From b45bb335db5b3632329d6b41e5a790ff6f1a7ff7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Markb=C3=A5ge?= <sebastian@calyptus.eu>
Date: Thu, 11 Dec 2025 17:23:01 -0500
Subject: [PATCH] [Flight] Add extra loop protection (#35351)

In case we get into loops.
---
 packages/react-server/src/ReactFlightReplyServer.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/react-server/src/ReactFlightReplyServer.js b/packages/react-server/src/ReactFlightReplyServer.js
index 1831a35857..4d5a6da8b8 100644
--- a/packages/react-server/src/ReactFlightReplyServer.js
+++ b/packages/react-server/src/ReactFlightReplyServer.js
@@ -132,8 +132,10 @@ ReactPromise.prototype.then = function <T>(
         let inspectedValue = chunk.value;
         // Recursively check if the value is itself a ReactPromise and if so if it points
         // back to itself. This helps catch recursive thenables early error.
+        let cycleProtection = 0;
         while (inspectedValue instanceof ReactPromise) {
-          if (inspectedValue === chunk) {
+          cycleProtection++;
+          if (inspectedValue === chunk || cycleProtection > 1000) {
             if (typeof reject === 'function') {
               reject(new Error('Cannot have cyclic thenables.'));
             }