Allow dev server to exit cleanly (SIGINT/SIGTERM)

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

@@ -35,6 +35,7 @@ import {
 } from '../lib/helpers/get-reserved-port'
 import os from 'os'
 import { once } from 'node:events'
+import { clearTimeout } from 'timers'
 
 export type NextDevOptions = {
   turbo?: boolean
@@ -57,13 +58,29 @@ let traceUploadUrl: string
 let sessionStopHandled = false
 let sessionStarted = Date.now()
 
+// How long should we wait for the child to cleanly exit after sending
+// SIGINT/SIGTERM to the child process before sending SIGKILL?
+const CHILD_EXIT_TIMEOUT_MS = parseInt(
+  process.env.NEXT_EXIT_TIMEOUT_MS ?? '100',
+  10
+)
+
 const handleSessionStop = async (signal: NodeJS.Signals | number | null) => {
-  if (child?.pid) child.kill(signal ?? 0)
+  if (signal != null && child?.pid) child.kill(signal)
   if (sessionStopHandled) return
   sessionStopHandled = true
 
-  if (child?.pid && child.exitCode === null && child.signalCode === null) {
+  if (
+    signal != null &&
+    child?.pid &&
+    child.exitCode === null &&
+    child.signalCode === null
+  ) {
+    let exitTimeout = setTimeout(() => {
+      child?.kill('SIGKILL')
+    }, CHILD_EXIT_TIMEOUT_MS)
     await once(child, 'exit').catch(() => {})
+    clearTimeout(exitTimeout)
   }
 
   try {
@@ -124,8 +141,8 @@ const handleSessionStop = async (signal: NodeJS.Signals | number | null) => {
   process.exit(0)
 }
 
-process.on('SIGINT', () => handleSessionStop('SIGKILL'))
-process.on('SIGTERM', () => handleSessionStop('SIGKILL'))
+process.on('SIGINT', () => handleSessionStop('SIGINT'))
+process.on('SIGTERM', () => handleSessionStop('SIGTERM'))
 
 // exit event must be synchronous
 process.on('exit', () => child?.kill('SIGKILL'))
@@ -291,7 +308,9 @@ const nextDev = async (
           }
           return startServer(startServerOptions)
         }
-        await handleSessionStop(signal)
+        // Call handler (e.g. upload telemetry). Don't try to send a signal to
+        // the child, as it has already exited.
+        await handleSessionStop(/* signal */ null)
       })
     })
   }

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

@@ -270,10 +270,20 @@ export async function startServer(
 
       try {
         const cleanupListeners = [() => new Promise((res) => server.close(res))]
+        let cleanupStarted = false
         const cleanup = () => {
-          debug('start-server process cleanup')
+          if (cleanupStarted) {
+            // We can get duplicate signals, e.g. when `ctrl+c` is used in an
+            // interactive shell (i.e. bash, zsh), the shell will recursively
+            // send SIGINT to children. The parent `next-dev` process will also
+            // send us SIGINT.
+            return
+          }
+          cleanupStarted = true
           ;(async () => {
+            debug('start-server process cleanup')
             await Promise.all(cleanupListeners.map((f) => f()))
+            debug('start-server process cleanup finished')
             process.exit(0)
           })()
         }

test/production/graceful-shutdown/index.test.ts

@@ -100,7 +100,11 @@ describe('Graceful Shutdown', () => {
       app = await initNextServerScript(
         serverFile,
         /- Local:/,
-        { ...process.env, PORT: appPort.toString() },
+        {
+          ...process.env,
+          NEXT_EXIT_TIMEOUT_MS: '10',
+          PORT: appPort.toString(),
+        },
         undefined,
         { cwd: next.testDir }
       )