From 7a2609eedc571049a3272e60d5f7d84601ffca3f Mon Sep 17 00:00:00 2001
From: Jan Kassens <jkassens@meta.com>
Date: Wed, 3 Apr 2024 09:25:02 -0400
Subject: [PATCH] Cleanup enableBigIntSupport flag (#28711)

Cleanup enableBigIntSupport flag
---
 .../src/client/ReactDOMComponent.js           | 13 ++-----
 .../src/client/ReactDOMOption.js              |  3 +-
 .../src/client/ReactFiberConfigDOM.js         |  3 +-
 .../src/client/ToStringValue.js               |  6 ----
 .../src/server/ReactFizzConfigDOM.js          | 16 +++------
 .../src/server/escapeTextForBrowser.js        |  3 +-
 .../src/__tests__/ReactDOMFiber-test.js       |  1 -
 .../src/__tests__/ReactDOMFizzServer-test.js  | 13 ++-----
 .../src/__tests__/ReactDOMInput-test.js       |  1 -
 .../src/__tests__/ReactDOMOption-test.js      |  1 -
 .../ReactDOMServerIntegrationBasic-test.js    |  8 ++---
 .../ReactDOMServerIntegrationInput-test.js    | 11 ++----
 .../ReactDOMServerIntegrationSelect-test.js   |  4 +--
 .../ReactDOMServerIntegrationTextarea-test.js | 11 ++----
 .../src/__tests__/ReactDOMTextarea-test.js    |  1 -
 .../src/__tests__/ReactMultiChildText-test.js |  1 -
 .../react-reconciler/src/ReactChildFiber.js   |  9 +++--
 .../src/__tests__/ReactTopLevelText-test.js   |  1 -
 packages/react-server/src/ReactFizzServer.js  |  6 +---
 packages/react/src/ReactChildren.js           |  5 ---
 .../react/src/__tests__/ReactChildren-test.js | 36 ++++++-------------
 packages/shared/ReactFeatureFlags.js          |  2 --
 .../ReactFeatureFlags.native-fb-dynamic.js    |  1 -
 .../forks/ReactFeatureFlags.native-fb.js      |  1 -
 .../forks/ReactFeatureFlags.native-oss.js     |  1 -
 .../forks/ReactFeatureFlags.test-renderer.js  |  1 -
 ...actFeatureFlags.test-renderer.native-fb.js |  2 --
 .../ReactFeatureFlags.test-renderer.www.js    |  2 --
 .../forks/ReactFeatureFlags.www-dynamic.js    |  1 -
 .../shared/forks/ReactFeatureFlags.www.js     |  1 -
 30 files changed, 36 insertions(+), 129 deletions(-)

diff --git a/packages/react-dom-bindings/src/client/ReactDOMComponent.js b/packages/react-dom-bindings/src/client/ReactDOMComponent.js
index 4df6de538576..673fd47eca46 100644
--- a/packages/react-dom-bindings/src/client/ReactDOMComponent.js
+++ b/packages/react-dom-bindings/src/client/ReactDOMComponent.js
@@ -66,7 +66,6 @@ import {validateProperties as validateUnknownProperties} from '../shared/ReactDO
 import sanitizeURL from '../shared/sanitizeURL';
 
 import {
-  enableBigIntSupport,
   disableIEWorkarounds,
   enableTrustedTypesIntegration,
   enableFilterEmptyStringAttributesDOM,
@@ -370,10 +369,7 @@ function setProp(
         if (canSetTextContent) {
           setTextContent(domElement, value);
         }
-      } else if (
-        typeof value === 'number' ||
-        (enableBigIntSupport && typeof value === 'bigint')
-      ) {
+      } else if (typeof value === 'number' || typeof value === 'bigint') {
         if (__DEV__) {
           // $FlowFixMe[unsafe-addition] Flow doesn't want us to use `+` operator with string and bigint
           validateTextNesting('' + value, tag);
@@ -929,10 +925,7 @@ function setPropOnCustomElement(
     case 'children': {
       if (typeof value === 'string') {
         setTextContent(domElement, value);
-      } else if (
-        typeof value === 'number' ||
-        (enableBigIntSupport && typeof value === 'bigint')
-      ) {
+      } else if (typeof value === 'number' || typeof value === 'bigint') {
         // $FlowFixMe[unsafe-addition] Flow doesn't want us to use `+` operator with string and bigint
         setTextContent(domElement, '' + value);
       }
@@ -2948,7 +2941,7 @@ export function hydrateProperties(
   if (
     typeof children === 'string' ||
     typeof children === 'number' ||
-    (enableBigIntSupport && typeof children === 'bigint')
+    typeof children === 'bigint'
   ) {
     if (
       // $FlowFixMe[unsafe-addition] Flow doesn't want us to use `+` operator with string and bigint
diff --git a/packages/react-dom-bindings/src/client/ReactDOMOption.js b/packages/react-dom-bindings/src/client/ReactDOMOption.js
index 10d04bd6f7eb..ae7a7ba999c0 100644
--- a/packages/react-dom-bindings/src/client/ReactDOMOption.js
+++ b/packages/react-dom-bindings/src/client/ReactDOMOption.js
@@ -8,7 +8,6 @@
  */
 
 import {Children} from 'react';
-import {enableBigIntSupport} from 'shared/ReactFeatureFlags';
 
 let didWarnSelectedSetOnOption = false;
 let didWarnInvalidChild = false;
@@ -30,7 +29,7 @@ export function validateOptionProps(element: Element, props: Object) {
           if (
             typeof child === 'string' ||
             typeof child === 'number' ||
-            (enableBigIntSupport && typeof child === 'bigint')
+            typeof child === 'bigint'
           ) {
             return;
           }
diff --git a/packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js b/packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js
index d67571fc41e1..9b9f41a92d37 100644
--- a/packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js
+++ b/packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js
@@ -84,7 +84,6 @@ import {
 import {retryIfBlockedOn} from '../events/ReactDOMEventReplaying';
 
 import {
-  enableBigIntSupport,
   enableCreateEventHandleAPI,
   enableScopeAPI,
   enableTrustedTypesIntegration,
@@ -546,7 +545,7 @@ export function shouldSetTextContent(type: string, props: Props): boolean {
     type === 'noscript' ||
     typeof props.children === 'string' ||
     typeof props.children === 'number' ||
-    (enableBigIntSupport && typeof props.children === 'bigint') ||
+    typeof props.children === 'bigint' ||
     (typeof props.dangerouslySetInnerHTML === 'object' &&
       props.dangerouslySetInnerHTML !== null &&
       props.dangerouslySetInnerHTML.__html != null)
diff --git a/packages/react-dom-bindings/src/client/ToStringValue.js b/packages/react-dom-bindings/src/client/ToStringValue.js
index e1fc51b775dd..46708f2f7695 100644
--- a/packages/react-dom-bindings/src/client/ToStringValue.js
+++ b/packages/react-dom-bindings/src/client/ToStringValue.js
@@ -8,7 +8,6 @@
  */
 
 import {checkFormFieldValueStringCoercion} from 'shared/CheckStringCoercion';
-import {enableBigIntSupport} from 'shared/ReactFeatureFlags';
 
 export opaque type ToStringValue =
   | boolean
@@ -31,11 +30,6 @@ export function toString(value: ToStringValue): string {
 export function getToStringValue(value: mixed): ToStringValue {
   switch (typeof value) {
     case 'bigint':
-      if (!enableBigIntSupport) {
-        // bigint is assigned as empty string
-        return '';
-      }
-    // fallthrough for BigInt support
     case 'boolean':
     case 'number':
     case 'string':
diff --git a/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js b/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js
index 623bedd92e6e..475e934a6049 100644
--- a/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js
+++ b/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js
@@ -28,7 +28,6 @@ import {
 import {Children} from 'react';
 
 import {
-  enableBigIntSupport,
   enableFilterEmptyStringAttributesDOM,
   enableFizzExternalRuntime,
 } from 'shared/ReactFeatureFlags';
@@ -1664,8 +1663,7 @@ function flattenOptionChildren(children: mixed): string {
         !didWarnInvalidOptionChildren &&
         typeof child !== 'string' &&
         typeof child !== 'number' &&
-        ((enableBigIntSupport && typeof child !== 'bigint') ||
-          !enableBigIntSupport)
+        typeof child !== 'bigint'
       ) {
         didWarnInvalidOptionChildren = true;
         console.error(
@@ -2983,40 +2981,36 @@ function pushTitle(
 
       if (Array.isArray(children) && children.length > 1) {
         console.error(
-          'React expects the `children` prop of <title> tags to be a string, number%s, or object with a novel `toString` method but found an Array with length %s instead.' +
+          'React expects the `children` prop of <title> tags to be a string, number, bigint, or object with a novel `toString` method but found an Array with length %s instead.' +
             ' Browsers treat all child Nodes of <title> tags as Text content and React expects to be able to convert `children` of <title> tags to a single string value' +
             ' which is why Arrays of length greater than 1 are not supported. When using JSX it can be commong to combine text nodes and value nodes.' +
             ' For example: <title>hello {nameOfUser}</title>. While not immediately apparent, `children` in this case is an Array with length 2. If your `children` prop' +
             ' is using this form try rewriting it using a template string: <title>{`hello ${nameOfUser}`}</title>.',
-          enableBigIntSupport ? ', bigint' : '',
           children.length,
         );
       } else if (typeof child === 'function' || typeof child === 'symbol') {
         const childType =
           typeof child === 'function' ? 'a Function' : 'a Sybmol';
         console.error(
-          'React expect children of <title> tags to be a string, number%s, or object with a novel `toString` method but found %s instead.' +
+          'React expect children of <title> tags to be a string, number, bigint, or object with a novel `toString` method but found %s instead.' +
             ' Browsers treat all child Nodes of <title> tags as Text content and React expects to be able to convert children of <title>' +
             ' tags to a single string value.',
-          enableBigIntSupport ? ', bigint' : '',
           childType,
         );
       } else if (child && child.toString === {}.toString) {
         if (child.$$typeof != null) {
           console.error(
-            'React expects the `children` prop of <title> tags to be a string, number%s, or object with a novel `toString` method but found an object that appears to be' +
+            'React expects the `children` prop of <title> tags to be a string, number, bigint, or object with a novel `toString` method but found an object that appears to be' +
               ' a React element which never implements a suitable `toString` method. Browsers treat all child Nodes of <title> tags as Text content and React expects to' +
               ' be able to convert children of <title> tags to a single string value which is why rendering React elements is not supported. If the `children` of <title> is' +
               ' a React Component try moving the <title> tag into that component. If the `children` of <title> is some HTML markup change it to be Text only to be valid HTML.',
-            enableBigIntSupport ? ', bigint' : '',
           );
         } else {
           console.error(
-            'React expects the `children` prop of <title> tags to be a string, number%s, or object with a novel `toString` method but found an object that does not implement' +
+            'React expects the `children` prop of <title> tags to be a string, number, bigint, or object with a novel `toString` method but found an object that does not implement' +
               ' a suitable `toString` method. Browsers treat all child Nodes of <title> tags as Text content and React expects to be able to convert children of <title> tags' +
               ' to a single string value. Using the default `toString` method available on every object is almost certainly an error. Consider whether the `children` of this <title>' +
               ' is an object in error and change it to a string or number value if so. Otherwise implement a `toString` method that React can use to produce a valid <title>.',
-            enableBigIntSupport ? ', bigint' : '',
           );
         }
       }
diff --git a/packages/react-dom-bindings/src/server/escapeTextForBrowser.js b/packages/react-dom-bindings/src/server/escapeTextForBrowser.js
index 6fd43c01c5f6..4514bf66831d 100644
--- a/packages/react-dom-bindings/src/server/escapeTextForBrowser.js
+++ b/packages/react-dom-bindings/src/server/escapeTextForBrowser.js
@@ -39,7 +39,6 @@
  */
 
 import {checkHtmlStringCoercion} from 'shared/CheckStringCoercion';
-import {enableBigIntSupport} from 'shared/ReactFeatureFlags';
 
 const matchHtmlRegExp = /["'&<>]/;
 
@@ -110,7 +109,7 @@ function escapeTextForBrowser(text: string | number | boolean): string {
   if (
     typeof text === 'boolean' ||
     typeof text === 'number' ||
-    (enableBigIntSupport && typeof text === 'bigint')
+    typeof text === 'bigint'
   ) {
     // this shortcircuit helps perf for types that we know will never have
     // special characters, especially given that this function is used often
diff --git a/packages/react-dom/src/__tests__/ReactDOMFiber-test.js b/packages/react-dom/src/__tests__/ReactDOMFiber-test.js
index f135bd288d19..a1633fa1e625 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFiber-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFiber-test.js
@@ -60,7 +60,6 @@ describe('ReactDOMFiber', () => {
     expect(container.textContent).toEqual('10');
   });
 
-  // @gate enableBigIntSupport
   it('should render bigints as children', async () => {
     const Box = ({value}) => <div>{value}</div>;
 
diff --git a/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js b/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
index 2949443871c6..6064ad9312e8 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
@@ -3377,7 +3377,6 @@ describe('ReactDOMFizzServer', () => {
     );
   });
 
-  // @gate enableBigIntSupport
   it('Supports bigint', async () => {
     await act(async () => {
       const {pipe} = ReactDOMFizzServer.renderToPipeableStream(
@@ -5732,9 +5731,7 @@ describe('ReactDOMFizzServer', () => {
           pipe(writable);
         });
       }).toErrorDev([
-        'React expects the `children` prop of <title> tags to be a string, number' +
-          gate(flags => (flags.enableBigIntSupport ? ', bigint' : '')) +
-          ', or object with a novel `toString` method but found an Array with length 2 instead. Browsers treat all child Nodes of <title> tags as Text content and React expects to be able to convert `children` of <title> tags to a single string value which is why Arrays of length greater than 1 are not supported. When using JSX it can be commong to combine text nodes and value nodes. For example: <title>hello {nameOfUser}</title>. While not immediately apparent, `children` in this case is an Array with length 2. If your `children` prop is using this form try rewriting it using a template string: <title>{`hello ${nameOfUser}`}</title>.',
+        'React expects the `children` prop of <title> tags to be a string, number, bigint, or object with a novel `toString` method but found an Array with length 2 instead. Browsers treat all child Nodes of <title> tags as Text content and React expects to be able to convert `children` of <title> tags to a single string value which is why Arrays of length greater than 1 are not supported. When using JSX it can be commong to combine text nodes and value nodes. For example: <title>hello {nameOfUser}</title>. While not immediately apparent, `children` in this case is an Array with length 2. If your `children` prop is using this form try rewriting it using a template string: <title>{`hello ${nameOfUser}`}</title>.',
       ]);
 
       expect(getVisibleChildren(document.head)).toEqual(<title />);
@@ -5771,9 +5768,7 @@ describe('ReactDOMFizzServer', () => {
           pipe(writable);
         });
       }).toErrorDev([
-        'React expects the `children` prop of <title> tags to be a string, number' +
-          gate(flags => (flags.enableBigIntSupport ? ', bigint' : '')) +
-          ', or object with a novel `toString` method but found an object that appears to be a React element which never implements a suitable `toString` method. Browsers treat all child Nodes of <title> tags as Text content and React expects to be able to convert children of <title> tags to a single string value which is why rendering React elements is not supported. If the `children` of <title> is a React Component try moving the <title> tag into that component. If the `children` of <title> is some HTML markup change it to be Text only to be valid HTML.',
+        'React expects the `children` prop of <title> tags to be a string, number, bigint, or object with a novel `toString` method but found an object that appears to be a React element which never implements a suitable `toString` method. Browsers treat all child Nodes of <title> tags as Text content and React expects to be able to convert children of <title> tags to a single string value which is why rendering React elements is not supported. If the `children` of <title> is a React Component try moving the <title> tag into that component. If the `children` of <title> is some HTML markup change it to be Text only to be valid HTML.',
       ]);
       // object titles are toStringed when float is on
       expect(getVisibleChildren(document.head)).toEqual(
@@ -5808,9 +5803,7 @@ describe('ReactDOMFizzServer', () => {
           pipe(writable);
         });
       }).toErrorDev([
-        'React expects the `children` prop of <title> tags to be a string, number' +
-          gate(flags => (flags.enableBigIntSupport ? ', bigint' : '')) +
-          ', or object with a novel `toString` method but found an object that does not implement a suitable `toString` method. Browsers treat all child Nodes of <title> tags as Text content and React expects to be able to convert children of <title> tags to a single string value. Using the default `toString` method available on every object is almost certainly an error. Consider whether the `children` of this <title> is an object in error and change it to a string or number value if so. Otherwise implement a `toString` method that React can use to produce a valid <title>.',
+        'React expects the `children` prop of <title> tags to be a string, number, bigint, or object with a novel `toString` method but found an object that does not implement a suitable `toString` method. Browsers treat all child Nodes of <title> tags as Text content and React expects to be able to convert children of <title> tags to a single string value. Using the default `toString` method available on every object is almost certainly an error. Consider whether the `children` of this <title> is an object in error and change it to a string or number value if so. Otherwise implement a `toString` method that React can use to produce a valid <title>.',
       ]);
       // object titles are toStringed when float is on
       expect(getVisibleChildren(document.head)).toEqual(
diff --git a/packages/react-dom/src/__tests__/ReactDOMInput-test.js b/packages/react-dom/src/__tests__/ReactDOMInput-test.js
index f817ede5214c..8b0dd3274d71 100644
--- a/packages/react-dom/src/__tests__/ReactDOMInput-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMInput-test.js
@@ -846,7 +846,6 @@ describe('ReactDOMInput', () => {
     expect(node.value).toBe('0');
   });
 
-  // @gate enableBigIntSupport
   it('should display `value` of bigint 5', async () => {
     await act(() => {
       root.render(<input type="text" value={5n} onChange={emptyFunction} />);
diff --git a/packages/react-dom/src/__tests__/ReactDOMOption-test.js b/packages/react-dom/src/__tests__/ReactDOMOption-test.js
index 8743c5993ddb..1661a98b1a69 100644
--- a/packages/react-dom/src/__tests__/ReactDOMOption-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMOption-test.js
@@ -171,7 +171,6 @@ describe('ReactDOMOption', () => {
     expect(container.firstChild.value).toBe('hello');
   });
 
-  // @gate enableBigIntSupport
   it('should support bigint values', async () => {
     const container = await renderIntoDocument(<option>{5n}</option>);
     expect(container.firstChild.innerHTML).toBe('5');
diff --git a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationBasic-test.js b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationBasic-test.js
index 266bae3d5eea..6323fe9b60c0 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationBasic-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationBasic-test.js
@@ -74,12 +74,8 @@ describe('ReactDOMServerIntegration', () => {
 
     itRenders('a bigint', async render => {
       const e = await render(42n);
-      if (gate(flags => flags.enableBigIntSupport)) {
-        expect(e.nodeType).toBe(3);
-        expect(e.nodeValue).toMatch('42');
-      } else {
-        expect(e).toBe(null);
-      }
+      expect(e.nodeType).toBe(3);
+      expect(e.nodeValue).toMatch('42');
     });
 
     itRenders('an array with one child', async render => {
diff --git a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationInput-test.js b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationInput-test.js
index 9f16ed58a761..7066aea04baf 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationInput-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationInput-test.js
@@ -32,8 +32,7 @@ function initModules() {
   };
 }
 
-const {resetModules, itRenders, serverRender, streamRender} =
-  ReactDOMServerIntegrationUtils(initModules);
+const {resetModules, itRenders} = ReactDOMServerIntegrationUtils(initModules);
 
 // TODO: Run this in React Fire mode after we figure out the SSR behavior.
 const desc = disableInputAttributeSyncing ? xdescribe : describe;
@@ -49,13 +48,7 @@ desc('ReactDOMServerIntegrationInput', () => {
 
   itRenders('an input with a bigint value and an onChange', async render => {
     const e = await render(<input value={5n} onChange={() => {}} />);
-    expect(e.value).toBe(
-      gate(flags => flags.enableBigIntSupport) ||
-        render === serverRender ||
-        render === streamRender
-        ? '5'
-        : '',
-    );
+    expect(e.value).toBe('5');
   });
 
   itRenders('an input with a value and readOnly', async render => {
diff --git a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationSelect-test.js b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationSelect-test.js
index 9b20b1edcd21..664914a43668 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationSelect-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationSelect-test.js
@@ -224,9 +224,7 @@ describe('ReactDOMServerIntegrationSelect', () => {
       </select>,
     );
     const option = e.options[0];
-    expect(option.textContent).toBe(
-      gate(flags => flags.enableBigIntSupport) ? 'A B 5' : 'A B ',
-    );
+    expect(option.textContent).toBe('A B 5');
     expect(option.value).toBe('bar');
     expect(option.selected).toBe(true);
   });
diff --git a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationTextarea-test.js b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationTextarea-test.js
index 79b5fd840d88..9ce04840dbb0 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationTextarea-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationTextarea-test.js
@@ -30,8 +30,7 @@ function initModules() {
   };
 }
 
-const {resetModules, itRenders, serverRender, streamRender} =
-  ReactDOMServerIntegrationUtils(initModules);
+const {resetModules, itRenders} = ReactDOMServerIntegrationUtils(initModules);
 
 describe('ReactDOMServerIntegrationTextarea', () => {
   beforeEach(() => {
@@ -51,13 +50,7 @@ describe('ReactDOMServerIntegrationTextarea', () => {
   itRenders('a textarea with a bigint value and an onChange', async render => {
     const e = await render(<textarea value={5n} onChange={() => {}} />);
     expect(e.getAttribute('value')).toBe(null);
-    expect(e.value).toBe(
-      gate(flags => flags.enableBigIntSupport) ||
-        render === serverRender ||
-        render === streamRender
-        ? '5'
-        : '',
-    );
+    expect(e.value).toBe('5');
   });
 
   itRenders('a textarea with a value of undefined', async render => {
diff --git a/packages/react-dom/src/__tests__/ReactDOMTextarea-test.js b/packages/react-dom/src/__tests__/ReactDOMTextarea-test.js
index 134e019c6b65..db7cb1bf6268 100644
--- a/packages/react-dom/src/__tests__/ReactDOMTextarea-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMTextarea-test.js
@@ -80,7 +80,6 @@ describe('ReactDOMTextarea', () => {
     expect(node.value).toBe('0');
   });
 
-  // @gate enableBigIntSupport
   it('should display `defaultValue` of bigint 0', async () => {
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
diff --git a/packages/react-dom/src/__tests__/ReactMultiChildText-test.js b/packages/react-dom/src/__tests__/ReactMultiChildText-test.js
index 7cf2c048c504..c9c45e2d0ed0 100644
--- a/packages/react-dom/src/__tests__/ReactMultiChildText-test.js
+++ b/packages/react-dom/src/__tests__/ReactMultiChildText-test.js
@@ -174,7 +174,6 @@ describe('ReactMultiChildText', () => {
     ]);
   });
 
-  // @gate enableBigIntSupport
   it('should correctly handle bigint children for render and update', async () => {
     // prettier-ignore
     await testAllPermutations([
diff --git a/packages/react-reconciler/src/ReactChildFiber.js b/packages/react-reconciler/src/ReactChildFiber.js
index 956af89af076..dde892c5893e 100644
--- a/packages/react-reconciler/src/ReactChildFiber.js
+++ b/packages/react-reconciler/src/ReactChildFiber.js
@@ -25,7 +25,6 @@ import {
   Forked,
   PlacementDEV,
 } from './ReactFiberFlags';
-import {enableBigIntSupport} from 'shared/ReactFeatureFlags';
 import {
   getIteratorFn,
   REACT_ELEMENT_TYPE,
@@ -658,7 +657,7 @@ function createChildReconciler(
     if (
       (typeof newChild === 'string' && newChild !== '') ||
       typeof newChild === 'number' ||
-      (enableBigIntSupport && typeof newChild === 'bigint')
+      typeof newChild === 'bigint'
     ) {
       // Text nodes don't have keys. If the previous node is implicitly keyed
       // we can continue to replace it without aborting even if it is not a text
@@ -780,7 +779,7 @@ function createChildReconciler(
     if (
       (typeof newChild === 'string' && newChild !== '') ||
       typeof newChild === 'number' ||
-      (enableBigIntSupport && typeof newChild === 'bigint')
+      typeof newChild === 'bigint'
     ) {
       // Text nodes don't have keys. If the previous node is implicitly keyed
       // we can continue to replace it without aborting even if it is not a text
@@ -905,7 +904,7 @@ function createChildReconciler(
     if (
       (typeof newChild === 'string' && newChild !== '') ||
       typeof newChild === 'number' ||
-      (enableBigIntSupport && typeof newChild === 'bigint')
+      typeof newChild === 'bigint'
     ) {
       // Text nodes don't have keys, so we neither have to check the old nor
       // new node for the key. If both are text nodes, they match.
@@ -1722,7 +1721,7 @@ function createChildReconciler(
     if (
       (typeof newChild === 'string' && newChild !== '') ||
       typeof newChild === 'number' ||
-      (enableBigIntSupport && typeof newChild === 'bigint')
+      typeof newChild === 'bigint'
     ) {
       return placeSingleChild(
         reconcileSingleTextNode(
diff --git a/packages/react-reconciler/src/__tests__/ReactTopLevelText-test.js b/packages/react-reconciler/src/__tests__/ReactTopLevelText-test.js
index 9c5de7bd2ee5..b1d8dd5e0108 100644
--- a/packages/react-reconciler/src/__tests__/ReactTopLevelText-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactTopLevelText-test.js
@@ -40,7 +40,6 @@ describe('ReactTopLevelText', () => {
     expect(ReactNoop).toMatchRenderedOutput('10');
   });
 
-  // @gate enableBigIntSupport
   it('should render a component returning bigints directly from render', async () => {
     const Text = ({value}) => value;
     ReactNoop.render(<Text value={10n} />);
diff --git a/packages/react-server/src/ReactFizzServer.js b/packages/react-server/src/ReactFizzServer.js
index a06ef06e8bb2..7d5659981e40 100644
--- a/packages/react-server/src/ReactFizzServer.js
+++ b/packages/react-server/src/ReactFizzServer.js
@@ -137,7 +137,6 @@ import {
 import ReactSharedInternals from 'shared/ReactSharedInternals';
 import {
   disableLegacyContext,
-  enableBigIntSupport,
   enableScopeAPI,
   enableSuspenseAvoidThisFallbackFizz,
   enableCache,
@@ -2323,10 +2322,7 @@ function renderNodeDestructive(
     return;
   }
 
-  if (
-    typeof node === 'number' ||
-    (enableBigIntSupport && typeof node === 'bigint')
-  ) {
+  if (typeof node === 'number' || typeof node === 'bigint') {
     const segment = task.blockedSegment;
     if (segment === null) {
       // We assume a text node doesn't have a representation in the replay set,
diff --git a/packages/react/src/ReactChildren.js b/packages/react/src/ReactChildren.js
index d3c155dc8be7..d671c1503327 100644
--- a/packages/react/src/ReactChildren.js
+++ b/packages/react/src/ReactChildren.js
@@ -16,7 +16,6 @@ import type {
 } from 'shared/ReactTypes';
 
 import isArray from 'shared/isArray';
-import {enableBigIntSupport} from 'shared/ReactFeatureFlags';
 import {
   getIteratorFn,
   REACT_ELEMENT_TYPE,
@@ -165,10 +164,6 @@ function mapIntoArray(
   } else {
     switch (type) {
       case 'bigint':
-        if (!enableBigIntSupport) {
-          break;
-        }
-      // fallthrough for enabled BigInt support
       case 'string':
       case 'number':
         invokeCallback = true;
diff --git a/packages/react/src/__tests__/ReactChildren-test.js b/packages/react/src/__tests__/ReactChildren-test.js
index 062794d31691..92e7ba435a1d 100644
--- a/packages/react/src/__tests__/ReactChildren-test.js
+++ b/packages/react/src/__tests__/ReactChildren-test.js
@@ -188,9 +188,7 @@ describe('ReactChildren', () => {
     );
 
     function assertCalls() {
-      expect(callback).toHaveBeenCalledTimes(
-        gate(flags => flags.enableBigIntSupport) ? 10 : 9,
-      );
+      expect(callback).toHaveBeenCalledTimes(10);
       expect(callback).toHaveBeenCalledWith(div, 0);
       expect(callback).toHaveBeenCalledWith(span, 1);
       expect(callback).toHaveBeenCalledWith(a, 2);
@@ -200,11 +198,7 @@ describe('ReactChildren', () => {
       expect(callback).toHaveBeenCalledWith(null, 6);
       expect(callback).toHaveBeenCalledWith(null, 7);
       expect(callback).toHaveBeenCalledWith(null, 8);
-      if (gate(flags => flags.enableBigIntSupport)) {
-        expect(callback).toHaveBeenCalledWith(9n, 9);
-      } else {
-        expect(callback).not.toHaveBeenCalledWith(9n, 9);
-      }
+      expect(callback).toHaveBeenCalledWith(9n, 9);
       callback.mockClear();
     }
 
@@ -217,24 +211,14 @@ describe('ReactChildren', () => {
       context,
     );
     assertCalls();
-    expect(mappedChildren).toEqual(
-      gate(flags => flags.enableBigIntSupport)
-        ? [
-            <div key=".$divNode" />,
-            <span key=".1:0:$spanNode" />,
-            <a key=".2:$aNode" />,
-            'string',
-            1234,
-            9n,
-          ]
-        : [
-            <div key=".$divNode" />,
-            <span key=".1:0:$spanNode" />,
-            <a key=".2:$aNode" />,
-            'string',
-            1234,
-          ],
-    );
+    expect(mappedChildren).toEqual([
+      <div key=".$divNode" />,
+      <span key=".1:0:$spanNode" />,
+      <a key=".2:$aNode" />,
+      'string',
+      1234,
+      9n,
+    ]);
   });
 
   it('should be called for each child in nested structure', () => {
diff --git a/packages/shared/ReactFeatureFlags.js b/packages/shared/ReactFeatureFlags.js
index 5100868b96aa..a55e86480645 100644
--- a/packages/shared/ReactFeatureFlags.js
+++ b/packages/shared/ReactFeatureFlags.js
@@ -161,8 +161,6 @@ export const disableClientCache = false;
 // Changes Server Components Reconciliation when they have keys
 export const enableServerComponentKeys = true;
 
-export const enableBigIntSupport = true;
-
 /**
  * Enables a new error detection for infinite render loops from updates caused
  * by setState or similar outside of the component owning the state.
diff --git a/packages/shared/forks/ReactFeatureFlags.native-fb-dynamic.js b/packages/shared/forks/ReactFeatureFlags.native-fb-dynamic.js
index be82df80b821..2dfb0f2bd2a0 100644
--- a/packages/shared/forks/ReactFeatureFlags.native-fb-dynamic.js
+++ b/packages/shared/forks/ReactFeatureFlags.native-fb-dynamic.js
@@ -20,7 +20,6 @@
 export const alwaysThrottleRetries = __VARIANT__;
 export const consoleManagedByDevToolsDuringStrictMode = __VARIANT__;
 export const enableAsyncActions = __VARIANT__;
-export const enableBigIntSupport = __VARIANT__;
 export const enableComponentStackLocations = __VARIANT__;
 export const enableDeferRootSchedulingToMicrotask = __VARIANT__;
 export const enableInfiniteRenderLoopDetection = __VARIANT__;
diff --git a/packages/shared/forks/ReactFeatureFlags.native-fb.js b/packages/shared/forks/ReactFeatureFlags.native-fb.js
index 1a5636531feb..62b554010caa 100644
--- a/packages/shared/forks/ReactFeatureFlags.native-fb.js
+++ b/packages/shared/forks/ReactFeatureFlags.native-fb.js
@@ -22,7 +22,6 @@ export const {
   alwaysThrottleRetries,
   consoleManagedByDevToolsDuringStrictMode,
   enableAsyncActions,
-  enableBigIntSupport,
   enableComponentStackLocations,
   enableDeferRootSchedulingToMicrotask,
   enableInfiniteRenderLoopDetection,
diff --git a/packages/shared/forks/ReactFeatureFlags.native-oss.js b/packages/shared/forks/ReactFeatureFlags.native-oss.js
index 4287a6afba3e..f89969af59b9 100644
--- a/packages/shared/forks/ReactFeatureFlags.native-oss.js
+++ b/packages/shared/forks/ReactFeatureFlags.native-oss.js
@@ -22,7 +22,6 @@ export const enableRefAsProp = __TODO_NEXT_RN_MAJOR__;
 export const disableStringRefs = __TODO_NEXT_RN_MAJOR__;
 export const disableLegacyMode = __TODO_NEXT_RN_MAJOR__;
 export const disableDOMTestUtils = __TODO_NEXT_RN_MAJOR__;
-export const enableBigIntSupport = __TODO_NEXT_RN_MAJOR__;
 export const useModernStrictMode = __TODO_NEXT_RN_MAJOR__;
 export const enableReactTestRendererWarning = __TODO_NEXT_RN_MAJOR__;
 export const enableAsyncActions = __TODO_NEXT_RN_MAJOR__;
diff --git a/packages/shared/forks/ReactFeatureFlags.test-renderer.js b/packages/shared/forks/ReactFeatureFlags.test-renderer.js
index 2c3db195ac7d..f93977ed1925 100644
--- a/packages/shared/forks/ReactFeatureFlags.test-renderer.js
+++ b/packages/shared/forks/ReactFeatureFlags.test-renderer.js
@@ -87,7 +87,6 @@ export const enableInfiniteRenderLoopDetection = false;
 // const __NEXT_MAJOR__ = __EXPERIMENTAL__;
 export const enableRefAsProp = true;
 export const disableStringRefs = true;
-export const enableBigIntSupport = true;
 export const disableLegacyMode = true;
 export const disableLegacyContext = true;
 export const disableDOMTestUtils = true;
diff --git a/packages/shared/forks/ReactFeatureFlags.test-renderer.native-fb.js b/packages/shared/forks/ReactFeatureFlags.test-renderer.native-fb.js
index 4a860268d035..2b85343516ab 100644
--- a/packages/shared/forks/ReactFeatureFlags.test-renderer.native-fb.js
+++ b/packages/shared/forks/ReactFeatureFlags.test-renderer.native-fb.js
@@ -86,7 +86,5 @@ export const enableReactTestRendererWarning = false;
 export const disableLegacyMode = false;
 export const disableDOMTestUtils = false;
 
-export const enableBigIntSupport = false;
-
 // Flow magic to verify the exports of this file match the original version.
 ((((null: any): ExportsType): FeatureFlagsType): ExportsType);
diff --git a/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js b/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js
index 9f95dacd7ab6..9a757423fe7d 100644
--- a/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js
+++ b/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js
@@ -87,7 +87,5 @@ export const enableReactTestRendererWarning = false;
 export const disableLegacyMode = false;
 export const disableDOMTestUtils = false;
 
-export const enableBigIntSupport = true;
-
 // Flow magic to verify the exports of this file match the original version.
 ((((null: any): ExportsType): FeatureFlagsType): ExportsType);
diff --git a/packages/shared/forks/ReactFeatureFlags.www-dynamic.js b/packages/shared/forks/ReactFeatureFlags.www-dynamic.js
index 552a588ad64f..96921a847d93 100644
--- a/packages/shared/forks/ReactFeatureFlags.www-dynamic.js
+++ b/packages/shared/forks/ReactFeatureFlags.www-dynamic.js
@@ -14,7 +14,6 @@
 // with the __VARIANT__ set to `true`, and once set to `false`.
 
 export const disableIEWorkarounds = __VARIANT__;
-export const enableBigIntSupport = __VARIANT__;
 export const enableUseRefAccessWarning = __VARIANT__;
 export const disableSchedulerTimeoutInWorkLoop = __VARIANT__;
 export const enableLazyContextPropagation = __VARIANT__;
diff --git a/packages/shared/forks/ReactFeatureFlags.www.js b/packages/shared/forks/ReactFeatureFlags.www.js
index ef7a207974cf..39fcd219eae3 100644
--- a/packages/shared/forks/ReactFeatureFlags.www.js
+++ b/packages/shared/forks/ReactFeatureFlags.www.js
@@ -16,7 +16,6 @@ const dynamicFeatureFlags: DynamicFeatureFlags = require('ReactFeatureFlags');
 
 export const {
   disableIEWorkarounds,
-  enableBigIntSupport,
   enableTrustedTypesIntegration,
   enableDebugTracing,
   enableUseRefAccessWarning,