Add feature flags for expiration times (#27821)

It seems worthwhile to me to run a test to experiment with different
expiration times. This moves the expiration times for scheduler and
reconciler into FeatureFlags for the facebook build. Non-facebook should
not be affected by these changes.

Author: kassens

packages/react-reconciler/src/ReactFiberLane.js

@@ -25,6 +25,9 @@ import {
   enableTransitionTracing,
   enableUnifiedSyncLane,
   enableUpdaterTracking,
+  syncLaneExpirationMs,
+  transitionLaneExpirationMs,
+  retryLaneExpirationMs,
 } from 'shared/ReactFeatureFlags';
 import {isDevToolsPresent} from './ReactFiberDevToolsHook';
 import {ConcurrentUpdatesByDefaultMode, NoMode} from './ReactTypeOfMode';
@@ -355,7 +358,7 @@ function computeExpirationTime(lane: Lane, currentTime: number) {
       // to fix the starvation. However, this scenario supports the idea that
       // expiration times are an important safeguard when starvation
       // does happen.
-      return currentTime + 250;
+      return currentTime + syncLaneExpirationMs;
     case DefaultHydrationLane:
     case DefaultLane:
     case TransitionHydrationLane:
@@ -374,7 +377,7 @@ function computeExpirationTime(lane: Lane, currentTime: number) {
     case TransitionLane13:
     case TransitionLane14:
     case TransitionLane15:
-      return currentTime + 5000;
+      return currentTime + transitionLaneExpirationMs;
     case RetryLane1:
     case RetryLane2:
     case RetryLane3:
@@ -384,7 +387,9 @@ function computeExpirationTime(lane: Lane, currentTime: number) {
       // crashes. There must be some other underlying bug; not super urgent but
       // ideally should figure out why and fix it. Unfortunately we don't have
       // a repro for the crashes, only detected via production metrics.
-      return enableRetryLaneExpiration ? currentTime + 5000 : NoTimestamp;
+      return enableRetryLaneExpiration
+        ? currentTime + retryLaneExpirationMs
+        : NoTimestamp;
     case SelectiveHydrationLane:
     case IdleHydrationLane:
     case IdleLane:

packages/scheduler/src/SchedulerFeatureFlags.js

@@ -14,3 +14,7 @@ export const enableIsInputPendingContinuous = false;
 export const frameYieldMs = 5;
 export const continuousYieldMs = 50;
 export const maxYieldMs = 300;
+
+export const userBlockingPriorityTimeout = 250;
+export const normalPriorityTimeout = 5000;
+export const lowPriorityTimeout = 10000;

packages/scheduler/src/forks/Scheduler.js

@@ -19,6 +19,9 @@ import {
   frameYieldMs,
   continuousYieldMs,
   maxYieldMs,
+  userBlockingPriorityTimeout,
+  lowPriorityTimeout,
+  normalPriorityTimeout,
 } from '../SchedulerFeatureFlags';
 
 import {push, pop, peek} from '../SchedulerMinHeap';
@@ -75,15 +78,6 @@ if (hasPerformanceNow) {
 // 0b111111111111111111111111111111
 var maxSigned31BitInt = 1073741823;
 
-// Times out immediately
-var IMMEDIATE_PRIORITY_TIMEOUT = -1;
-// Eventually times out
-var USER_BLOCKING_PRIORITY_TIMEOUT = 250;
-var NORMAL_PRIORITY_TIMEOUT = 5000;
-var LOW_PRIORITY_TIMEOUT = 10000;
-// Never times out
-var IDLE_PRIORITY_TIMEOUT = maxSigned31BitInt;
-
 // Tasks are stored on a min heap
 var taskQueue: Array<Task> = [];
 var timerQueue: Array<Task> = [];
@@ -362,20 +356,25 @@ function unstable_scheduleCallback(
   var timeout;
   switch (priorityLevel) {
     case ImmediatePriority:
-      timeout = IMMEDIATE_PRIORITY_TIMEOUT;
+      // Times out immediately
+      timeout = -1;
       break;
     case UserBlockingPriority:
-      timeout = USER_BLOCKING_PRIORITY_TIMEOUT;
+      // Eventually times out
+      timeout = userBlockingPriorityTimeout;
       break;
     case IdlePriority:
-      timeout = IDLE_PRIORITY_TIMEOUT;
+      // Never times out
+      timeout = maxSigned31BitInt;
       break;
     case LowPriority:
-      timeout = LOW_PRIORITY_TIMEOUT;
+      // Eventually times out
+      timeout = lowPriorityTimeout;
       break;
     case NormalPriority:
     default:
-      timeout = NORMAL_PRIORITY_TIMEOUT;
+      // Eventually times out
+      timeout = normalPriorityTimeout;
       break;
   }
 

packages/scheduler/src/forks/SchedulerFeatureFlags.www-dynamic.js

@@ -12,3 +12,7 @@
 // with the __VARIANT__ set to `true`, and once set to `false`.
 
 export const enableProfiling = __VARIANT__;
+
+export const userBlockingPriorityTimeout = 250;
+export const normalPriorityTimeout = 5000;
+export const lowPriorityTimeout = 10000;

packages/scheduler/src/forks/SchedulerFeatureFlags.www.js

@@ -7,10 +7,16 @@
  * @flow
  */
 
-const {enableProfiling: enableProfilingFeatureFlag} =
-  // $FlowFixMe[cannot-resolve-module]
-  require('SchedulerFeatureFlags');
+// $FlowFixMe[cannot-resolve-module]
+const dynamicFeatureFlags = require('SchedulerFeatureFlags');
 
+const {enableProfiling: enableProfilingFeatureFlag} = dynamicFeatureFlags;
+
+export const {
+  userBlockingPriorityTimeout,
+  normalPriorityTimeout,
+  lowPriorityTimeout,
+} = dynamicFeatureFlags;
 export const enableSchedulerDebugging = true;
 export const enableProfiling: boolean =
   __PROFILE__ && enableProfilingFeatureFlag;

packages/shared/ReactFeatureFlags.js

@@ -130,6 +130,9 @@ export const enableUseDeferredValueInitialArg = __EXPERIMENTAL__;
  * Enables an expiration time for retry lanes to avoid starvation.
  */
 export const enableRetryLaneExpiration = false;
+export const retryLaneExpirationMs = 5000;
+export const syncLaneExpirationMs = 250;
+export const transitionLaneExpirationMs = 5000;
 
 // -----------------------------------------------------------------------------
 // Chopping Block

packages/shared/forks/ReactFeatureFlags.native-fb.js

@@ -66,7 +66,11 @@ export const enableComponentStackLocations = false;
 export const enableLegacyFBSupport = false;
 export const enableFilterEmptyStringAttributesDOM = false;
 export const enableGetInspectorDataForInstanceInProduction = true;
+
 export const enableRetryLaneExpiration = false;
+export const retryLaneExpirationMs = 5000;
+export const syncLaneExpirationMs = 250;
+export const transitionLaneExpirationMs = 5000;
 
 export const createRootStrictEffectsByDefault = false;
 

packages/shared/forks/ReactFeatureFlags.native-oss.js

@@ -49,7 +49,11 @@ export const enableComponentStackLocations = false;
 export const enableLegacyFBSupport = false;
 export const enableFilterEmptyStringAttributesDOM = false;
 export const enableGetInspectorDataForInstanceInProduction = false;
+
 export const enableRetryLaneExpiration = false;
+export const retryLaneExpirationMs = 5000;
+export const syncLaneExpirationMs = 250;
+export const transitionLaneExpirationMs = 5000;
 
 export const createRootStrictEffectsByDefault = false;
 export const enableUseRefAccessWarning = false;

packages/shared/forks/ReactFeatureFlags.test-renderer.js

@@ -49,7 +49,11 @@ export const enableComponentStackLocations = true;
 export const enableLegacyFBSupport = false;
 export const enableFilterEmptyStringAttributesDOM = false;
 export const enableGetInspectorDataForInstanceInProduction = false;
+
 export const enableRetryLaneExpiration = false;
+export const retryLaneExpirationMs = 5000;
+export const syncLaneExpirationMs = 250;
+export const transitionLaneExpirationMs = 5000;
 
 export const createRootStrictEffectsByDefault = false;
 export const enableUseRefAccessWarning = false;

packages/shared/forks/ReactFeatureFlags.test-renderer.native.js

@@ -51,7 +51,11 @@ export const enableUseEffectEventHook = false;
 export const enableClientRenderFallbackOnTextMismatch = true;
 export const createRootStrictEffectsByDefault = false;
 export const enableUseRefAccessWarning = false;
+
 export const enableRetryLaneExpiration = false;
+export const retryLaneExpirationMs = 5000;
+export const syncLaneExpirationMs = 250;
+export const transitionLaneExpirationMs = 5000;
 
 export const disableSchedulerTimeoutInWorkLoop = false;
 export const enableLazyContextPropagation = false;