facebook · acdlite · May 14, 2020 · May 14, 2020
diff --git a/packages/react-dom/src/__tests__/ReactUpdates-test.js b/packages/react-dom/src/__tests__/ReactUpdates-test.js
@@ -29,15 +29,19 @@ describe('ReactUpdates', () => {
   function LegacyHiddenDiv({hidden, children, ...props}) {
     if (gate(flags => flags.new)) {
       return (
-        <div hidden={hidden} {...props}>
+        <div
+          hidden={hidden ? 'unstable-do-not-use-legacy-hidden' : false}
+          {...props}>
           <React.unstable_LegacyHidden mode={hidden ? 'hidden' : 'visible'}>
             {children}
           </React.unstable_LegacyHidden>
         </div>
       );
     } else {
       return (
-        <div hidden={hidden} {...props}>
+        <div
+          hidden={hidden ? 'unstable-do-not-use-legacy-hidden' : false}
+          {...props}>
           {children}
         </div>
       );

diff --git a/packages/react-dom/src/client/ReactDOMHostConfig.js b/packages/react-dom/src/client/ReactDOMHostConfig.js
@@ -78,6 +78,7 @@ import {
   enableModernEventSystem,
   enableCreateEventHandleAPI,
   enableScopeAPI,
+  disableHiddenPropDeprioritization,
 } from 'shared/ReactFeatureFlags';
 import {HostComponent, HostText} from 'react-reconciler/src/ReactWorkTags';
 import {TOP_BEFORE_BLUR, TOP_AFTER_BLUR} from '../events/DOMTopLevelEventTypes';
@@ -372,7 +373,14 @@ export function shouldSetTextContent(type: string, props: Props): boolean {
 }
 
 export function shouldDeprioritizeSubtree(type: string, props: Props): boolean {
-  return !!props.hidden;
+  if (disableHiddenPropDeprioritization) {
+    // This is obnoxiously specific so that nobody uses it, but we can still opt
+    // in via an infra-level userspace abstraction.
+    return props.hidden === 'unstable-do-not-use-legacy-hidden';
+  } else {
+    // Legacy behavior. Any truthy value works.
+    return !!props.hidden;
+  }
 }
 
 export function createTextInstance(

diff --git a/packages/react-reconciler/src/ReactFiberBeginWork.new.js b/packages/react-reconciler/src/ReactFiberBeginWork.new.js
@@ -75,7 +75,6 @@ import {
   warnAboutDefaultPropsOnFunctionComponents,
   enableScopeAPI,
   enableBlocksAPI,
-  warnAboutDOMHiddenAttribute,
 } from 'shared/ReactFeatureFlags';
 import invariant from 'shared/invariant';
 import shallowEqual from 'shared/shallowEqual';
@@ -1124,22 +1123,6 @@ function updateHostComponent(
   }
 
   markRef(current, workInProgress);
-
-  if (__DEV__) {
-    if (
-      warnAboutDOMHiddenAttribute &&
-      (workInProgress.mode & ConcurrentMode) !== NoMode &&
-      nextProps.hasOwnProperty('hidden')
-    ) {
-      // This warning will not be user visible. Only exists so React Core team
-      // can find existing callers and migrate them to the new API.
-      console.error(
-        'Detected use of DOM `hidden` attribute. Should migrate to new API. ' +
-          '(owner: React Core)',
-      );
-    }
-  }
-
   reconcileChildren(current, workInProgress, nextChildren, renderLanes);
   return workInProgress.child;
 }

diff --git a/packages/react-reconciler/src/ReactFiberBeginWork.old.js b/packages/react-reconciler/src/ReactFiberBeginWork.old.js
@@ -69,7 +69,6 @@ import {
   warnAboutDefaultPropsOnFunctionComponents,
   enableScopeAPI,
   enableBlocksAPI,
-  warnAboutDOMHiddenAttribute,
 } from 'shared/ReactFeatureFlags';
 import invariant from 'shared/invariant';
 import shallowEqual from 'shared/shallowEqual';
@@ -1100,21 +1099,6 @@ function updateHostComponent(current, workInProgress, renderExpirationTime) {
 
   markRef(current, workInProgress);
 
-  if (__DEV__) {
-    if (
-      warnAboutDOMHiddenAttribute &&
-      (workInProgress.mode & ConcurrentMode) !== NoMode &&
-      nextProps.hasOwnProperty('hidden')
-    ) {
-      // This warning will not be user visible. Only exists so React Core team
-      // can find existing callers and migrate them to the new API.
-      console.error(
-        'Detected use of DOM `hidden` attribute. Should migrate to new API. ' +
-          '(owner: React Core)',
-      );
-    }
-  }
-
   // Check the host config to see if the children are offscreen/hidden.
   if (
     workInProgress.mode & ConcurrentMode &&

diff --git a/packages/react-refresh/src/__tests__/ReactFresh-test.js b/packages/react-refresh/src/__tests__/ReactFresh-test.js
@@ -79,15 +79,19 @@ describe('ReactFresh', () => {
   function LegacyHiddenDiv({hidden, children, ...props}) {
     if (gate(flags => flags.new)) {
       return (
-        <div hidden={hidden} {...props}>
+        <div
+          hidden={hidden ? 'unstable-do-not-use-legacy-hidden' : false}
+          {...props}>
           <React.unstable_LegacyHidden mode={hidden ? 'hidden' : 'visible'}>
             {children}
           </React.unstable_LegacyHidden>
         </div>
       );
     } else {
       return (
-        <div hidden={hidden} {...props}>
+        <div
+          hidden={hidden ? 'unstable-do-not-use-legacy-hidden' : false}
+          {...props}>
           {children}
         </div>
       );

diff --git a/packages/react/src/__tests__/ReactDOMTracing-test.internal.js b/packages/react/src/__tests__/ReactDOMTracing-test.internal.js
@@ -59,15 +59,19 @@ function loadModules() {
 function LegacyHiddenDiv({hidden, children, ...props}) {
   if (gate(flags => flags.new)) {
     return (
-      <div hidden={hidden} {...props}>
+      <div
+        hidden={hidden ? 'unstable-do-not-use-legacy-hidden' : false}
+        {...props}>
         <React.unstable_LegacyHidden mode={hidden ? 'hidden' : 'visible'}>
           {children}
         </React.unstable_LegacyHidden>
       </div>
     );
   } else {
     return (
-      <div hidden={hidden} {...props}>
+      <div
+        hidden={hidden ? 'unstable-do-not-use-legacy-hidden' : false}
+        {...props}>
         {children}
       </div>
     );

diff --git a/packages/shared/ReactFeatureFlags.js b/packages/shared/ReactFeatureFlags.js
@@ -140,4 +140,4 @@ export const enableLegacyFBSupport = false;
 export const deferRenderPhaseUpdateToNextBatch = true;
 
 // Flag used by www build so we can log occurrences of legacy hidden API
-export const warnAboutDOMHiddenAttribute = false;
+export const disableHiddenPropDeprioritization = true;
diff --git a/packages/shared/forks/ReactFeatureFlags.native-fb.js b/packages/shared/forks/ReactFeatureFlags.native-fb.js
@@ -48,7 +48,7 @@ export const enableFilterEmptyStringAttributesDOM = false;
 
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;
-export const warnAboutDOMHiddenAttribute = false;
+export const disableHiddenPropDeprioritization = true;
 
 // Flow magic to verify the exports of this file match the original version.
 // eslint-disable-next-line no-unused-vars

diff --git a/packages/shared/forks/ReactFeatureFlags.native-oss.js b/packages/shared/forks/ReactFeatureFlags.native-oss.js
@@ -47,7 +47,7 @@ export const enableFilterEmptyStringAttributesDOM = false;
 
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;
-export const warnAboutDOMHiddenAttribute = false;
+export const disableHiddenPropDeprioritization = true;
 
 // Flow magic to verify the exports of this file match the original version.
 // eslint-disable-next-line no-unused-vars

diff --git a/packages/shared/forks/ReactFeatureFlags.test-renderer.js b/packages/shared/forks/ReactFeatureFlags.test-renderer.js
@@ -47,7 +47,7 @@ export const enableFilterEmptyStringAttributesDOM = false;
 
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;
-export const warnAboutDOMHiddenAttribute = false;
+export const disableHiddenPropDeprioritization = true;
 
 // Flow magic to verify the exports of this file match the original version.
 // eslint-disable-next-line no-unused-vars

diff --git a/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js b/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js
@@ -47,7 +47,7 @@ export const enableFilterEmptyStringAttributesDOM = false;
 
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;
-export const warnAboutDOMHiddenAttribute = false;
+export const disableHiddenPropDeprioritization = true;
 
 // Flow magic to verify the exports of this file match the original version.
 // eslint-disable-next-line no-unused-vars

diff --git a/packages/shared/forks/ReactFeatureFlags.testing.js b/packages/shared/forks/ReactFeatureFlags.testing.js
@@ -47,7 +47,7 @@ export const enableFilterEmptyStringAttributesDOM = false;
 
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;
-export const warnAboutDOMHiddenAttribute = false;
+export const disableHiddenPropDeprioritization = true;
 
 // Flow magic to verify the exports of this file match the original version.
 // eslint-disable-next-line no-unused-vars

diff --git a/packages/shared/forks/ReactFeatureFlags.testing.www.js b/packages/shared/forks/ReactFeatureFlags.testing.www.js
@@ -47,7 +47,7 @@ export const enableFilterEmptyStringAttributesDOM = false;
 
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;
-export const warnAboutDOMHiddenAttribute = false;
+export const disableHiddenPropDeprioritization = true;
 
 // Flow magic to verify the exports of this file match the original version.
 // eslint-disable-next-line no-unused-vars

diff --git a/packages/shared/forks/ReactFeatureFlags.www-dynamic.js b/packages/shared/forks/ReactFeatureFlags.www-dynamic.js
@@ -21,6 +21,9 @@ export const enableModernEventSystem = __VARIANT__;
 export const enableLegacyFBSupport = __VARIANT__;
 export const enableDebugTracing = !__VARIANT__;
 
+// Temporary flag, in case we need to re-enable this feature.
+export const disableHiddenPropDeprioritization = __VARIANT__;
+
 // This only has an effect in the new reconciler. But also, the new reconciler
 // is only enabled when __VARIANT__ is true. So this is set to the opposite of
 // __VARIANT__ so that it's `false` when running against the new reconciler.
@@ -36,13 +39,6 @@ export const deferRenderPhaseUpdateToNextBatch = !__VARIANT__;
 export const debugRenderPhaseSideEffectsForStrictMode = __DEV__;
 export const replayFailedUnitOfWorkWithInvokeGuardedCallback = __DEV__;
 
-// Do not add the corresponding warning to the warning filter! Only exists so we
-// can detect callers and migrate them to the new API. Should not visible to
-// anyone outside React Core team.
-//
-// Disabled in our tests, but we'll enable in www.
-export const warnAboutDOMHiddenAttribute = false;
-
 // TODO: These flags are hard-coded to the default values used in open source.
 // Update the tests so that they pass in either mode, then set these
 // to __VARIANT__.

diff --git a/packages/shared/forks/ReactFeatureFlags.www.js b/packages/shared/forks/ReactFeatureFlags.www.js
@@ -27,7 +27,7 @@ export const {
   enableLegacyFBSupport,
   enableDebugTracing,
   deferRenderPhaseUpdateToNextBatch,
-  warnAboutDOMHiddenAttribute,
+  disableHiddenPropDeprioritization,
 } = dynamicFeatureFlags;
 
 // On WWW, __EXPERIMENTAL__ is used for a new modern build.