Read current time without marking event start time

`requestCurrentTime` is only meant to be used for updates, because
subsequent calls within the same event will receive the same time.
Messing this up has bad consequences.

I renamed it to `requestCurrentTimeForUpdate` and created a new
function that returns the current time without the batching heuristic,
called `getCurrentTime`.

Swapping `requestCurrentTime` for `getCurrentTime` in the DevTools
hook fixes the regression test added in the previous commit.

Author: acdlite

packages/react-reconciler/src/ReactFiberBeginWork.js

@@ -173,7 +173,7 @@ import {
 } from './ReactFiber';
 import {
   markSpawnedWork,
-  requestCurrentTime,
+  requestCurrentTimeForUpdate,
   retryDehydratedSuspenseBoundary,
   scheduleWork,
   renderDidSuspendDelayIfPossible,
@@ -1990,7 +1990,7 @@ function mountDehydratedSuspenseComponent(
     // a protocol to transfer that time, we'll just estimate it by using the current
     // time. This will mean that Suspense timeouts are slightly shifted to later than
     // they should be.
-    let serverDisplayTime = requestCurrentTime();
+    let serverDisplayTime = requestCurrentTimeForUpdate();
     // Schedule a normal pri update to render this content.
     let newExpirationTime = computeAsyncExpiration(serverDisplayTime);
     if (enableSchedulerTracing) {

packages/react-reconciler/src/ReactFiberClassComponent.js

@@ -50,7 +50,7 @@ import {
 } from './ReactFiberContext';
 import {readContext} from './ReactFiberNewContext';
 import {
-  requestCurrentTime,
+  requestCurrentTimeForUpdate,
   computeExpirationForFiber,
   scheduleWork,
 } from './ReactFiberWorkLoop';
@@ -183,7 +183,7 @@ const classComponentUpdater = {
   isMounted,
   enqueueSetState(inst, payload, callback) {
     const fiber = getInstance(inst);
-    const currentTime = requestCurrentTime();
+    const currentTime = requestCurrentTimeForUpdate();
     const suspenseConfig = requestCurrentSuspenseConfig();
     const expirationTime = computeExpirationForFiber(
       currentTime,
@@ -205,7 +205,7 @@ const classComponentUpdater = {
   },
   enqueueReplaceState(inst, payload, callback) {
     const fiber = getInstance(inst);
-    const currentTime = requestCurrentTime();
+    const currentTime = requestCurrentTimeForUpdate();
     const suspenseConfig = requestCurrentSuspenseConfig();
     const expirationTime = computeExpirationForFiber(
       currentTime,
@@ -229,7 +229,7 @@ const classComponentUpdater = {
   },
   enqueueForceUpdate(inst, callback) {
     const fiber = getInstance(inst);
-    const currentTime = requestCurrentTime();
+    const currentTime = requestCurrentTimeForUpdate();
     const suspenseConfig = requestCurrentSuspenseConfig();
     const expirationTime = computeExpirationForFiber(
       currentTime,

packages/react-reconciler/src/ReactFiberDevToolsHook.js

@@ -8,7 +8,7 @@
  */
 
 import {enableProfilerTimer} from 'shared/ReactFeatureFlags';
-import {requestCurrentTime} from './ReactFiberWorkLoop';
+import {getCurrentTime} from './ReactFiberWorkLoop';
 import {inferPriorityFromExpirationTime} from './ReactFiberExpirationTime';
 
 import type {Fiber} from './ReactFiber';
@@ -58,7 +58,7 @@ export function injectInternals(internals: Object): boolean {
       try {
         const didError = (root.current.effectTag & DidCapture) === DidCapture;
         if (enableProfilerTimer) {
-          const currentTime = requestCurrentTime();
+          const currentTime = getCurrentTime();
           const priorityLevel = inferPriorityFromExpirationTime(
             currentTime,
             expirationTime,

packages/react-reconciler/src/ReactFiberHooks.js

@@ -39,7 +39,7 @@ import {
 import {
   scheduleWork,
   computeExpirationForFiber,
-  requestCurrentTime,
+  requestCurrentTimeForUpdate,
   warnIfNotCurrentlyActingEffectsInDEV,
   warnIfNotCurrentlyActingUpdatesInDev,
   warnIfNotScopedWithMatchingAct,
@@ -1273,7 +1273,7 @@ function dispatchAction<S, A>(
       lastRenderPhaseUpdate.next = update;
     }
   } else {
-    const currentTime = requestCurrentTime();
+    const currentTime = requestCurrentTimeForUpdate();
     const suspenseConfig = requestCurrentSuspenseConfig();
     const expirationTime = computeExpirationForFiber(
       currentTime,

packages/react-reconciler/src/ReactFiberReconciler.js

@@ -50,7 +50,7 @@ import {
 import {createFiberRoot} from './ReactFiberRoot';
 import {injectInternals} from './ReactFiberDevToolsHook';
 import {
-  requestCurrentTime,
+  requestCurrentTimeForUpdate,
   computeExpirationForFiber,
   scheduleWork,
   flushRoot,
@@ -231,7 +231,7 @@ export function updateContainer(
   callback: ?Function,
 ): ExpirationTime {
   const current = container.current;
-  const currentTime = requestCurrentTime();
+  const currentTime = requestCurrentTimeForUpdate();
   if (__DEV__) {
     // $FlowExpectedError - jest isn't a global, and isn't recognized outside of tests
     if ('undefined' !== typeof jest) {
@@ -348,7 +348,9 @@ export function attemptSynchronousHydration(fiber: Fiber): void {
       // If we're still blocked after this, we need to increase
       // the priority of any promises resolving within this
       // boundary so that they next attempt also has higher pri.
-      let retryExpTime = computeInteractiveExpiration(requestCurrentTime());
+      let retryExpTime = computeInteractiveExpiration(
+        requestCurrentTimeForUpdate(),
+      );
       markRetryTimeIfNotHydrated(fiber, retryExpTime);
       break;
   }
@@ -380,7 +382,7 @@ export function attemptUserBlockingHydration(fiber: Fiber): void {
     // Suspense.
     return;
   }
-  let expTime = computeInteractiveExpiration(requestCurrentTime());
+  let expTime = computeInteractiveExpiration(requestCurrentTimeForUpdate());
   scheduleWork(fiber, expTime);
   markRetryTimeIfNotHydrated(fiber, expTime);
 }
@@ -393,7 +395,9 @@ export function attemptContinuousHydration(fiber: Fiber): void {
     // Suspense.
     return;
   }
-  let expTime = computeContinuousHydrationExpiration(requestCurrentTime());
+  let expTime = computeContinuousHydrationExpiration(
+    requestCurrentTimeForUpdate(),
+  );
   scheduleWork(fiber, expTime);
   markRetryTimeIfNotHydrated(fiber, expTime);
 }
@@ -404,7 +408,7 @@ export function attemptHydrationAtCurrentPriority(fiber: Fiber): void {
     // their priority other than synchronously flush it.
     return;
   }
-  const currentTime = requestCurrentTime();
+  const currentTime = requestCurrentTimeForUpdate();
   const expTime = computeExpirationForFiber(currentTime, fiber, null);
   scheduleWork(fiber, expTime);
   markRetryTimeIfNotHydrated(fiber, expTime);

packages/react-reconciler/src/ReactFiberWorkLoop.js

@@ -288,7 +288,7 @@ let spawnedWorkDuringRender: null | Array<ExpirationTime> = null;
 // receive the same expiration time. Otherwise we get tearing.
 let currentEventTime: ExpirationTime = NoWork;
 
-export function requestCurrentTime() {
+export function requestCurrentTimeForUpdate() {
   if ((executionContext & (RenderContext | CommitContext)) !== NoContext) {
     // We're inside React, so it's fine to read the actual time.
     return msToExpirationTime(now());
@@ -303,6 +303,10 @@ export function requestCurrentTime() {
   return currentEventTime;
 }
 
+export function getCurrentTime() {
+  return msToExpirationTime(now());
+}
+
 export function computeExpirationForFiber(
   currentTime: ExpirationTime,
   fiber: Fiber,
@@ -571,7 +575,7 @@ function ensureRootIsScheduled(root: FiberRoot) {
 
   // TODO: If this is an update, we already read the current time. Pass the
   // time as an argument.
-  const currentTime = requestCurrentTime();
+  const currentTime = requestCurrentTimeForUpdate();
   const priorityLevel = inferPriorityFromExpirationTime(
     currentTime,
     expirationTime,
@@ -632,7 +636,7 @@ function performConcurrentWorkOnRoot(root, didTimeout) {
   if (didTimeout) {
     // The render task took too long to complete. Mark the current time as
     // expired to synchronously render all expired work in a single batch.
-    const currentTime = requestCurrentTime();
+    const currentTime = requestCurrentTimeForUpdate();
     markRootExpiredAtTime(root, currentTime);
     // This will schedule a synchronous callback.
     ensureRootIsScheduled(root);
@@ -2380,7 +2384,7 @@ function retryTimedOutBoundary(
   // likely unblocked. Try rendering again, at a new expiration time.
   if (retryTime === NoWork) {
     const suspenseConfig = null; // Retries don't carry over the already committed update.
-    const currentTime = requestCurrentTime();
+    const currentTime = requestCurrentTimeForUpdate();
     retryTime = computeExpirationForFiber(
       currentTime,
       boundaryFiber,