Revert "Land enableClientRenderFallbackOnTextMismatch" (#24738)

This reverts commit 327e4a1.

Turns out we hadn't rolled this out internally yet — I mistook
enableClientRenderFallbackOnHydrationMismatch for
said enableClientRenderFallbackOnTextMismatch. Need to revert
until we finish rolling out the change.

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

@@ -3497,6 +3497,7 @@ describe('ReactDOMFizzServer', () => {
     );
   });
 
+  // @gate enableClientRenderFallbackOnTextMismatch
   it('#24384: Suspending should halt hydration warnings but still emit hydration warnings after unsuspending if mismatches are genuine', async () => {
     const makeApp = () => {
       let resolve, resolved;
@@ -3586,6 +3587,7 @@ describe('ReactDOMFizzServer', () => {
     expect(Scheduler).toFlushAndYield([]);
   });
 
+  // @gate enableClientRenderFallbackOnTextMismatch
   it('only warns once on hydration mismatch while within a suspense boundary', async () => {
     const originalConsoleError = console.error;
     const mockError = jest.fn();
@@ -4661,11 +4663,15 @@ describe('ReactDOMFizzServer', () => {
           },
         });
         expect(Scheduler).toFlushAndYield([]);
-        expect(errors).toEqual([
-          'Text content does not match server-rendered HTML.',
-          'Hydration failed because the initial UI does not match what was rendered on the server.',
-          'There was an error while hydrating. Because the error happened outside of a Suspense boundary, the entire root will switch to client rendering.',
-        ]);
+        expect(errors).toEqual(
+          [
+            gate(flags => flags.enableClientRenderFallbackOnTextMismatch)
+              ? 'Text content does not match server-rendered HTML.'
+              : null,
+            'Hydration failed because the initial UI does not match what was rendered on the server.',
+            'There was an error while hydrating. Because the error happened outside of a Suspense boundary, the entire root will switch to client rendering.',
+          ].filter(Boolean),
+        );
         expect(getVisibleChildren(container)).toEqual(
           <title>{['hello1', 'hello2']}</title>,
         );

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

@@ -86,7 +86,8 @@ describe('ReactDOMServerHydration', () => {
           </div>
         );
       }
-      expect(testMismatch(Mismatch)).toMatchInlineSnapshot(`
+      if (gate(flags => flags.enableClientRenderFallbackOnTextMismatch)) {
+        expect(testMismatch(Mismatch)).toMatchInlineSnapshot(`
           Array [
             "Warning: Text content did not match. Server: \\"server\\" Client: \\"client\\"
               in main (at **)
@@ -97,6 +98,16 @@ describe('ReactDOMServerHydration', () => {
             "Caught [There was an error while hydrating. Because the error happened outside of a Suspense boundary, the entire root will switch to client rendering.]",
           ]
         `);
+      } else {
+        expect(testMismatch(Mismatch)).toMatchInlineSnapshot(`
+          Array [
+            "Warning: Text content did not match. Server: \\"server\\" Client: \\"client\\"
+              in main (at **)
+              in div (at **)
+              in Mismatch (at **)",
+          ]
+        `);
+      }
     });
 
     // @gate __DEV__
@@ -346,7 +357,8 @@ describe('ReactDOMServerHydration', () => {
         function Mismatch({isClient}) {
           return <div className="parent">{isClient && 'only'}</div>;
         }
-        expect(testMismatch(Mismatch)).toMatchInlineSnapshot(`
+        if (gate(flags => flags.enableClientRenderFallbackOnTextMismatch)) {
+          expect(testMismatch(Mismatch)).toMatchInlineSnapshot(`
             Array [
               "Warning: Text content did not match. Server: \\"\\" Client: \\"only\\"
                 in div (at **)
@@ -356,6 +368,15 @@ describe('ReactDOMServerHydration', () => {
               "Caught [There was an error while hydrating. Because the error happened outside of a Suspense boundary, the entire root will switch to client rendering.]",
             ]
           `);
+        } else {
+          expect(testMismatch(Mismatch)).toMatchInlineSnapshot(`
+            Array [
+              "Warning: Text content did not match. Server: \\"\\" Client: \\"only\\"
+                in div (at **)
+                in Mismatch (at **)",
+            ]
+          `);
+        }
       });
 
       // @gate __DEV__

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

@@ -3416,6 +3416,7 @@ describe('ReactDOMServerPartialHydration', () => {
     );
   });
 
+  // @gate enableClientRenderFallbackOnTextMismatch
   it("falls back to client rendering when there's a text mismatch (direct text child)", async () => {
     function DirectTextChild({text}) {
       return <div>{text}</div>;
@@ -3447,6 +3448,7 @@ describe('ReactDOMServerPartialHydration', () => {
     ]);
   });
 
+  // @gate enableClientRenderFallbackOnTextMismatch
   it("falls back to client rendering when there's a text mismatch (text child with siblings)", async () => {
     function Sibling() {
       return 'Sibling';

packages/react-dom/src/client/ReactDOMComponent.js

@@ -72,6 +72,7 @@ import {validateProperties as validateUnknownProperties} from '../shared/ReactDO
 import {
   enableTrustedTypesIntegration,
   enableCustomElementPropertySupport,
+  enableClientRenderFallbackOnTextMismatch,
 } from 'shared/ReactFeatureFlags';
 import {
   mediaEventTypes,
@@ -249,7 +250,7 @@ export function checkForUnmatchedText(
     }
   }
 
-  if (isConcurrentMode) {
+  if (isConcurrentMode && enableClientRenderFallbackOnTextMismatch) {
     // In concurrent roots, we throw when there's a text mismatch and revert to
     // client rendering, up to the nearest Suspense boundary.
     throw new Error('Text content does not match server-rendered HTML.');

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

@@ -169,6 +169,7 @@ describe('useMutableSourceHydration', () => {
   });
 
   // @gate enableUseMutableSource
+  // @gate enableClientRenderFallbackOnTextMismatch
   it('should detect a tear before hydrating a component', () => {
     const source = createSource('one');
     const mutableSource = createMutableSource(source, param => param.version);

packages/shared/ReactFeatureFlags.js

@@ -31,6 +31,9 @@ export const enableSymbolFallbackForWWW = false;
 // internal tests need to be updated. The open source behavior is correct.
 export const skipUnmountedBoundaries = true;
 
+// TODO: Finish rolling out in www
+export const enableClientRenderFallbackOnTextMismatch = true;
+
 // TODO: Need to review this code one more time before landing
 export const enableCapturePhaseSelectiveHydrationWithoutDiscreteEventReplay = true;
 

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

@@ -51,6 +51,7 @@ export const enableSuspenseAvoidThisFallback = false;
 export const enableSuspenseAvoidThisFallbackFizz = false;
 export const enableCPUSuspense = true;
 export const enableCapturePhaseSelectiveHydrationWithoutDiscreteEventReplay = true;
+export const enableClientRenderFallbackOnTextMismatch = true;
 export const enableComponentStackLocations = false;
 export const enableLegacyFBSupport = false;
 export const enableFilterEmptyStringAttributesDOM = false;

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

@@ -41,6 +41,7 @@ export const enableSuspenseAvoidThisFallback = false;
 export const enableSuspenseAvoidThisFallbackFizz = false;
 export const enableCPUSuspense = false;
 export const enableCapturePhaseSelectiveHydrationWithoutDiscreteEventReplay = true;
+export const enableClientRenderFallbackOnTextMismatch = true;
 export const enableComponentStackLocations = false;
 export const enableLegacyFBSupport = false;
 export const enableFilterEmptyStringAttributesDOM = false;

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

@@ -41,6 +41,7 @@ export const enableSuspenseAvoidThisFallback = false;
 export const enableSuspenseAvoidThisFallbackFizz = false;
 export const enableCPUSuspense = false;
 export const enableCapturePhaseSelectiveHydrationWithoutDiscreteEventReplay = true;
+export const enableClientRenderFallbackOnTextMismatch = true;
 export const enableComponentStackLocations = true;
 export const enableLegacyFBSupport = false;
 export const enableFilterEmptyStringAttributesDOM = false;

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

@@ -50,6 +50,7 @@ export const enableSuspenseAvoidThisFallback = false;
 export const enableSuspenseAvoidThisFallbackFizz = false;
 export const enableCPUSuspense = false;
 export const enableCapturePhaseSelectiveHydrationWithoutDiscreteEventReplay = true;
+export const enableClientRenderFallbackOnTextMismatch = true;
 export const enableStrictEffects = false;
 export const createRootStrictEffectsByDefault = false;
 export const enableUseRefAccessWarning = false;

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

@@ -41,6 +41,7 @@ export const enableSuspenseAvoidThisFallback = true;
 export const enableSuspenseAvoidThisFallbackFizz = false;
 export const enableCPUSuspense = false;
 export const enableCapturePhaseSelectiveHydrationWithoutDiscreteEventReplay = true;
+export const enableClientRenderFallbackOnTextMismatch = true;
 export const enableComponentStackLocations = true;
 export const enableLegacyFBSupport = false;
 export const enableFilterEmptyStringAttributesDOM = false;

packages/shared/forks/ReactFeatureFlags.testing.js

@@ -41,6 +41,7 @@ export const enableSuspenseAvoidThisFallback = false;
 export const enableSuspenseAvoidThisFallbackFizz = false;
 export const enableCPUSuspense = false;
 export const enableCapturePhaseSelectiveHydrationWithoutDiscreteEventReplay = true;
+export const enableClientRenderFallbackOnTextMismatch = true;
 export const enableComponentStackLocations = true;
 export const enableLegacyFBSupport = false;
 export const enableFilterEmptyStringAttributesDOM = false;

packages/shared/forks/ReactFeatureFlags.testing.www.js

@@ -41,6 +41,7 @@ export const enableSuspenseAvoidThisFallback = true;
 export const enableSuspenseAvoidThisFallbackFizz = false;
 export const enableCPUSuspense = true;
 export const enableCapturePhaseSelectiveHydrationWithoutDiscreteEventReplay = true;
+export const enableClientRenderFallbackOnTextMismatch = true;
 export const enableComponentStackLocations = true;
 export const enableLegacyFBSupport = !__EXPERIMENTAL__;
 export const enableFilterEmptyStringAttributesDOM = false;

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

@@ -26,6 +26,7 @@ export const enableLazyContextPropagation = __VARIANT__;
 export const enableSyncDefaultUpdates = __VARIANT__;
 export const consoleManagedByDevToolsDuringStrictMode = __VARIANT__;
 export const enableCapturePhaseSelectiveHydrationWithoutDiscreteEventReplay = __VARIANT__;
+export const enableClientRenderFallbackOnTextMismatch = __VARIANT__;
 export const enableTransitionTracing = __VARIANT__;
 export const enableSymbolFallbackForWWW = __VARIANT__;
 // Enable this flag to help with concurrent mode debugging.

packages/shared/forks/ReactFeatureFlags.www.js

@@ -32,6 +32,7 @@ export const {
   enableLazyContextPropagation,
   enableSyncDefaultUpdates,
   enableCapturePhaseSelectiveHydrationWithoutDiscreteEventReplay,
+  enableClientRenderFallbackOnTextMismatch,
 } = dynamicFeatureFlags;
 
 // On WWW, __EXPERIMENTAL__ is used for a new modern build.