From d74f061b6908e4841b2eb09c296ca4658dbdd38e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Markb=C3=A5ge?= <sebastian@calyptus.eu>
Date: Wed, 1 Oct 2025 21:58:13 -0400
Subject: [PATCH] [Fiber] Clean up ViewTransition when it fails to start
 (#34676)

The View Transition docs were unclear about this but apparently the
`finished` promise never settles if the animation never started. So if
there's an error that rejects the `ready` promise, we'll never run the
clean up which can cause it to stall.

Fixes #34662.

However, ultimately that is caused by Chrome stalling our default
`onDefaultTransitionIndicator` but it should be unblocked after 10
seconds, not a minute.
---
 .../src/client/ReactFiberConfigDOM.js            | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js b/packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js
index 7d28dc43ca..0f75d5f8cd 100644
--- a/packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js
+++ b/packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js
@@ -2279,6 +2279,11 @@ export function startViewTransition(
       spawnedWorkCallback();
     };
     const handleError = (error: mixed) => {
+      // $FlowFixMe[prop-missing]
+      if (ownerDocument.__reactViewTransition === transition) {
+        // $FlowFixMe[prop-missing]
+        ownerDocument.__reactViewTransition = null;
+      }
       try {
         error = customizeViewTransitionError(error, false);
         if (error !== null) {
@@ -2293,6 +2298,9 @@ export function startViewTransition(
         layoutCallback();
         // Skip afterMutationCallback() since we're not animating.
         spawnedWorkCallback();
+        if (enableProfilerTimer) {
+          finishedAnimation();
+        }
       }
     };
     transition.ready.then(readyCallback, handleError);
@@ -2699,6 +2707,11 @@ export function startGestureTransition(
         ? () => requestAnimationFrame(readyCallback)
         : readyCallback;
     const handleError = (error: mixed) => {
+      // $FlowFixMe[prop-missing]
+      if (ownerDocument.__reactViewTransition === transition) {
+        // $FlowFixMe[prop-missing]
+        ownerDocument.__reactViewTransition = null;
+      }
       try {
         error = customizeViewTransitionError(error, true);
         if (error !== null) {
@@ -2713,6 +2726,9 @@ export function startGestureTransition(
         // Skip readyCallback() and go straight to animateCallbck() since we're not animating.
         // animateCallback() is still required to restore states.
         animateCallback();
+        if (enableProfilerTimer) {
+          finishedAnimation();
+        }
       }
     };
     transition.ready.then(readyForAnimations, handleError);