Disable IE innerHTML workaround behind a flag

We don't need this workaround for SVG anymore and we don't need to
workaround MSApp's security model since Windows 10.

Author: sebmarkbage

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

@@ -74,6 +74,7 @@ import {
   enableCustomElementPropertySupport,
   enableClientRenderFallbackOnTextMismatch,
   enableHostSingletons,
+  disableIEWorkarounds,
 } from 'shared/ReactFeatureFlags';
 import {
   mediaEventTypes,
@@ -132,7 +133,8 @@ if (__DEV__) {
   // normalized. Since it only affects IE, we're skipping style warnings
   // in that browser completely in favor of doing all that work.
   // See https://github.com/facebook/react/issues/11807
-  canDiffStyleForHydrationWarning = canUseDOM && !document.documentMode;
+  canDiffStyleForHydrationWarning =
+    disableIEWorkarounds || (canUseDOM && !document.documentMode);
 
   warnForPropDifference = function (
     propName: string,
@@ -308,7 +310,11 @@ function setInitialDOMProperties(
     } else if (propKey === DANGEROUSLY_SET_INNER_HTML) {
       const nextHtml = nextProp ? nextProp[HTML] : undefined;
       if (nextHtml != null) {
-        setInnerHTML(domElement, nextHtml);
+        if (disableIEWorkarounds) {
+          domElement.innerHTML = nextHtml;
+        } else {
+          setInnerHTML(domElement, nextHtml);
+        }
       }
     } else if (propKey === CHILDREN) {
       if (typeof nextProp === 'string') {
@@ -366,7 +372,11 @@ function updateDOMProperties(
     if (propKey === STYLE) {
       setValueForStyles(domElement, propValue);
     } else if (propKey === DANGEROUSLY_SET_INNER_HTML) {
-      setInnerHTML(domElement, propValue);
+      if (disableIEWorkarounds) {
+        domElement.innerHTML = propValue;
+      } else {
+        setInnerHTML(domElement, propValue);
+      }
     } else if (propKey === CHILDREN) {
       setTextContent(domElement, propValue);
     } else {

packages/shared/ReactFeatureFlags.js

@@ -169,6 +169,9 @@ export const enableTrustedTypesIntegration = false;
 // DOM properties
 export const disableInputAttributeSyncing = false;
 
+// Remove IE and MsApp specific workarounds for innerHTML
+export const disableIEWorkarounds = __EXPERIMENTAL__;
+
 // Filter certain DOM attributes (e.g. src, href) if their values are empty
 // strings. This prevents e.g. <img src=""> from making an unnecessary HTTP
 // request for certain browsers.

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

@@ -36,6 +36,7 @@ export const debugRenderPhaseSideEffectsForStrictMode = true;
 export const disableJavaScriptURLs = false;
 export const disableCommentsAsDOMContainers = true;
 export const disableInputAttributeSyncing = false;
+export const disableIEWorkarounds = true;
 export const replayFailedUnitOfWorkWithInvokeGuardedCallback = __DEV__;
 export const enableScopeAPI = false;
 export const enableCreateEventHandleAPI = false;

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

@@ -26,6 +26,7 @@ export const enableFetchInstrumentation = false;
 export const disableJavaScriptURLs = false;
 export const disableCommentsAsDOMContainers = true;
 export const disableInputAttributeSyncing = false;
+export const disableIEWorkarounds = true;
 export const enableSchedulerDebugging = false;
 export const enableScopeAPI = false;
 export const enableCreateEventHandleAPI = false;

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

@@ -26,6 +26,7 @@ export const enableFetchInstrumentation = true;
 export const disableJavaScriptURLs = false;
 export const disableCommentsAsDOMContainers = true;
 export const disableInputAttributeSyncing = false;
+export const disableIEWorkarounds = true;
 export const enableSchedulerDebugging = false;
 export const enableScopeAPI = false;
 export const enableCreateEventHandleAPI = false;

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

@@ -26,6 +26,7 @@ export const enableFetchInstrumentation = false;
 export const disableJavaScriptURLs = false;
 export const disableCommentsAsDOMContainers = true;
 export const disableInputAttributeSyncing = false;
+export const disableIEWorkarounds = true;
 export const enableSchedulerDebugging = false;
 export const enableScopeAPI = false;
 export const enableCreateEventHandleAPI = false;

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

@@ -27,6 +27,7 @@ export const enableSchedulerDebugging = false;
 export const disableJavaScriptURLs = false;
 export const disableCommentsAsDOMContainers = true;
 export const disableInputAttributeSyncing = false;
+export const disableIEWorkarounds = true;
 export const enableScopeAPI = true;
 export const enableCreateEventHandleAPI = false;
 export const enableSuspenseCallback = true;

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

@@ -14,6 +14,7 @@
 // with the __VARIANT__ set to `true`, and once set to `false`.
 
 export const disableInputAttributeSyncing = __VARIANT__;
+export const disableIEWorkarounds = __VARIANT__;
 export const enableFilterEmptyStringAttributesDOM = __VARIANT__;
 export const enableLegacyFBSupport = __VARIANT__;
 export const skipUnmountedBoundaries = __VARIANT__;

packages/shared/forks/ReactFeatureFlags.www.js

@@ -16,6 +16,7 @@ const dynamicFeatureFlags: DynamicFeatureFlags = require('ReactFeatureFlags');
 
 export const {
   disableInputAttributeSyncing,
+  disableIEWorkarounds,
   enableTrustedTypesIntegration,
   disableSchedulerTimeoutBasedOnReactExpirationTime,
   replayFailedUnitOfWorkWithInvokeGuardedCallback,