[flags] Delete enableSuspenseAvoidThisFallbackFizz (#31779)

We're not shipping `enableSuspenseAvoidThisFallback` and the fizz flag
is already off so we can delete it.

Author: rickhanlonii

packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js

@@ -3886,18 +3886,6 @@ const clientRenderedSuspenseBoundaryError1D =
 const clientRenderedSuspenseBoundaryError2 =
   stringToPrecomputedChunk('></template>');
 
-export function pushStartCompletedSuspenseBoundary(
-  target: Array<Chunk | PrecomputedChunk>,
-) {
-  target.push(startCompletedSuspenseBoundary);
-}
-
-export function pushEndCompletedSuspenseBoundary(
-  target: Array<Chunk | PrecomputedChunk>,
-) {
-  target.push(endSuspenseBoundary);
-}
-
 export function writeStartCompletedSuspenseBoundary(
   destination: Destination,
   renderState: RenderState,

packages/react-dom-bindings/src/server/ReactFizzConfigDOMLegacy.js

@@ -142,8 +142,6 @@ export {
   makeId,
   pushStartInstance,
   pushEndInstance,
-  pushStartCompletedSuspenseBoundary,
-  pushEndCompletedSuspenseBoundary,
   pushFormStateMarkerIsMatching,
   pushFormStateMarkerIsNotMatching,
   writeStartSegment,

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

@@ -2211,151 +2211,6 @@ describe('ReactDOMFizzServer', () => {
     expect(getVisibleChildren(container)).toEqual(<div>Hello</div>);
   });
 
-  // @gate enableSuspenseAvoidThisFallbackFizz
-  it('should respect unstable_avoidThisFallback', async () => {
-    const resolved = {
-      0: false,
-      1: false,
-    };
-    const promiseRes = {};
-    const promises = {
-      0: new Promise(res => {
-        promiseRes[0] = () => {
-          resolved[0] = true;
-          res();
-        };
-      }),
-      1: new Promise(res => {
-        promiseRes[1] = () => {
-          resolved[1] = true;
-          res();
-        };
-      }),
-    };
-
-    const InnerComponent = ({isClient, depth}) => {
-      if (isClient) {
-        // Resuspend after re-rendering on client to check that fallback shows on client
-        throw new Promise(() => {});
-      }
-      if (!resolved[depth]) {
-        throw promises[depth];
-      }
-      return (
-        <div>
-          <Text text={`resolved ${depth}`} />
-        </div>
-      );
-    };
-
-    function App({isClient}) {
-      return (
-        <div>
-          <Text text="Non Suspense Content" />
-          <Suspense
-            fallback={
-              <span>
-                <Text text="Avoided Fallback" />
-              </span>
-            }
-            unstable_avoidThisFallback={true}>
-            <InnerComponent isClient={isClient} depth={0} />
-            <div>
-              <Suspense fallback={<Text text="Fallback" />}>
-                <Suspense
-                  fallback={
-                    <span>
-                      <Text text="Avoided Fallback2" />
-                    </span>
-                  }
-                  unstable_avoidThisFallback={true}>
-                  <InnerComponent isClient={isClient} depth={1} />
-                </Suspense>
-              </Suspense>
-            </div>
-          </Suspense>
-        </div>
-      );
-    }
-
-    await jest.runAllTimers();
-
-    await act(() => {
-      const {pipe} = renderToPipeableStream(<App isClient={false} />);
-      pipe(writable);
-    });
-
-    // Nothing is output since root has a suspense with avoidedThisFallback that hasn't resolved
-    expect(getVisibleChildren(container)).toEqual(undefined);
-    expect(container.innerHTML).not.toContain('Avoided Fallback');
-
-    // resolve first suspense component with avoidThisFallback
-    await act(() => {
-      promiseRes[0]();
-    });
-
-    expect(getVisibleChildren(container)).toEqual(
-      <div>
-        Non Suspense Content
-        <div>resolved 0</div>
-        <div>Fallback</div>
-      </div>,
-    );
-
-    expect(container.innerHTML).not.toContain('Avoided Fallback2');
-
-    await act(() => {
-      promiseRes[1]();
-    });
-
-    expect(getVisibleChildren(container)).toEqual(
-      <div>
-        Non Suspense Content
-        <div>resolved 0</div>
-        <div>
-          <div>resolved 1</div>
-        </div>
-      </div>,
-    );
-
-    let root;
-    await act(async () => {
-      root = ReactDOMClient.hydrateRoot(container, <App isClient={false} />);
-      await waitForAll([]);
-      await jest.runAllTimers();
-    });
-
-    // No change after hydration
-    expect(getVisibleChildren(container)).toEqual(
-      <div>
-        Non Suspense Content
-        <div>resolved 0</div>
-        <div>
-          <div>resolved 1</div>
-        </div>
-      </div>,
-    );
-
-    await act(async () => {
-      // Trigger update by changing isClient to true
-      root.render(<App isClient={true} />);
-      await waitForAll([]);
-      await jest.runAllTimers();
-    });
-
-    // Now that we've resuspended at the root we show the root fallback
-    expect(getVisibleChildren(container)).toEqual(
-      <div>
-        Non Suspense Content
-        <div style="display: none;">resolved 0</div>
-        <div style="display: none;">
-          <div>resolved 1</div>
-        </div>
-        <span>Avoided Fallback</span>
-      </div>,
-    );
-  });
-
   it('calls getServerSnapshot instead of getSnapshot', async () => {
     const ref = React.createRef();
 

packages/react-markup/src/ReactFizzConfigMarkup.js

@@ -49,8 +49,6 @@ export {
   getChildFormatContext,
   makeId,
   pushEndInstance,
-  pushStartCompletedSuspenseBoundary,
-  pushEndCompletedSuspenseBoundary,
   pushFormStateMarkerIsMatching,
   pushFormStateMarkerIsNotMatching,
   writeStartSegment,

packages/react-server/src/ReactFizzServer.js

@@ -65,8 +65,6 @@ import {
   pushTextInstance,
   pushStartInstance,
   pushEndInstance,
-  pushStartCompletedSuspenseBoundary,
-  pushEndCompletedSuspenseBoundary,
   pushSegmentFinale,
   getChildFormatContext,
   writeHoistables,
@@ -155,7 +153,6 @@ import {
   disableLegacyContext,
   disableLegacyContextForFunctionComponents,
   enableScopeAPI,
-  enableSuspenseAvoidThisFallbackFizz,
   enableCache,
   enablePostpone,
   enableHalt,
@@ -1490,28 +1487,6 @@ function replaySuspenseBoundary(
   request.pingedTasks.push(suspendedFallbackTask);
 }
 
-function renderBackupSuspenseBoundary(
-  request: Request,
-  task: Task,
-  keyPath: KeyNode,
-  props: Object,
-) {
-  const content = props.children;
-  const segment = task.blockedSegment;
-  const prevKeyPath = task.keyPath;
-  task.keyPath = keyPath;
-  if (segment === null) {
-    // Replay
-    renderNode(request, task, content, -1);
-  } else {
-    // Render
-    pushStartCompletedSuspenseBoundary(segment.chunks);
-    renderNode(request, task, content, -1);
-    pushEndCompletedSuspenseBoundary(segment.chunks);
-  }
-  task.keyPath = prevKeyPath;
-}
-
 function renderHostElement(
   request: Request,
   task: Task,
@@ -2194,14 +2169,7 @@ function renderElement(
       throw new Error('ReactDOMServer does not yet support scope components.');
     }
     case REACT_SUSPENSE_TYPE: {
-      if (
-        enableSuspenseAvoidThisFallbackFizz &&
-        props.unstable_avoidThisFallback === true
-      ) {
-        renderBackupSuspenseBoundary(request, task, keyPath, props);
-      } else {
-        renderSuspenseBoundary(request, task, keyPath, props);
-      }
+      renderSuspenseBoundary(request, task, keyPath, props);
       return;
     }
   }

packages/react-server/src/forks/ReactFizzConfig.custom.js

@@ -51,10 +51,6 @@ export const makeId = $$$config.makeId;
 export const pushTextInstance = $$$config.pushTextInstance;
 export const pushStartInstance = $$$config.pushStartInstance;
 export const pushEndInstance = $$$config.pushEndInstance;
-export const pushStartCompletedSuspenseBoundary =
-  $$$config.pushStartCompletedSuspenseBoundary;
-export const pushEndCompletedSuspenseBoundary =
-  $$$config.pushEndCompletedSuspenseBoundary;
 export const pushSegmentFinale = $$$config.pushSegmentFinale;
 export const pushFormStateMarkerIsMatching =
   $$$config.pushFormStateMarkerIsMatching;

packages/shared/ReactFeatureFlags.js

@@ -108,8 +108,6 @@ export const enableLegacyHidden = false;
 
 // Enables unstable_avoidThisFallback feature in Fiber
 export const enableSuspenseAvoidThisFallback = false;
-// Enables unstable_avoidThisFallback feature in Fizz
-export const enableSuspenseAvoidThisFallbackFizz = false;
 
 export const enableCPUSuspense = __EXPERIMENTAL__;
 

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

@@ -73,7 +73,6 @@ export const enableComponentPerformanceTrack = false;
 export const enableScopeAPI = false;
 export const enableServerComponentLogs = true;
 export const enableSuspenseAvoidThisFallback = false;
-export const enableSuspenseAvoidThisFallbackFizz = false;
 export const enableSuspenseCallback = true;
 export const enableTaint = true;
 export const enableTransitionTracing = false;

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

@@ -63,7 +63,6 @@ export const enableScopeAPI = false;
 export const enableServerComponentLogs = true;
 export const enableShallowPropDiffing = false;
 export const enableSuspenseAvoidThisFallback = false;
-export const enableSuspenseAvoidThisFallbackFizz = false;
 export const enableSuspenseCallback = false;
 export const enableTaint = true;
 export const enableTransitionTracing = false;

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

@@ -33,7 +33,6 @@ export const enableSuspenseCallback = false;
 export const enableTrustedTypesIntegration = false;
 export const disableTextareaChildren = false;
 export const enableSuspenseAvoidThisFallback = false;
-export const enableSuspenseAvoidThisFallbackFizz = false;
 export const enableCPUSuspense = false;
 export const enableNoCloningMemoCache = false;
 export const enableUseEffectEventHook = false;