ensure webpack worker exits bubble to parent process (#72921)

This matches the handling added in #70997 but for the Webpack build
worker. This unifies the worker code to be the same as the one for the
static export worker which already handles this case.

When the worker exits ungracefully, we need to propagate an error signal
to the parent process so that it doesn't hang.

Fixes #67097
Closes NDX-485
Closes #67154

packages/next/src/build/webpack-build/index.ts

@@ -2,9 +2,8 @@ import type { COMPILER_INDEXES } from '../../shared/lib/constants'
 import * as Log from '../output/log'
 import { NextBuildContext } from '../build-context'
 import type { BuildTraceContext } from '../webpack/plugins/next-trace-entrypoints-plugin'
-import { Worker } from 'next/dist/compiled/jest-worker'
+import { Worker } from '../../lib/worker'
 import origDebug from 'next/dist/compiled/debug'
-import type { ChildProcess } from 'child_process'
 import path from 'path'
 import { exportTraceState, recordTraceEvents } from '../../trace'
 
@@ -38,44 +37,24 @@ async function webpackBuildWithWorker(
 
   prunedBuildContext.pluginState = pluginState
 
-  const getWorker = (compilerName: string) => {
-    const _worker = new Worker(path.join(__dirname, 'impl.js'), {
-      exposedMethods: ['workerMain'],
-      numWorkers: 1,
-      maxRetries: 0,
-      forkOptions: {
-        env: {
-          ...process.env,
-          NEXT_PRIVATE_BUILD_WORKER: '1',
-        },
+  const worker = new Worker(path.join(__dirname, 'impl.js'), {
+    exposedMethods: ['workerMain'],
+    numWorkers: 1,
+    maxRetries: 0,
+    forkOptions: {
+      env: {
+        ...process.env,
+        NEXT_PRIVATE_BUILD_WORKER: '1',
       },
-    }) as Worker & typeof import('./impl')
-    _worker.getStderr().pipe(process.stderr)
-    _worker.getStdout().pipe(process.stdout)
-
-    for (const worker of ((_worker as any)._workerPool?._workers || []) as {
-      _child: ChildProcess
-    }[]) {
-      worker._child.on('exit', (code, signal) => {
-        if (code || (signal && signal !== 'SIGINT')) {
-          debug(
-            `Compiler ${compilerName} unexpectedly exited with code: ${code} and signal: ${signal}`
-          )
-        }
-      })
-    }
-
-    return _worker
-  }
+    },
+  }) as Worker & typeof import('./impl')
 
   const combinedResult = {
     duration: 0,
     buildTraceContext: {} as BuildTraceContext,
   }
 
   for (const compilerName of compilerNames) {
-    const worker = getWorker(compilerName)
-
     const curResult = await worker.workerMain({
       buildContext: prunedBuildContext,
       compilerName,
@@ -88,8 +67,6 @@ async function webpackBuildWithWorker(
     if (nextBuildSpan && curResult.debugTraceEvents) {
       recordTraceEvents(curResult.debugTraceEvents)
     }
-    // destroy worker so it's not sticking around using memory
-    await worker.end()
 
     // Update plugin state
     pluginState = deepMerge(pluginState, curResult.pluginState)
@@ -125,6 +102,9 @@ async function webpackBuildWithWorker(
     }
   }
 
+  // destroy worker so it's not sticking around using memory
+  worker.end()
+
   if (compilerNames.length === 3) {
     Log.event('Compiled successfully')
   }