[Fiber] Move updatePriority tracking to renderers (#28751)

Currently updatePriority is tracked in the reconciler. `flushSync` is
going to be implemented reconciler agnostic soon and we need to move the
tracking of this state to the renderer and out of reconciler. This
change implements new renderer bin dings for getCurrentUpdatePriority
and setCurrentUpdatePriority.

I was originally going to have the getter also do the event priority
defaulting using window.event so we eliminate getCur rentEventPriority
but this makes all the callsites where we store the true current
updatePriority on the stack harder to work with so for now they remain
separate.

I also moved runWithPriority to the renderer since it really belongs
whereever the state is being managed and it is only currently exposed in
the DOM renderer.

Additionally the current update priority is not stored on
ReactDOMSharedInternals. While not particularly meaningful in this
change it opens the door to implementing `flushSync` outside of the
reconciler

packages/react-art/src/ReactFiberConfigART.js

@@ -5,12 +5,17 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+import type {EventPriority} from 'react-reconciler/src/ReactEventPriorities';
+
 import Transform from 'art/core/transform';
 import Mode from 'art/modes/current';
 
 import {TYPES, EVENT_TYPES, childrenAsString} from './ReactARTInternals';
 
-import {DefaultEventPriority} from 'react-reconciler/src/ReactEventPriorities';
+import {
+  DefaultEventPriority,
+  NoEventPriority,
+} from 'react-reconciler/src/ReactEventPriorities';
 
 const pooledTransform = new Transform();
 
@@ -336,8 +341,18 @@ export function shouldSetTextContent(type, props) {
   );
 }
 
-export function getCurrentEventPriority() {
-  return DefaultEventPriority;
+let currentUpdatePriority: EventPriority = NoEventPriority;
+
+export function setCurrentUpdatePriority(newPriority: EventPriority): void {
+  currentUpdatePriority = newPriority;
+}
+
+export function getCurrentUpdatePriority(): EventPriority {
+  return currentUpdatePriority;
+}
+
+export function resolveUpdatePriority(): EventPriority {
+  return currentUpdatePriority || DefaultEventPriority;
 }
 
 export function shouldAttemptEagerTransition() {

packages/react-dom-bindings/src/client/ReactDOMUpdatePriority.js

@@ -0,0 +1,55 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+import type {EventPriority} from 'react-reconciler/src/ReactEventPriorities';
+
+import {getEventPriority} from '../events/ReactDOMEventListener';
+import {
+  NoEventPriority,
+  DefaultEventPriority,
+} from 'react-reconciler/src/ReactEventPriorities';
+
+import ReactDOMSharedInternals from 'shared/ReactDOMSharedInternals';
+
+export function setCurrentUpdatePriority(
+  newPriority: EventPriority,
+  // Closure will consistently not inline this function when it has arity 1
+  // however when it has arity 2 even if the second arg is omitted at every
+  // callsite it seems to inline it even when the internal length of the function
+  // is much longer. I hope this is consistent enough to rely on across builds
+  IntentionallyUnusedArgument?: empty,
+): void {
+  ReactDOMSharedInternals.up = newPriority;
+}
+
+export function getCurrentUpdatePriority(): EventPriority {
+  return ReactDOMSharedInternals.up;
+}
+
+export function resolveUpdatePriority(): EventPriority {
+  const updatePriority = ReactDOMSharedInternals.up;
+  if (updatePriority !== NoEventPriority) {
+    return updatePriority;
+  }
+  const currentEvent = window.event;
+  if (currentEvent === undefined) {
+    return DefaultEventPriority;
+  }
+  return getEventPriority(currentEvent.type);
+}
+
+export function runWithPriority<T>(priority: EventPriority, fn: () => T): T {
+  const previousPriority = getCurrentUpdatePriority();
+  try {
+    setCurrentUpdatePriority(priority);
+    return fn();
+  } finally {
+    setCurrentUpdatePriority(previousPriority);
+  }
+}

packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js

@@ -7,7 +7,6 @@
  * @flow
  */
 
-import type {EventPriority} from 'react-reconciler/src/ReactEventPriorities';
 import type {DOMEventName} from '../events/DOMEventNames';
 import type {Fiber, FiberRoot} from 'react-reconciler/src/ReactInternalTypes';
 import type {
@@ -29,11 +28,15 @@ import type {
 
 import {NotPending} from 'react-dom-bindings/src/shared/ReactDOMFormActions';
 import {getCurrentRootHostContainer} from 'react-reconciler/src/ReactFiberHostContext';
-import {DefaultEventPriority} from 'react-reconciler/src/ReactEventPriorities';
 
 import hasOwnProperty from 'shared/hasOwnProperty';
 import {checkAttributeStringCoercion} from 'shared/CheckStringCoercion';
 
+export {
+  setCurrentUpdatePriority,
+  getCurrentUpdatePriority,
+  resolveUpdatePriority,
+} from './ReactDOMUpdatePriority';
 import {
   precacheFiberNode,
   updateFiberProps,
@@ -69,7 +72,6 @@ import {
 import {
   isEnabled as ReactBrowserEventEmitterIsEnabled,
   setEnabled as ReactBrowserEventEmitterSetEnabled,
-  getEventPriority,
 } from '../events/ReactDOMEventListener';
 import {SVG_NAMESPACE, MATH_NAMESPACE} from './DOMNamespaces';
 import {
@@ -572,14 +574,6 @@ export function createTextInstance(
   return textNode;
 }
 
-export function getCurrentEventPriority(): EventPriority {
-  const currentEvent = window.event;
-  if (currentEvent === undefined) {
-    return DefaultEventPriority;
-  }
-  return getEventPriority(currentEvent.type);
-}
-
 let currentPopstateTransitionEvent: Event | null = null;
 export function shouldAttemptEagerTransition(): boolean {
   const event = window.event;

packages/react-dom-bindings/src/events/ReactDOMEventListener.js

@@ -34,6 +34,10 @@ import {
 } from '../client/ReactDOMComponentTree';
 
 import {dispatchEventForPluginEventSystem} from './DOMPluginEventSystem';
+import {
+  getCurrentUpdatePriority,
+  setCurrentUpdatePriority,
+} from '../client/ReactDOMUpdatePriority';
 
 import {
   getCurrentPriorityLevel as getCurrentSchedulerPriorityLevel,
@@ -48,8 +52,6 @@ import {
   ContinuousEventPriority,
   DefaultEventPriority,
   IdleEventPriority,
-  getCurrentUpdatePriority,
-  setCurrentUpdatePriority,
 } from 'react-reconciler/src/ReactEventPriorities';
 import ReactSharedInternals from 'shared/ReactSharedInternals';
 import {isRootDehydrated} from 'react-reconciler/src/ReactFiberShellHydration';
@@ -115,9 +117,9 @@ function dispatchDiscreteEvent(
   container: EventTarget,
   nativeEvent: AnyNativeEvent,
 ) {
-  const previousPriority = getCurrentUpdatePriority();
   const prevTransition = ReactCurrentBatchConfig.transition;
   ReactCurrentBatchConfig.transition = null;
+  const previousPriority = getCurrentUpdatePriority();
   try {
     setCurrentUpdatePriority(DiscreteEventPriority);
     dispatchEvent(domEventName, eventSystemFlags, container, nativeEvent);
@@ -133,9 +135,9 @@ function dispatchContinuousEvent(
   container: EventTarget,
   nativeEvent: AnyNativeEvent,
 ) {
-  const previousPriority = getCurrentUpdatePriority();
   const prevTransition = ReactCurrentBatchConfig.transition;
   ReactCurrentBatchConfig.transition = null;
+  const previousPriority = getCurrentUpdatePriority();
   try {
     setCurrentUpdatePriority(ContinuousEventPriority);
     dispatchEvent(domEventName, eventSystemFlags, container, nativeEvent);

packages/react-dom-bindings/src/events/ReactDOMEventReplaying.js

@@ -37,15 +37,15 @@ import {HostRoot, SuspenseComponent} from 'react-reconciler/src/ReactWorkTags';
 import {isHigherEventPriority} from 'react-reconciler/src/ReactEventPriorities';
 import {isRootDehydrated} from 'react-reconciler/src/ReactFiberShellHydration';
 import {dispatchReplayedFormAction} from './plugins/FormActionEventPlugin';
+import {
+  getCurrentUpdatePriority,
+  runWithPriority as attemptHydrationAtPriority,
+} from '../client/ReactDOMUpdatePriority';
 
 import {
   attemptContinuousHydration,
   attemptHydrationAtCurrentPriority,
 } from 'react-reconciler/src/ReactFiberReconciler';
-import {
-  runWithPriority as attemptHydrationAtPriority,
-  getCurrentUpdatePriority,
-} from 'react-reconciler/src/ReactEventPriorities';
 
 // TODO: Upgrade this definition once we're on a newer version of Flow that
 // has this definition built-in.

packages/react-dom/src/ReactDOMSharedInternals.js

@@ -7,8 +7,11 @@
  * @flow
  */
 
+import type {EventPriority} from 'react-reconciler/src/ReactEventPriorities';
 import type {HostDispatcher} from './shared/ReactDOMTypes';
 
+import {NoEventPriority} from 'react-reconciler/src/ReactEventPriorities';
+
 type InternalsType = {
   usingClientEntryPoint: boolean,
   Events: [any, any, any, any, any, any],
@@ -20,6 +23,7 @@ type InternalsType = {
     | ((
         componentOrElement: React$Component<any, any>,
       ) => null | Element | Text),
+  up /* currentUpdatePriority */: EventPriority,
 };
 
 function noop() {}
@@ -34,13 +38,14 @@ const DefaultDispatcher: HostDispatcher = {
   preinitModuleScript: noop,
 };
 
-const Internals: InternalsType = ({
+const Internals: InternalsType = {
   usingClientEntryPoint: false,
-  Events: null,
+  Events: (null: any),
   ReactDOMCurrentDispatcher: {
     current: DefaultDispatcher,
   },
   findDOMNode: null,
-}: any);
+  up /* currentUpdatePriority */: NoEventPriority,
+};
 
 export default Internals;

packages/react-dom/src/client/ReactDOM.js

@@ -20,14 +20,14 @@ import {
   isValidContainer,
 } from './ReactDOMRoot';
 import {createEventHandle} from 'react-dom-bindings/src/client/ReactDOMEventHandle';
+import {runWithPriority} from 'react-dom-bindings/src/client/ReactDOMUpdatePriority';
 
 import {
   flushSync as flushSyncWithoutWarningIfAlreadyRendering,
   isAlreadyRendering,
   injectIntoDevTools,
   findHostInstance,
 } from 'react-reconciler/src/ReactFiberReconciler';
-import {runWithPriority} from 'react-reconciler/src/ReactEventPriorities';
 import {createPortal as createPortalImpl} from 'react-reconciler/src/ReactPortal';
 import {canUseDOM} from 'shared/ExecutionEnvironment';
 import ReactVersion from 'shared/ReactVersion';

packages/react-native-renderer/src/ReactFiberConfigFabric.js

@@ -15,6 +15,7 @@ import type {
 import {create, diff} from './ReactNativeAttributePayload';
 import {dispatchEvent} from './ReactFabricEventEmitter';
 import {
+  NoEventPriority,
   DefaultEventPriority,
   DiscreteEventPriority,
   type EventPriority,
@@ -311,7 +312,20 @@ export function shouldSetTextContent(type: string, props: Props): boolean {
   return false;
 }
 
-export function getCurrentEventPriority(): EventPriority {
+let currentUpdatePriority: EventPriority = NoEventPriority;
+export function setCurrentUpdatePriority(newPriority: EventPriority): void {
+  currentUpdatePriority = newPriority;
+}
+
+export function getCurrentUpdatePriority(): EventPriority {
+  return currentUpdatePriority;
+}
+
+export function resolveUpdatePriority(): EventPriority {
+  if (currentUpdatePriority !== NoEventPriority) {
+    return currentUpdatePriority;
+  }
+
   const currentEventPriority = fabricGetCurrentEventPriority
     ? fabricGetCurrentEventPriority()
     : null;

packages/react-native-renderer/src/ReactFiberConfigNative.js

@@ -26,6 +26,7 @@ import ReactNativeFiberHostComponent from './ReactNativeFiberHostComponent';
 
 import {
   DefaultEventPriority,
+  NoEventPriority,
   type EventPriority,
 } from 'react-reconciler/src/ReactEventPriorities';
 import type {Fiber} from 'react-reconciler/src/ReactInternalTypes';
@@ -253,7 +254,19 @@ export function shouldSetTextContent(type: string, props: Props): boolean {
   return false;
 }
 
-export function getCurrentEventPriority(): EventPriority {
+let currentUpdatePriority: EventPriority = NoEventPriority;
+export function setCurrentUpdatePriority(newPriority: EventPriority): void {
+  currentUpdatePriority = newPriority;
+}
+
+export function getCurrentUpdatePriority(): EventPriority {
+  return currentUpdatePriority;
+}
+
+export function resolveUpdatePriority(): EventPriority {
+  if (currentUpdatePriority !== NoEventPriority) {
+    return currentUpdatePriority;
+  }
   return DefaultEventPriority;
 }
 

packages/react-noop-renderer/src/createReactNoop.js

@@ -21,12 +21,14 @@ import type {
 import type {UpdateQueue} from 'react-reconciler/src/ReactFiberClassUpdateQueue';
 import type {ReactNodeList} from 'shared/ReactTypes';
 import type {RootTag} from 'react-reconciler/src/ReactRootTags';
+import type {EventPriority} from 'react-reconciler/src/ReactEventPriorities';
 
 import * as Scheduler from 'scheduler/unstable_mock';
 import {REACT_FRAGMENT_TYPE, REACT_ELEMENT_TYPE} from 'shared/ReactSymbols';
 import isArray from 'shared/isArray';
 import {checkPropStringCoercion} from 'shared/CheckStringCoercion';
 import {
+  NoEventPriority,
   DefaultEventPriority,
   IdleEventPriority,
   ConcurrentRoot,
@@ -512,7 +514,13 @@ function createReactNoop(reconciler: Function, useMutation: boolean) {
 
     resetAfterCommit(): void {},
 
-    getCurrentEventPriority() {
+    setCurrentUpdatePriority,
+    getCurrentUpdatePriority,
+
+    resolveUpdatePriority() {
+      if (currentUpdatePriority !== NoEventPriority) {
+        return currentUpdatePriority;
+      }
       return currentEventPriority;
     },
 
@@ -786,6 +794,15 @@ function createReactNoop(reconciler: Function, useMutation: boolean) {
   const roots = new Map();
   const DEFAULT_ROOT_ID = '<default>';
 
+  let currentUpdatePriority = NoEventPriority;
+  function setCurrentUpdatePriority(newPriority: EventPriority): void {
+    currentUpdatePriority = newPriority;
+  }
+
+  function getCurrentUpdatePriority(): EventPriority {
+    return currentUpdatePriority;
+  }
+
   let currentEventPriority = DefaultEventPriority;
 
   function createJSXElementForTestComparison(type, props) {
@@ -1223,7 +1240,18 @@ function createReactNoop(reconciler: Function, useMutation: boolean) {
       return Scheduler.unstable_flushExpired();
     },
 
-    unstable_runWithPriority: NoopRenderer.runWithPriority,
+    unstable_runWithPriority: function runWithPriority<T>(
+      priority: EventPriority,
+      fn: () => T,
+    ): T {
+      const previousPriority = getCurrentUpdatePriority();
+      try {
+        setCurrentUpdatePriority(priority);
+        return fn();
+      } finally {
+        setCurrentUpdatePriority(previousPriority);
+      }
+    },
 
     batchedUpdates: NoopRenderer.batchedUpdates,