From bd28d5df6db86cc2bc2872b27fdf1eb988124a04 Mon Sep 17 00:00:00 2001
From: Spocke <spocke@moxiecode.com>
Date: Thu, 27 Aug 2026 11:44:27 +0200
Subject: [PATCH] TINYMCE-14841: Fixed React/Preact bundling issue

---
 CHANGELOG.md                                          | 3 +++
 modules/server/src/main/ts/bedrock/compiler/Rspack.ts | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3b5ade66..74e24e1f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Fixed
+- Tests using JSX failed with `React is not defined` when compiled with the rspack bundler. #TINYMCE-14841
+
 ## 17.0.0 - 2026-08-27
 
 ### Added
diff --git a/modules/server/src/main/ts/bedrock/compiler/Rspack.ts b/modules/server/src/main/ts/bedrock/compiler/Rspack.ts
index 4d394ebe..3f1c27a6 100644
--- a/modules/server/src/main/ts/bedrock/compiler/Rspack.ts
+++ b/modules/server/src/main/ts/bedrock/compiler/Rspack.ts
@@ -63,7 +63,7 @@ const getWebPackConfigTs = (tsConfigFile: string, scratchFile: string, dest: str
               target: 'es2022',
               transform: {
                 react: {
-                  runtime: 'classic',
+                  runtime: 'automatic',
                 },
               },
             },