From 1fcf768d0a4266a031ad3f407b4f512755c23100 Mon Sep 17 00:00:00 2001
From: Daniil Gaponov <dagaponov@yandex-team.ru>
Date: Thu, 10 Jul 2025 21:19:07 +0200
Subject: [PATCH] fix: memory leaks from worker recompilation with HMR

Add alreadyCompiled flag to prevent unnecessary worker rebuilds
during development with Hot Module Replacement, which was causing
memory leaks in both webpack and rspack.
---
 .../src/plugins/AddWorkerEntryPointPlugin.ts      | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/webpack-plugin/src/plugins/AddWorkerEntryPointPlugin.ts b/webpack-plugin/src/plugins/AddWorkerEntryPointPlugin.ts
index 68ad845c..2bd4ff60 100644
--- a/webpack-plugin/src/plugins/AddWorkerEntryPointPlugin.ts
+++ b/webpack-plugin/src/plugins/AddWorkerEntryPointPlugin.ts
@@ -13,11 +13,17 @@ function getCompilerHook(
 	{ id, entry, filename, chunkFilename, plugins }: IAddWorkerEntryPointPluginOptions
 ) {
 	const webpack = compiler.webpack ?? require('webpack');
+	let alreadyCompiled = false;
 
 	return function (
 		compilation: webpack.Compilation,
 		callback: (error?: Error | null | false) => void
 	) {
+		if (alreadyCompiled) {
+			callback();
+			return;
+		}
+
 		const outputOptions = {
 			filename,
 			chunkFilename,
@@ -33,7 +39,14 @@ function getCompilerHook(
 		new SingleEntryPlugin(compiler.context, entry, 'main').apply(childCompiler);
 		plugins.forEach((plugin) => plugin.apply(childCompiler));
 
-		childCompiler.runAsChild((err?: Error | null) => callback(err));
+		childCompiler.runAsChild((err?: Error | null) => {
+			if (err) {
+				callback(err);
+			} else {
+				alreadyCompiled = true;
+				callback();
+			}
+		});
 	};
 }