is not very helpful. So I was thinking, perhaps the other process that failed to start might be another debugging process but for the h3 server. I also added the nuxt.run.yml described in the docs but that seems unrelated to this issue.

To reproduce:

• Start a fresh Nuxt Project (I tried using the latest 4.2.2 but also 3.20.X)
• Add a new script to the package.json named "debug" with the value "nuxt dev --inspect"
• Run: npm run debug

[n0099]

lsof -sTCP:LISTEN -nPi :9229

shows only the highlighted process in tree with lower pid so started more early will win the port listening race, but I want to inspect the root process of tree.
A workaround for this is running node --inspect node_modules/.bin/nuxt dev that creates no subprocess instead of nuxt dev.