[pull] main from facebook:main

fixtures/view-transition/src/components/Transitions.module.css

@@ -56,10 +56,10 @@
 }
 
 ::view-transition-new(.enter-slide-right):only-child {
-  animation: enter-slide-right ease-in 0.25s;
+  animation: enter-slide-right ease-in 0.25s forwards;
 }
 ::view-transition-old(.exit-slide-left):only-child {
-  animation: exit-slide-left ease-in 0.25s;
+  animation: exit-slide-left ease-in 0.25s forwards;
 }
 
 :root:active-view-transition-type(navigation-back) {

packages/react-devtools-shared/src/backend/fiber/renderer.js

@@ -1516,7 +1516,7 @@ export function attach(
       currentRoot = rootInstance;
       unmountInstanceRecursively(rootInstance);
       rootToFiberInstanceMap.delete(root);
-      flushPendingEvents(root);
+      flushPendingEvents();
       currentRoot = (null: any);
     });
 
@@ -1541,7 +1541,7 @@ export function attach(
       currentRoot = newRoot;
       setRootPseudoKey(currentRoot.id, root.current);
       mountFiberRecursively(root.current, false);
-      flushPendingEvents(root);
+      flushPendingEvents();
       currentRoot = (null: any);
     });
 
@@ -2099,7 +2099,7 @@ export function attach(
     }
   }
 
-  function flushPendingEvents(root: Object): void {
+  function flushPendingEvents(): void {
     if (shouldBailoutWithPendingOperations()) {
       // If we aren't profiling, we can just bail out here.
       // No use sending an empty update over the bridge.
@@ -2902,16 +2902,32 @@ export function attach(
           // Let's remove it from the parent SuspenseNode.
           const ioInfo = asyncInfo.awaited;
           const suspendedBySet = parentSuspenseNode.suspendedBy.get(ioInfo);
+
           if (
             suspendedBySet === undefined ||
             !suspendedBySet.delete(instance)
           ) {
-            throw new Error(
-              'We are cleaning up async info that was not on the parent Suspense boundary. ' +
-                'This is a bug in React.',
-            );
+            // A boundary can await the same IO multiple times.
+            // We still want to error if we're trying to remove IO that isn't present on
+            // this boundary so we need to check if we've already removed it.
+            // We're assuming previousSuspendedBy is a small array so this should be faster
+            // than allocating and maintaining a Set.
+            let alreadyRemovedIO = false;
+            for (let j = 0; j < i; j++) {
+              const removedIOInfo = previousSuspendedBy[j].awaited;
+              if (removedIOInfo === ioInfo) {
+                alreadyRemovedIO = true;
+                break;
+              }
+            }
+            if (!alreadyRemovedIO) {
+              throw new Error(
+                'We are cleaning up async info that was not on the parent Suspense boundary. ' +
+                  'This is a bug in React.',
+              );
+            }
           }
-          if (suspendedBySet.size === 0) {
+          if (suspendedBySet !== undefined && suspendedBySet.size === 0) {
             parentSuspenseNode.suspendedBy.delete(asyncInfo.awaited);
           }
           if (
@@ -5336,7 +5352,7 @@ export function attach(
 
         mountFiberRecursively(root.current, false);
 
-        flushPendingEvents(root);
+        flushPendingEvents();
 
         needsToFlushComponentLogs = false;
         currentRoot = (null: any);
@@ -5439,6 +5455,9 @@ export function attach(
       unmountInstanceRecursively(rootInstance);
       removeRootPseudoKey(currentRoot.id);
       rootToFiberInstanceMap.delete(root);
+    } else if (!prevWasMounted && !nextIsMounted) {
+      // We don't need this root anymore.
+      rootToFiberInstanceMap.delete(root);
     }
 
     if (isProfiling && isProfilingSupported) {
@@ -5462,7 +5481,7 @@ export function attach(
     }
 
     // We're done here.
-    flushPendingEvents(root);
+    flushPendingEvents();
 
     needsToFlushComponentLogs = false;