Add alwaysThrottleRetries flag

packages/react-reconciler/src/ReactFiberWorkLoop.js

@@ -39,6 +39,7 @@ import {
   enableTransitionTracing,
   useModernStrictMode,
   disableLegacyContext,
+  alwaysThrottleRetries,
 } from 'shared/ReactFeatureFlags';
 import ReactSharedInternals from 'shared/ReactSharedInternals';
 import is from 'shared/objectIs';
@@ -1115,7 +1116,10 @@ function finishConcurrentRender(
       workInProgressTransitions,
     );
   } else {
-    if (includesOnlyRetries(lanes)) {
+    if (
+      includesOnlyRetries(lanes) &&
+      (alwaysThrottleRetries || exitStatus === RootSuspended)
+    ) {
       // This render only included retries, no updates. Throttle committing
       // retries so that we don't show too many loading states too quickly.
       const msUntilTimeout =

packages/react-reconciler/src/__tests__/ReactSuspenseWithNoopRenderer-test.js

@@ -1779,10 +1779,28 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       await resolveText('B');
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Loading..." />);
 
-      // Restart and render the complete content. The tree will finish but we
-      // won't commit the result yet because the fallback appeared recently.
+      // Restart and render the complete content.
       await waitForAll(['A', 'B']);
-      expect(ReactNoop).toMatchRenderedOutput(<span prop="Loading..." />);
+
+      if (gate(flags => flags.alwaysThrottleRetries)) {
+        // Correct behavior:
+        //
+        // The tree will finish but we won't commit the result yet because the fallback appeared recently.
+        expect(ReactNoop).toMatchRenderedOutput(<span prop="Loading..." />);
+      } else {
+        // Old behavior, gated until this rolls out at Meta:
+        //
+        // TODO: Because this render was the result of a retry, and a fallback
+        // was shown recently, we should suspend and remain on the fallback for
+        // little bit longer. We currently only do this if there's still
+        // remaining fallbacks in the tree, but we should do it for all retries.
+        expect(ReactNoop).toMatchRenderedOutput(
+          <>
+            <span prop="A" />
+            <span prop="B" />
+          </>,
+        );
+      }
     });
     assertLog([]);
     expect(ReactNoop).toMatchRenderedOutput(

packages/shared/ReactFeatureFlags.js

@@ -124,6 +124,8 @@ export const diffInCommitPhase = __EXPERIMENTAL__;
 
 export const enableAsyncActions = __EXPERIMENTAL__;
 
+export const alwaysThrottleRetries = true;
+
 // -----------------------------------------------------------------------------
 // Chopping Block
 //

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

@@ -22,6 +22,7 @@ import typeof * as DynamicFlagsType from 'ReactNativeInternalFeatureFlags';
 
 export const enableUseRefAccessWarning = __VARIANT__;
 export const enableDeferRootSchedulingToMicrotask = __VARIANT__;
+export const alwaysThrottleRetries = __VARIANT__;
 
 // Flow magic to verify the exports of this file match the original version.
 ((((null: any): ExportsType): DynamicFlagsType): ExportsType);

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

@@ -17,8 +17,11 @@ import * as dynamicFlags from 'ReactNativeInternalFeatureFlags';
 
 // We destructure each value before re-exporting to avoid a dynamic look-up on
 // the exports object every time a flag is read.
-export const {enableUseRefAccessWarning, enableDeferRootSchedulingToMicrotask} =
-  dynamicFlags;
+export const {
+  enableUseRefAccessWarning,
+  enableDeferRootSchedulingToMicrotask,
+  alwaysThrottleRetries,
+} = dynamicFlags;
 
 // The rest of the flags are static for better dead code elimination.
 export const enableDebugTracing = false;

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

@@ -75,5 +75,7 @@ export const enableDeferRootSchedulingToMicrotask = true;
 export const diffInCommitPhase = true;
 export const enableAsyncActions = false;
 
+export const alwaysThrottleRetries = true;
+
 // Flow magic to verify the exports of this file match the original version.
 ((((null: any): ExportsType): FeatureFlagsType): ExportsType);

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

@@ -75,5 +75,7 @@ export const enableDeferRootSchedulingToMicrotask = true;
 export const diffInCommitPhase = true;
 export const enableAsyncActions = false;
 
+export const alwaysThrottleRetries = true;
+
 // Flow magic to verify the exports of this file match the original version.
 ((((null: any): ExportsType): FeatureFlagsType): ExportsType);

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

@@ -72,5 +72,7 @@ export const enableDeferRootSchedulingToMicrotask = true;
 export const diffInCommitPhase = true;
 export const enableAsyncActions = false;
 
+export const alwaysThrottleRetries = true;
+
 // Flow magic to verify the exports of this file match the original version.
 ((((null: any): ExportsType): FeatureFlagsType): ExportsType);

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

@@ -77,5 +77,7 @@ export const enableDeferRootSchedulingToMicrotask = true;
 export const diffInCommitPhase = true;
 export const enableAsyncActions = false;
 
+export const alwaysThrottleRetries = true;
+
 // Flow magic to verify the exports of this file match the original version.
 ((((null: any): ExportsType): FeatureFlagsType): ExportsType);

packages/shared/forks/ReactFeatureFlags.www-dynamic.js

@@ -27,6 +27,7 @@ export const enableCustomElementPropertySupport = __VARIANT__;
 export const enableDeferRootSchedulingToMicrotask = __VARIANT__;
 export const diffInCommitPhase = __VARIANT__;
 export const enableAsyncActions = __VARIANT__;
+export const alwaysThrottleRetries = __VARIANT__;
 
 // Enable this flag to help with concurrent mode debugging.
 // It logs information to the console about React scheduling, rendering, and commit phases.

packages/shared/forks/ReactFeatureFlags.www.js

@@ -30,6 +30,7 @@ export const {
   enableDeferRootSchedulingToMicrotask,
   diffInCommitPhase,
   enableAsyncActions,
+  alwaysThrottleRetries,
 } = dynamicFeatureFlags;
 
 // On WWW, __EXPERIMENTAL__ is used for a new modern build.

scripts/flow/xplat.js

@@ -10,4 +10,5 @@
 declare module 'ReactNativeInternalFeatureFlags' {
   declare export var enableUseRefAccessWarning: boolean;
   declare export var enableDeferRootSchedulingToMicrotask: boolean;
+  declare export var alwaysThrottleRetries: boolean;
 }