misc: fix injecting --inspect with NODE_OPTIONS (#57159)

This PR fixes the passing of the `--inspect` option when calling Next.js with it. It's still not great because you need to target the next file in node_modules directly but I'll add a `next --inspect` option in the future.

packages/next/src/cli/next-dev.ts

@@ -2,7 +2,14 @@
 
 import '../server/lib/cpu-profile'
 import type { StartServerOptions } from '../server/lib/start-server'
-import { RESTART_EXIT_CODE, getPort, printAndExit } from '../server/lib/utils'
+import {
+  RESTART_EXIT_CODE,
+  checkNodeDebugType,
+  getDebugPort,
+  getNodeOptionsWithoutInspect,
+  getPort,
+  printAndExit,
+} from '../server/lib/utils'
 import * as Log from '../build/output/log'
 import type { CliCommand } from '../lib/commands'
 import { getProjectDir } from '../lib/get-project-dir'
@@ -223,6 +230,15 @@ const nextDev: CliCommand = async (args) => {
       let resolved = false
       const defaultEnv = (initialEnv || process.env) as typeof process.env
 
+      let NODE_OPTIONS = getNodeOptionsWithoutInspect()
+      let nodeDebugType = checkNodeDebugType()
+
+      if (nodeDebugType) {
+        NODE_OPTIONS = `${NODE_OPTIONS} --${nodeDebugType}=${
+          getDebugPort() + 1
+        }`
+      }
+
       child = fork(startServerPath, {
         stdio: 'inherit',
         env: {
@@ -232,6 +248,7 @@ const nextDev: CliCommand = async (args) => {
           NODE_EXTRA_CA_CERTS: options.selfSignedCertificate
             ? options.selfSignedCertificate.rootCA
             : defaultEnv.NODE_EXTRA_CA_CERTS,
+          NODE_OPTIONS,
         },
       })
 

packages/next/src/server/lib/router-server.ts

@@ -63,8 +63,6 @@ export async function initialize(opts: {
   experimentalTestProxy?: boolean
   experimentalHttpsServer?: boolean
 }): Promise<[WorkerRequestHandler, WorkerUpgradeHandler]> {
-  process.title = 'next-router-worker'
-
   if (!process.env.NODE_ENV) {
     // @ts-ignore not readonly
     process.env.NODE_ENV = opts.dev ? 'development' : 'production'

packages/next/src/server/lib/start-server.ts

@@ -15,10 +15,9 @@ import https from 'https'
 import Watchpack from 'watchpack'
 import * as Log from '../../build/output/log'
 import setupDebug from 'next/dist/compiled/debug'
-import { RESTART_EXIT_CODE, getDebugPort } from './utils'
+import { RESTART_EXIT_CODE, checkNodeDebugType, getDebugPort } from './utils'
 import { formatHostname } from './format-hostname'
 import { initialize } from './router-server'
-import { checkIsNodeDebugging } from './is-node-debugging'
 import { CONFIG_FILES } from '../../shared/lib/constants'
 import { getStartServerInfo, logStartInfo } from './app-info-log'
 
@@ -86,6 +85,7 @@ export async function startServer({
   isExperimentalTestProxy,
   selfSignedCertificate,
 }: StartServerOptions): Promise<void> {
+  process.title = 'next-server'
   let handlersReady = () => {}
   let handlersError = () => {}
 
@@ -183,7 +183,7 @@ export async function startServer({
     }
   })
 
-  const isNodeDebugging = checkIsNodeDebugging()
+  const nodeDebugType = checkNodeDebugType()
 
   await new Promise<void>((resolve) => {
     server.on('listening', async () => {
@@ -207,12 +207,10 @@ export async function startServer({
         selfSignedCertificate ? 'https' : 'http'
       }://${formattedHostname}:${port}`
 
-      if (isNodeDebugging) {
+      if (nodeDebugType) {
         const debugPort = getDebugPort()
         Log.info(
-          `the --inspect${
-            isNodeDebugging === 'brk' ? '-brk' : ''
-          } option was detected, the Next.js router server should be inspected at port ${debugPort}.`
+          `the --${nodeDebugType} option was detected, the Next.js router server should be inspected at port ${debugPort}.`
         )
       }
 
@@ -243,7 +241,7 @@ export async function startServer({
           server,
           hostname,
           minimalMode,
-          isNodeDebugging: Boolean(isNodeDebugging),
+          isNodeDebugging: Boolean(nodeDebugType),
           keepAliveTimeout,
           experimentalTestProxy: !!isExperimentalTestProxy,
           experimentalHttpsServer: !!selfSignedCertificate,

packages/next/src/server/lib/utils.ts

@@ -42,3 +42,23 @@ export function getPort(args: arg.Result<arg.Spec>): number {
 }
 
 export const RESTART_EXIT_CODE = 77
+
+export function checkNodeDebugType() {
+  let nodeDebugType = undefined
+
+  if (
+    process.execArgv.some((localArg) => localArg.startsWith('--inspect')) ||
+    process.env.NODE_OPTIONS?.match?.(/--inspect(=\S+)?( |$)/)
+  ) {
+    nodeDebugType = 'inspect'
+  }
+
+  if (
+    process.execArgv.some((localArg) => localArg.startsWith('--inspect-brk')) ||
+    process.env.NODE_OPTIONS?.match?.(/--inspect-brk(=\S+)?( |$)/)
+  ) {
+    nodeDebugType = 'inspect-brk'
+  }
+
+  return nodeDebugType
+}

packages/next/src/server/next.ts

@@ -25,7 +25,7 @@ import { PHASE_PRODUCTION_SERVER } from '../shared/lib/constants'
 import { getTracer } from './lib/trace/tracer'
 import { NextServerSpan } from './lib/trace/constants'
 import { formatUrl } from '../shared/lib/router/utils/format-url'
-import { checkIsNodeDebugging } from './lib/is-node-debugging'
+import { checkNodeDebugType } from './lib/utils'
 
 let ServerImpl: typeof Server
 
@@ -275,7 +275,7 @@ class NextCustomServer extends NextServer {
     const { getRequestHandlers } =
       require('./lib/start-server') as typeof import('./lib/start-server')
 
-    const isNodeDebugging = checkIsNodeDebugging()
+    const isNodeDebugging = !!checkNodeDebugType()
 
     const initResult = await getRequestHandlers({
       dir: this.options.dir!,

test/development/basic/node-builtins.test.ts

@@ -86,7 +86,7 @@ createNextDescribe(
       expect(parsedData.https).toBe(true)
       expect(parsedData.os).toBe('\n')
       expect(parsedData.path).toBe('/hello/world/test.txt')
-      expect(parsedData.process).toInclude('next-router-worker')
+      expect(parsedData.process).toInclude('next-server')
       expect(parsedData.querystring).toBe('a=b')
       expect(parsedData.stringDecoder).toBe(true)
       expect(parsedData.sys).toBe(true)
@@ -112,7 +112,7 @@ createNextDescribe(
       expect(parsedData.https).toBe(true)
       expect(parsedData.os).toBe('\n')
       expect(parsedData.path).toBe('/hello/world/test.txt')
-      expect(parsedData.process).toInclude('next-router-worker')
+      expect(parsedData.process).toInclude('next-server')
       expect(parsedData.querystring).toBe('a=b')
       expect(parsedData.stringDecoder).toBe(true)
       expect(parsedData.sys).toBe(true)