Work-in-progress

packages/react-cache/src/LRU.js

@@ -11,7 +11,10 @@ import * as Scheduler from 'scheduler';
 
 // Intentionally not named imports because Rollup would
 // use dynamic dispatch for CommonJS interop named imports.
-const {unstable_scheduleCallback: scheduleCallback} = Scheduler;
+const {
+  unstable_scheduleCallback: scheduleCallback,
+  unstable_IdlePriority: IdlePriority,
+} = Scheduler;
 
 type Entry<T> = {|
   value: T,
@@ -34,7 +37,7 @@ export function createLRU<T>(limit: number) {
       // The cache size exceeds the limit. Schedule a callback to delete the
       // least recently used entries.
       cleanUpIsScheduled = true;
-      scheduleCallback(cleanUp);
+      scheduleCallback(IdlePriority, cleanUp);
     }
   }
 

packages/react-dom/src/__tests__/ReactDOMSuspensePlaceholder-test.js

@@ -14,6 +14,7 @@ let ReactDOM;
 let Suspense;
 let ReactCache;
 let ReactTestUtils;
+let Scheduler;
 let TextResource;
 let act;
 
@@ -26,6 +27,7 @@ describe('ReactDOMSuspensePlaceholder', () => {
     ReactDOM = require('react-dom');
     ReactCache = require('react-cache');
     ReactTestUtils = require('react-dom/test-utils');
+    Scheduler = require('scheduler');
     act = ReactTestUtils.act;
     Suspense = React.Suspense;
     container = document.createElement('div');
@@ -94,6 +96,8 @@ describe('ReactDOMSuspensePlaceholder', () => {
 
     await advanceTimers(1000);
 
+    Scheduler.flushAll();
+
     expect(divs[0].current.style.display).toEqual('');
     expect(divs[1].current.style.display).toEqual('');
     // This div's display was set with a prop.
@@ -115,6 +119,8 @@ describe('ReactDOMSuspensePlaceholder', () => {
 
     await advanceTimers(1000);
 
+    Scheduler.flushAll();
+
     expect(container.textContent).toEqual('ABC');
   });
 
@@ -160,6 +166,8 @@ describe('ReactDOMSuspensePlaceholder', () => {
 
       await advanceTimers(1000);
 
+      Scheduler.flushAll();
+
       expect(container.innerHTML).toEqual(
         '<span style="display: inline;">Sibling</span><span style="">Async</span>',
       );

packages/react-reconciler/src/ReactDebugFiberPerf.js

@@ -253,7 +253,7 @@ export function stopRequestCallbackTimer(
   expirationTime: number,
 ): void {
   if (enableUserTimingAPI) {
-    if (supportsUserTiming) {
+    if (supportsUserTiming && isWaitingForCallback) {
       isWaitingForCallback = false;
       const warning = didExpire ? 'React was blocked by main thread' : null;
       endMark(

packages/react-reconciler/src/ReactFiberExpirationTime.js

@@ -7,8 +7,17 @@
  * @flow
  */
 
+import type {ReactPriorityLevel} from './SchedulerWithReactIntegration';
+
 import MAX_SIGNED_31_BIT_INT from './maxSigned31BitInt';
 
+import {
+  ImmediatePriority,
+  UserBlockingPriority,
+  NormalPriority,
+  IdlePriority,
+} from './SchedulerWithReactIntegration';
+
 export type ExpirationTime = number;
 
 export const NoWork = 0;
@@ -46,6 +55,8 @@ function computeExpirationBucket(
   );
 }
 
+// TODO: This corresponds to Scheduler's NormalPriority, not LowPriority. Update
+// the names to reflect.
 export const LOW_PRIORITY_EXPIRATION = 5000;
 export const LOW_PRIORITY_BATCH_SIZE = 250;
 
@@ -80,3 +91,31 @@ export function computeInteractiveExpiration(currentTime: ExpirationTime) {
     HIGH_PRIORITY_BATCH_SIZE,
   );
 }
+
+export function inferPriorityFromExpirationTime(
+  currentTime: ExpirationTime,
+  expirationTime: ExpirationTime,
+): ReactPriorityLevel {
+  if (expirationTime === Sync) {
+    return ImmediatePriority;
+  }
+  if (expirationTime === Never) {
+    return IdlePriority;
+  }
+  const msUntil =
+    msToExpirationTime(expirationTime) - msToExpirationTime(currentTime);
+  if (msUntil <= 0) {
+    return ImmediatePriority;
+  }
+  if (msUntil <= HIGH_PRIORITY_EXPIRATION) {
+    return UserBlockingPriority;
+  }
+  if (msUntil <= LOW_PRIORITY_EXPIRATION) {
+    return NormalPriority;
+  }
+
+  // TODO: Handle LowPriority
+
+  // Assume anything lower has idle priority
+  return IdlePriority;
+}

packages/react-reconciler/src/ReactFiberReconciler.js

@@ -43,7 +43,6 @@ import {
   requestCurrentTime,
   computeExpirationForFiber,
   scheduleWork,
-  requestWork,
   flushRoot,
   batchedUpdates,
   unbatchedUpdates,
@@ -300,7 +299,6 @@ export function updateContainer(
 
 export {
   flushRoot,
-  requestWork,
   computeUniqueAsyncExpiration,
   batchedUpdates,
   unbatchedUpdates,

packages/react-reconciler/src/ReactFiberRoot.js

@@ -83,6 +83,13 @@ type BaseFiberRootProperties = {|
   firstBatch: Batch | null,
   // Linked-list of roots
   nextScheduledRoot: FiberRoot | null,
+
+  // New Scheduler fields
+  callbackNode: *,
+  callbackExpirationTime: ExpirationTime,
+  firstPendingTime: ExpirationTime,
+  lastPendingTime: ExpirationTime,
+  pingTime: ExpirationTime,
 |};
 
 // The following attributes are only used by interaction tracing builds.
@@ -145,6 +152,12 @@ export function createFiberRoot(
       interactionThreadID: unstable_getThreadID(),
       memoizedInteractions: new Set(),
       pendingInteractionMap: new Map(),
+
+      callbackNode: null,
+      callbackExpirationTime: NoWork,
+      firstPendingTime: NoWork,
+      lastPendingTime: NoWork,
+      pingTime: NoWork,
     }: FiberRoot);
   } else {
     root = ({
@@ -172,6 +185,12 @@ export function createFiberRoot(
       expirationTime: NoWork,
       firstBatch: null,
       nextScheduledRoot: null,
+
+      callbackNode: null,
+      callbackExpirationTime: NoWork,
+      firstPendingTime: NoWork,
+      lastPendingTime: NoWork,
+      pingTime: NoWork,
     }: BaseFiberRootProperties);
   }
 

packages/react-reconciler/src/ReactFiberScheduler.js

@@ -22,7 +22,6 @@ import {
   markLegacyErrorBoundaryAsFailed as markLegacyErrorBoundaryAsFailed_old,
   isAlreadyFailedLegacyErrorBoundary as isAlreadyFailedLegacyErrorBoundary_old,
   scheduleWork as scheduleWork_old,
-  requestWork as requestWork_old,
   flushRoot as flushRoot_old,
   batchedUpdates as batchedUpdates_old,
   unbatchedUpdates as unbatchedUpdates_old,
@@ -35,6 +34,7 @@ import {
   computeUniqueAsyncExpiration as computeUniqueAsyncExpiration_old,
   flushPassiveEffects as flushPassiveEffects_old,
   warnIfNotCurrentlyBatchingInDev as warnIfNotCurrentlyBatchingInDev_old,
+  inferStartTimeFromExpirationTime as inferStartTimeFromExpirationTime_old,
 } from './ReactFiberScheduler.old';
 
 import {
@@ -50,7 +50,6 @@ import {
   markLegacyErrorBoundaryAsFailed as markLegacyErrorBoundaryAsFailed_new,
   isAlreadyFailedLegacyErrorBoundary as isAlreadyFailedLegacyErrorBoundary_new,
   scheduleWork as scheduleWork_new,
-  requestWork as requestWork_new,
   flushRoot as flushRoot_new,
   batchedUpdates as batchedUpdates_new,
   unbatchedUpdates as unbatchedUpdates_new,
@@ -63,6 +62,7 @@ import {
   computeUniqueAsyncExpiration as computeUniqueAsyncExpiration_new,
   flushPassiveEffects as flushPassiveEffects_new,
   warnIfNotCurrentlyBatchingInDev as warnIfNotCurrentlyBatchingInDev_new,
+  inferStartTimeFromExpirationTime as inferStartTimeFromExpirationTime_new,
 } from './ReactFiberScheduler.new';
 
 export let requestCurrentTime = requestCurrentTime_old;
@@ -77,7 +77,6 @@ export let resolveRetryThenable = resolveRetryThenable_old;
 export let markLegacyErrorBoundaryAsFailed = markLegacyErrorBoundaryAsFailed_old;
 export let isAlreadyFailedLegacyErrorBoundary = isAlreadyFailedLegacyErrorBoundary_old;
 export let scheduleWork = scheduleWork_old;
-export let requestWork = requestWork_old;
 export let flushRoot = flushRoot_old;
 export let batchedUpdates = batchedUpdates_old;
 export let unbatchedUpdates = unbatchedUpdates_old;
@@ -90,6 +89,7 @@ export let flushInteractiveUpdates = flushInteractiveUpdates_old;
 export let computeUniqueAsyncExpiration = computeUniqueAsyncExpiration_old;
 export let flushPassiveEffects = flushPassiveEffects_old;
 export let warnIfNotCurrentlyBatchingInDev = warnIfNotCurrentlyBatchingInDev_old;
+export let inferStartTimeFromExpirationTime = inferStartTimeFromExpirationTime_old;
 
 if (enableNewScheduler) {
   requestCurrentTime = requestCurrentTime_new;
@@ -104,7 +104,6 @@ if (enableNewScheduler) {
   markLegacyErrorBoundaryAsFailed = markLegacyErrorBoundaryAsFailed_new;
   isAlreadyFailedLegacyErrorBoundary = isAlreadyFailedLegacyErrorBoundary_new;
   scheduleWork = scheduleWork_new;
-  requestWork = requestWork_new;
   flushRoot = flushRoot_new;
   batchedUpdates = batchedUpdates_new;
   unbatchedUpdates = unbatchedUpdates_new;
@@ -117,6 +116,7 @@ if (enableNewScheduler) {
   computeUniqueAsyncExpiration = computeUniqueAsyncExpiration_new;
   flushPassiveEffects = flushPassiveEffects_new;
   warnIfNotCurrentlyBatchingInDev = warnIfNotCurrentlyBatchingInDev_new;
+  inferStartTimeFromExpirationTime = inferStartTimeFromExpirationTime_new;
 }
 
 export type Thenable = {