From 689af6cd90350af25ce708657040f5300a1136e7 Mon Sep 17 00:00:00 2001
From: jshaofa-ui <jshaofa@gmail.com>
Date: Tue, 12 May 2026 21:23:48 +0800
Subject: [PATCH] Fix: ReactDOM.preloadModule crash with repeated custom as
 value

The repeated custom-`as` path checks `moduleUnknownResources` but then
reads the bucket from `unknownResources`, so the bucket can be undefined.

Fixed by reading from `moduleUnknownResources` instead of `unknownResources`
on line 6555 of ReactFizzConfigDOM.js.

Fixes facebook/react#36440
---
 packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js b/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js
index 691e49e563fd..b273d9a89edb 100644
--- a/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js
+++ b/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js
@@ -6552,7 +6552,7 @@ function preloadModule(
           resumableState.moduleUnknownResources.hasOwnProperty(as);
         let resources;
         if (hasAsType) {
-          resources = resumableState.unknownResources[as];
+          resources = resumableState.moduleUnknownResources[as];
           if (resources.hasOwnProperty(key)) {
             // we can return if we already have this resource
             return;