fix NODE_OPTIONS=inspect

[ztanner]

Passing NODE_OPTIONS='--inspect' was failing because a sub-process was getting created (getRegistry()) which would trigger a "address already in use" error when the process inherited the same debugger port from the parent process.

I had to disable this test in #59508 because it wasn't passing, CI was just skipping it. This PR fixes the behavior and re-enables the test.

Fixes #55862

Closes NEXT-1854

[ztanner]

Current dependencies on/for this PR:

• canary
  • PR fix NODE_OPTIONS=inspect #59530 👈

This stack of pull requests is managed by Graphite.

[ijjk]

Stats from current PR

Default Build

General Overall increase ⚠️

	vercel/next.js canary	vercel/next.js 12-12-fix_NODE_OPTIONS_inspect	Change
buildDuration	10.7s	10.9s	⚠️ +235ms
buildDurationCached	5.9s	6.1s	⚠️ +200ms
nodeModulesSize	200 MB	200 MB	⚠️ +1.38 kB
nextStartRea..uration (ms)	423ms	421ms	N/A

Client Bundles (main, webpack)

	vercel/next.js canary	vercel/next.js 12-12-fix_NODE_OPTIONS_inspect	Change
170-HASH.js gzip	26.7 kB	26.7 kB	N/A
199.HASH.js gzip	181 B	185 B	N/A
3f784ff6-HASH.js gzip	53.3 kB	53.3 kB	✓
framework-HASH.js gzip	45.2 kB	45.2 kB	✓
main-app-HASH.js gzip	240 B	241 B	N/A
main-HASH.js gzip	31.7 kB	31.6 kB	N/A
webpack-HASH.js gzip	1.7 kB	1.7 kB	N/A
Overall change	98.5 kB	98.5 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js 12-12-fix_NODE_OPTIONS_inspect	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	vercel/next.js 12-12-fix_NODE_OPTIONS_inspect	Change
_app-HASH.js gzip	195 B	194 B	N/A
_error-HASH.js gzip	183 B	182 B	N/A
amp-HASH.js gzip	501 B	501 B	✓
css-HASH.js gzip	321 B	321 B	✓
dynamic-HASH.js gzip	2.5 kB	2.5 kB	N/A
edge-ssr-HASH.js gzip	255 B	255 B	✓
head-HASH.js gzip	349 B	350 B	N/A
hooks-HASH.js gzip	368 B	369 B	N/A
image-HASH.js gzip	4.27 kB	4.27 kB	N/A
index-HASH.js gzip	255 B	256 B	N/A
link-HASH.js gzip	2.61 kB	2.6 kB	N/A
routerDirect..HASH.js gzip	311 B	309 B	N/A
script-HASH.js gzip	384 B	384 B	✓
withRouter-HASH.js gzip	307 B	306 B	N/A
1afbb74e6ecf..834.css gzip	106 B	106 B	✓
Overall change	1.57 kB	1.57 kB	✓

Client Build Manifests

	vercel/next.js canary	vercel/next.js 12-12-fix_NODE_OPTIONS_inspect	Change
_buildManifest.js gzip	484 B	482 B	N/A
Overall change	0 B	0 B	✓

Rendered Page Sizes

	vercel/next.js canary	vercel/next.js 12-12-fix_NODE_OPTIONS_inspect	Change
index.html gzip	530 B	527 B	N/A
link.html gzip	542 B	540 B	N/A
withRouter.html gzip	524 B	524 B	✓
Overall change	524 B	524 B	✓

Edge SSR bundle Size

	vercel/next.js canary	vercel/next.js 12-12-fix_NODE_OPTIONS_inspect	Change
edge-ssr.js gzip	93.7 kB	93.7 kB	N/A
page.js gzip	146 kB	146 kB	N/A
Overall change	0 B	0 B	✓

Middleware size

	vercel/next.js canary	vercel/next.js 12-12-fix_NODE_OPTIONS_inspect	Change
middleware-b..fest.js gzip	625 B	622 B	N/A
middleware-r..fest.js gzip	151 B	151 B	✓
middleware.js gzip	37.4 kB	37.4 kB	N/A
edge-runtime..pack.js gzip	1.92 kB	1.92 kB	✓
Overall change	2.07 kB	2.07 kB	✓

Next Runtimes

	vercel/next.js canary	vercel/next.js 12-12-fix_NODE_OPTIONS_inspect	Change
app-page-exp...dev.js gzip	168 kB	168 kB	✓
app-page-exp..prod.js gzip	93.9 kB	93.9 kB	✓
app-page-tur..prod.js gzip	94.7 kB	94.7 kB	✓
app-page-tur..prod.js gzip	89.2 kB	89.2 kB	✓
app-page.run...dev.js gzip	138 kB	138 kB	✓
app-page.run..prod.js gzip	88.5 kB	88.5 kB	✓
app-route-ex...dev.js gzip	23.9 kB	23.9 kB	✓
app-route-ex..prod.js gzip	16.6 kB	16.6 kB	✓
app-route-tu..prod.js gzip	16.6 kB	16.6 kB	✓
app-route-tu..prod.js gzip	16.2 kB	16.2 kB	✓
app-route.ru...dev.js gzip	23.4 kB	23.4 kB	✓
app-route.ru..prod.js gzip	16.2 kB	16.2 kB	✓
pages-api-tu..prod.js gzip	9.37 kB	9.37 kB	✓
pages-api.ru...dev.js gzip	9.64 kB	9.64 kB	✓
pages-api.ru..prod.js gzip	9.37 kB	9.37 kB	✓
pages-turbo...prod.js gzip	21.9 kB	21.9 kB	✓
pages.runtim...dev.js gzip	22.5 kB	22.5 kB	✓
pages.runtim..prod.js gzip	21.9 kB	21.9 kB	✓
server.runti..prod.js gzip	49.4 kB	49.4 kB	✓
Overall change	929 kB	929 kB	✓

Commit: 621fc98

[huozhi]

Nice finding

[bivainis]

After installing 14.0.5-canary.19, I can confirm this error is now gone.

However, to make Chrome pause on debugger statements, I had to add the missing target to the list:

1. open chrome://inspect
2. click on "Configure..." next to "Discover network targets"
3. add localhost:9230

package.json

{
  "scripts": {
    "dev:inspect": "NODE_OPTIONS='--inspect' next dev"
  }
{

Run the app: npm run dev:inspect

Open chrome://inspect and click on "Open dedicated DevTools for Node"

The DevTools that open should show something similar:

the --inspect option was detected, the Next.js router server should be inspected at port 9230.
log.ts:39   �[1m�[38;2;173;127;168m ▲ Next.js 14.0.5-canary.19�[39m�[22m
log.ts:39    - Local:        http://localhost:3000
log.ts:39    - Environments: .env.local
log.ts:32 
log.ts:34  ✓ Ready in 2.2s

If it doesn't, try to inspect another target in the list of remote targets in chrome://inspect

[AndreMiras]

I actually got it working with Next 14.0.4 after adding localhost:9230 in the target
Edit: but yes I do get the address already in use error in 14.0.4, but it wouldn't prevent the debugging as long as I set the target to 9230