From c72c2beaa7003b7f4cb2d268e96ebd5cd1094c1f Mon Sep 17 00:00:00 2001
From: Luca Casonato <hello@lcas.dev>
Date: Tue, 27 Aug 2024 17:37:04 +0200
Subject: [PATCH] Wait until process exit in esbuild.stop()

This changes `esbuild.stop()` to only resolve the returned promise when the child process has actually exited.

This is useful for when you have some resource sanitization in place that checks that the child process has actually been closed.
---
 lib/npm/node.ts | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/lib/npm/node.ts b/lib/npm/node.ts
index 663937f88b5..54af055975f 100644
--- a/lib/npm/node.ts
+++ b/lib/npm/node.ts
@@ -220,10 +220,9 @@ export let analyzeMetafileSync: typeof types.analyzeMetafileSync = (metafile, op
   return result!
 }
 
-export const stop = () => {
-  if (stopService) stopService()
+export const stop = async () => {
+  if (stopService) await stopService()
   if (workerThreadService) workerThreadService.stop()
-  return Promise.resolve()
 }
 
 let initializeWasCalled = false
@@ -249,7 +248,7 @@ interface Service {
 
 let defaultWD = process.cwd()
 let longLivedService: Service | undefined
-let stopService: (() => void) | undefined
+let stopService: (() => Promise<void>) | undefined
 
 let ensureServiceIsRunning = (): Service => {
   if (longLivedService) return longLivedService
@@ -285,7 +284,17 @@ let ensureServiceIsRunning = (): Service => {
   stdout.on('data', readFromStdout)
   stdout.on('end', afterClose)
 
-  stopService = () => {
+  stopService = async () => {
+    const exited = new Promise<void>(resolve => {
+      if (child.exitCode !== null || child.signalCode !== null) {
+        resolve()
+      } else {
+        // Re-ref the child so that this process's event loop doesn't starve
+        // if the user waits for the `stop` promise to resolve.
+        refs.ref()
+        child.on('exit', resolve)
+      }
+    })
     // Close all resources related to the subprocess.
     stdin.destroy()
     stdout.destroy()
@@ -293,6 +302,7 @@ let ensureServiceIsRunning = (): Service => {
     initializeWasCalled = false
     longLivedService = undefined
     stopService = undefined
+    await exited
   }
 
   let refCount = 0