From 1a67780308aeac7fac60d822679a73eebd6f3a1d Mon Sep 17 00:00:00 2001
From: Jason Galea <jason@lecstor.com>
Date: Fri, 20 Mar 2026 12:18:40 +1000
Subject: [PATCH] fix(unplugin): prevent file handle leaks in Vitest (#1533)

Disable Babel config-file discovery (configFile: false) in
runBabelTransform() to stop leaked FILEHANDLE operations during
test run, and unref() the setInterval polling timer in
configureServer() so it does not block process exit in middleware
mode.
---
 packages/@stylexjs/unplugin/src/core.js | 1 +
 packages/@stylexjs/unplugin/src/vite.js | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/packages/@stylexjs/unplugin/src/core.js b/packages/@stylexjs/unplugin/src/core.js
index 5e47aac68..29426370e 100644
--- a/packages/@stylexjs/unplugin/src/core.js
+++ b/packages/@stylexjs/unplugin/src/core.js
@@ -283,6 +283,7 @@ export const unpluginFactory = (userOptions = {}, metaOptions) => {
   async function runBabelTransform(inputCode, filename, callerName) {
     const result = await transformAsync(inputCode, {
       babelrc: false,
+      configFile: false,
       filename,
       presets,
       plugins: [
diff --git a/packages/@stylexjs/unplugin/src/vite.js b/packages/@stylexjs/unplugin/src/vite.js
index 9510369c0..3d0c85494 100644
--- a/packages/@stylexjs/unplugin/src/vite.js
+++ b/packages/@stylexjs/unplugin/src/vite.js
@@ -87,6 +87,10 @@ function attachViteHooks(plugin) {
             } catch {}
           }
         }, 150);
+        // Unref the timer so it does not prevent the process from exiting
+        // (e.g. when Vitest runs the plugin in middleware mode without an
+        // HTTP server that emits 'close').
+        interval.unref();
         server.httpServer?.once('close', () => clearInterval(interval));
       }
     },