Remove disableYielding feature flag (#15654)

Obviated by Batched Mode.

packages/react-dom/src/__tests__/ReactDOMFiberAsync-test.internal.js

@@ -10,7 +10,6 @@
 'use strict';
 
 const React = require('react');
-const Fragment = React.Fragment;
 let ReactFeatureFlags = require('shared/ReactFeatureFlags');
 
 let ReactDOM;
@@ -602,84 +601,4 @@ describe('ReactDOMFiberAsync', () => {
       expect(root.createBatch).toBe(undefined);
     });
   });
-
-  describe('Disable yielding', () => {
-    beforeEach(() => {
-      jest.resetModules();
-      ReactFeatureFlags = require('shared/ReactFeatureFlags');
-      ReactFeatureFlags.disableYielding = true;
-      ReactFeatureFlags.debugRenderPhaseSideEffectsForStrictMode = false;
-      ReactDOM = require('react-dom');
-      Scheduler = require('scheduler');
-    });
-
-    it('wont yield during a render if yielding is disabled', () => {
-      class A extends React.Component {
-        render() {
-          Scheduler.yieldValue('A');
-          return <div>{this.props.children}</div>;
-        }
-      }
-
-      class B extends React.Component {
-        render() {
-          Scheduler.yieldValue('B');
-          return <div>{this.props.children}</div>;
-        }
-      }
-
-      class C extends React.Component {
-        render() {
-          Scheduler.yieldValue('C');
-          return <div>{this.props.children}</div>;
-        }
-      }
-
-      let root = ReactDOM.unstable_createRoot(container);
-
-      root.render(
-        <Fragment>
-          <A />
-          <B />
-          <C />
-        </Fragment>,
-      );
-
-      expect(Scheduler).toHaveYielded([]);
-
-      Scheduler.unstable_flushNumberOfYields(2);
-      // Even though we just flushed two yields, we should have rendered
-      // everything without yielding when the flag is on.
-      expect(Scheduler).toHaveYielded(['A', 'B', 'C']);
-    });
-
-    it('wont suspend during a render if yielding is disabled', () => {
-      let p = new Promise(resolve => {});
-
-      function Suspend() {
-        throw p;
-      }
-
-      let root = ReactDOM.unstable_createRoot(container);
-      root.render(
-        <React.Suspense fallback={'Loading'}>Initial</React.Suspense>,
-      );
-
-      Scheduler.flushAll();
-      expect(container.textContent).toBe('Initial');
-
-      root.render(
-        <React.Suspense fallback={'Loading'}>
-          <Suspend />
-        </React.Suspense>,
-      );
-
-      expect(Scheduler).toHaveYielded([]);
-
-      Scheduler.flushAll();
-
-      // This should have flushed to the DOM even though we haven't ran the timers.
-      expect(container.textContent).toBe('Loading');
-    });
-  });
 });

packages/react-reconciler/src/ReactFiberWorkLoop.js

@@ -23,7 +23,6 @@ import {
   enableSuspenseServerRenderer,
   replayFailedUnitOfWorkWithInvokeGuardedCallback,
   enableProfilerTimer,
-  disableYielding,
   enableSchedulerTracing,
   revertPassiveEffectsChange,
 } from 'shared/ReactFeatureFlags';
@@ -1004,7 +1003,7 @@ function renderRoot(
       // possible.
       const hasNotProcessedNewUpdates =
         workInProgressRootLatestProcessedExpirationTime === Sync;
-      if (hasNotProcessedNewUpdates && !disableYielding && !isSync) {
+      if (hasNotProcessedNewUpdates && !isSync) {
         // If we have not processed any new updates during this pass, then this is
         // either a retry of an existing fallback state or a hidden tree.
         // Hidden trees shouldn't be batched with other work and after that's
@@ -1041,7 +1040,7 @@ function renderRoot(
       return commitRoot.bind(null, root);
     }
     case RootSuspendedWithDelay: {
-      if (!disableYielding && !isSync) {
+      if (!isSync) {
         // We're suspended in a state that should be avoided. We'll try to avoid committing
         // it for as long as the timeouts let us.
         if (workInProgressRootHasPendingPing) {
@@ -2147,11 +2146,6 @@ function computeMsUntilSuspenseLoadingDelay(
   committedExpirationTime: ExpirationTime,
   suspenseConfig: SuspenseConfig,
 ) {
-  if (disableYielding) {
-    // Timeout immediately when yielding is disabled.
-    return 0;
-  }
-
   const busyMinDurationMs = (suspenseConfig.busyMinDurationMs: any) | 0;
   if (busyMinDurationMs <= 0) {
     return 0;

packages/react-reconciler/src/SchedulerWithReactIntegration.js

@@ -11,10 +11,7 @@
 // CommonJS interop named imports.
 import * as Scheduler from 'scheduler';
 import {__interactionsRef} from 'scheduler/tracing';
-import {
-  disableYielding,
-  enableSchedulerTracing,
-} from 'shared/ReactFeatureFlags';
+import {enableSchedulerTracing} from 'shared/ReactFeatureFlags';
 import invariant from 'shared/invariant';
 
 const {
@@ -65,9 +62,7 @@ export const IdlePriority: ReactPriorityLevel = 95;
 // NoPriority is the absence of priority. Also React-only.
 export const NoPriority: ReactPriorityLevel = 90;
 
-export const shouldYield = disableYielding
-  ? () => false // Never yield when `disableYielding` is on
-  : Scheduler_shouldYield;
+export const shouldYield = Scheduler_shouldYield;
 
 let syncQueue: Array<SchedulerCallback> | null = null;
 let immediateQueueCallbackNode: mixed | null = null;

packages/shared/ReactFeatureFlags.js

@@ -45,9 +45,6 @@ export function addUserTimingListener() {
 // Disable javascript: URL strings in href for XSS protection.
 export const disableJavaScriptURLs = false;
 
-// Disables yielding during render in Concurrent Mode. Used for debugging only.
-export const disableYielding = false;
-
 // React Fire: prevent the value and checked attributes from syncing
 // with their related DOM properties
 export const disableInputAttributeSyncing = false;

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

@@ -27,7 +27,6 @@ export const warnAboutShorthandPropertyCollision = false;
 export const enableSchedulerDebugging = false;
 export const debugRenderPhaseSideEffectsForStrictMode = true;
 export const disableJavaScriptURLs = false;
-export const disableYielding = false;
 export const disableInputAttributeSyncing = false;
 export const replayFailedUnitOfWorkWithInvokeGuardedCallback = __DEV__;
 export const warnAboutDeprecatedLifecycles = true;

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

@@ -21,7 +21,6 @@ export const enableProfilerTimer = __PROFILE__;
 export const enableSchedulerTracing = __PROFILE__;
 export const enableSuspenseServerRenderer = false;
 export const disableJavaScriptURLs = false;
-export const disableYielding = false;
 export const disableInputAttributeSyncing = false;
 export const enableStableConcurrentModeAPIs = false;
 export const warnAboutShorthandPropertyCollision = false;

packages/shared/forks/ReactFeatureFlags.persistent.js

@@ -21,7 +21,6 @@ export const enableProfilerTimer = __PROFILE__;
 export const enableSchedulerTracing = __PROFILE__;
 export const enableSuspenseServerRenderer = false;
 export const disableJavaScriptURLs = false;
-export const disableYielding = false;
 export const disableInputAttributeSyncing = false;
 export const enableStableConcurrentModeAPIs = false;
 export const warnAboutShorthandPropertyCollision = false;

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

@@ -21,7 +21,6 @@ export const enableProfilerTimer = false;
 export const enableSchedulerTracing = false;
 export const enableSuspenseServerRenderer = false;
 export const disableJavaScriptURLs = false;
-export const disableYielding = false;
 export const disableInputAttributeSyncing = false;
 export const enableStableConcurrentModeAPIs = false;
 export const warnAboutShorthandPropertyCollision = false;

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

@@ -27,7 +27,6 @@ export const enableStableConcurrentModeAPIs = false;
 export const enableSchedulerDebugging = false;
 export const warnAboutDeprecatedSetNativeProps = false;
 export const disableJavaScriptURLs = false;
-export const disableYielding = false;
 export const enableEventAPI = true;
 export const enableJSXTransformAPI = true;
 export const warnAboutMissingMockScheduler = true;

packages/shared/forks/ReactFeatureFlags.www.js

@@ -16,7 +16,6 @@ export const {
   debugRenderPhaseSideEffectsForStrictMode,
   replayFailedUnitOfWorkWithInvokeGuardedCallback,
   warnAboutDeprecatedLifecycles,
-  disableYielding,
   disableInputAttributeSyncing,
   warnAboutShorthandPropertyCollision,
   warnAboutDeprecatedSetNativeProps,