fix(dev): reap every pooled fork on shutdown

Author: danielroe

packages/nuxt-cli/src/dev/index.ts

@@ -27,6 +27,11 @@ class IPC {
 constructor(){
 // only kill process if it is a fork
 if(this.enabled){
+// Without a parent there is nobody to reap this process, and it may be
+// holding the dev server port or the inspector port.
+process.once('disconnect',()=>{
+process.exit(0)
+})
 process.once('unhandledRejection',(reason)=>{
 this.send({type: 'nuxt:internal:dev:rejection',message: reasoninstanceofError ? reason.toString() : 'Unhandled Rejection'})
 process.exit()

packages/nuxt-cli/src/dev/pool.ts

@@ -5,7 +5,6 @@ import type { NuxtDevContext, NuxtDevIPCMessage } from './utils'
 
 import{fork}from'node:child_process'
 importprocessfrom'node:process'
-import{isDeno}from'std-env'
 import{debug}from'../utils/logger'
 
 interfaceForkPoolOptions{
@@ -195,7 +194,8 @@ export class ForkPool {
 constwasAlive=fork.state!=='dead'&&!!fork.process&&fork.process.exitCode===null
 fork.state='dead'
 if(fork.process){
-fork.process.kill(signal===0&&isDeno ? 'SIGTERM' : signal)
+// signal 0 only probes for liveness, so map the `exit` case onto a real signal
+fork.process.kill(signal===0 ? 'SIGTERM' : signal)
 }
 this.removeFork(fork)
 
@@ -223,7 +223,8 @@ export class ForkPool {
 }
 
 privatekillAll(signal: NodeJS.Signals|number): void{
-for(constforkofthis.pool){
+// `killFork` mutates the pool, so iterate over a snapshot
+for(constforkof[...this.pool]){
 this.killFork(fork,signal)
 }
 }

packages/nuxt-cli/test/fixtures/fork-pool-entry.mjs

@@ -0,0 +1,6 @@
+importprocessfrom'node:process'
+
+// Node refs the IPC channel while a `message` listener is attached, which is
+// what keeps this stand-in for a warm fork alive after it reports readiness.
+process.on('message',()=>{})
+process.send({type: 'nuxt:internal:dev:fork-ready'})

packages/nuxt-cli/test/unit/fork-pool.spec.ts

@@ -0,0 +1,46 @@
+importtype{ChildProcess}from'node:child_process'
+import{fileURLToPath}from'node:url'
+import{afterEach,describe,expect,it,vi}from'vitest'
+
+import{ForkPool}from'../../src/dev/pool'
+
+constdevEntry=fileURLToPath(newURL('../fixtures/fork-pool-entry.mjs',import.meta.url))
+
+constpools: ForkPool[]=[]
+
+functioncreatePool(poolSize?: number){
+globalThis.__nuxt_cli__={ ...globalThis.__nuxt_cli__, devEntry }astypeofglobalThis.__nuxt_cli__
+constpool=newForkPool({rawArgs: [], poolSize,listenOverrides: {}})
+pools.push(pool)
+returnpool
+}
+
+asyncfunctionwaitForReady(pool: ForkPool,count: number){
+awaitvi.waitFor(()=>{
+expect(pool.getStats().ready).toBe(count)
+},{timeout: 20_000,interval: 25})
+}
+
+afterEach(async()=>{
+for(constpoolofpools.splice(0)){
+await(poolasunknownas{killAll: (signal: number)=>void}).killAll(0)
+}
+})
+
+describe('forkPool',()=>{
+it('should kill every fork on shutdown',{timeout: 30_000},async()=>{
+constpool=createPool(3)
+pool.startWarming()
+awaitwaitForReady(pool,3)
+
+constprocesses=(poolasunknownas{pool: Array<{process: ChildProcess}>}).pool.map(f=>f.process)
+;(poolasunknownas{killAll: (signal: number)=>void}).killAll(0)
+
+awaitvi.waitFor(()=>{
+for(constchildofprocesses){
+expect(child.killed).toBe(true)
+}
+},{timeout: 10_000,interval: 25})
+expect(pool.getStats().total).toBe(0)
+})
+})