diff --git a/compiler/packages/babel-plugin-react-compiler/src/ReactiveScopes/PruneHoistedContexts.ts b/compiler/packages/babel-plugin-react-compiler/src/ReactiveScopes/PruneHoistedContexts.ts
index 66b1e1ce152b9..ae3ff122a23a2 100644
--- a/compiler/packages/babel-plugin-react-compiler/src/ReactiveScopes/PruneHoistedContexts.ts
+++ b/compiler/packages/babel-plugin-react-compiler/src/ReactiveScopes/PruneHoistedContexts.ts
@@ -5,10 +5,13 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+import {CompilerError} from '..';
 import {
   convertHoistedLValueKind,
   IdentifierId,
+  InstructionId,
   InstructionKind,
+  Place,
   ReactiveFunction,
   ReactiveInstruction,
   ReactiveScopeBlock,
@@ -24,15 +27,38 @@ import {
 /*
  * Prunes DeclareContexts lowered for HoistedConsts, and transforms any references back to its
  * original instruction kind.
+ *
+ * Also detects and bails out on context variables which are:
+ * - function declarations, which are hoisted by JS engines to the nearest block scope
+ * - referenced before they are defined (i.e. having a `DeclareContext HoistedConst`)
+ * - declared
+ *
+ * This is because React Compiler converts a `function foo()` function declaration to
+ * 1. a `let foo;` declaration before reactive memo blocks
+ * 2. a `foo = function foo() {}` assignment within the block
+ *
+ * This means references before the assignment are invalid (see fixture
+ * error.todo-functiondecl-hoisting)
  */
 export function pruneHoistedContexts(fn: ReactiveFunction): void {
   visitReactiveFunction(fn, new Visitor(), {
     activeScopes: empty(),
+    uninitialized: new Map(),
   });
 }
 
 type VisitorState = {
   activeScopes: Stack<Set<IdentifierId>>;
+  uninitialized: Map<
+    IdentifierId,
+    | {
+        kind: 'unknown-kind';
+      }
+    | {
+        kind: 'func';
+        definition: Place | null;
+      }
+  >;
 };
 
 class Visitor extends ReactiveFunctionTransform<VisitorState> {
@@ -40,15 +66,39 @@ class Visitor extends ReactiveFunctionTransform<VisitorState> {
     state.activeScopes = state.activeScopes.push(
       new Set(scope.scope.declarations.keys()),
     );
+    /**
+     * Add declared but not initialized / assigned variables. This may include
+     * function declarations that escape the memo block.
+     */
+    for (const decl of scope.scope.declarations.values()) {
+      state.uninitialized.set(decl.identifier.id, {kind: 'unknown-kind'});
+    }
     this.traverseScope(scope, state);
     state.activeScopes.pop();
+    for (const decl of scope.scope.declarations.values()) {
+      state.uninitialized.delete(decl.identifier.id);
+    }
+  }
+  override visitPlace(
+    _id: InstructionId,
+    place: Place,
+    state: VisitorState,
+  ): void {
+    const maybeHoistedFn = state.uninitialized.get(place.identifier.id);
+    if (
+      maybeHoistedFn?.kind === 'func' &&
+      maybeHoistedFn.definition !== place
+    ) {
+      CompilerError.throwTodo({
+        reason: '[PruneHoistedContexts] Rewrite hoisted function references',
+        loc: place.loc,
+      });
+    }
   }
   override transformInstruction(
     instruction: ReactiveInstruction,
     state: VisitorState,
   ): Transformed<ReactiveStatement> {
-    this.visitInstruction(instruction, state);
-
     /**
      * Remove hoisted declarations to preserve TDZ
      */
@@ -57,6 +107,18 @@ class Visitor extends ReactiveFunctionTransform<VisitorState> {
         instruction.value.lvalue.kind,
       );
       if (maybeNonHoisted != null) {
+        if (
+          maybeNonHoisted === InstructionKind.Function &&
+          state.uninitialized.has(instruction.value.lvalue.place.identifier.id)
+        ) {
+          state.uninitialized.set(
+            instruction.value.lvalue.place.identifier.id,
+            {
+              kind: 'func',
+              definition: null,
+            },
+          );
+        }
         return {kind: 'remove'};
       }
     }
@@ -65,7 +127,7 @@ class Visitor extends ReactiveFunctionTransform<VisitorState> {
       instruction.value.lvalue.kind !== InstructionKind.Reassign
     ) {
       /**
-       * Rewrite StoreContexts let/const/functions that will be pre-declared in
+       * Rewrite StoreContexts let/const that will be pre-declared in
        * codegen to reassignments.
        */
       const lvalueId = instruction.value.lvalue.place.identifier.id;
@@ -73,10 +135,36 @@ class Visitor extends ReactiveFunctionTransform<VisitorState> {
         scope.has(lvalueId),
       );
       if (isDeclaredByScope) {
-        instruction.value.lvalue.kind = InstructionKind.Reassign;
+        if (
+          instruction.value.lvalue.kind === InstructionKind.Let ||
+          instruction.value.lvalue.kind === InstructionKind.Const
+        ) {
+          instruction.value.lvalue.kind = InstructionKind.Reassign;
+        } else if (instruction.value.lvalue.kind === InstructionKind.Function) {
+          const maybeHoistedFn = state.uninitialized.get(lvalueId);
+          if (maybeHoistedFn != null) {
+            CompilerError.invariant(maybeHoistedFn.kind === 'func', {
+              reason: '[PruneHoistedContexts] Unexpected hoisted function',
+              loc: instruction.loc,
+            });
+            maybeHoistedFn.definition = instruction.value.lvalue.place;
+            /**
+             * References to hoisted functions are now "safe" as variable assignments
+             * have finished.
+             */
+            state.uninitialized.delete(lvalueId);
+          }
+        } else {
+          CompilerError.throwTodo({
+            reason: '[PruneHoistedContexts] Unexpected kind',
+            description: `(${instruction.value.lvalue.kind})`,
+            loc: instruction.loc,
+          });
+        }
       }
     }
 
+    this.visitInstruction(instruction, state);
     return {kind: 'keep'};
   }
 }
diff --git a/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/bug-functiondecl-hoisting.expect.md b/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/bug-functiondecl-hoisting.expect.md
deleted file mode 100644
index f8712ed7289a9..0000000000000
--- a/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/bug-functiondecl-hoisting.expect.md
+++ /dev/null
@@ -1,79 +0,0 @@
-
-## Input
-
-```javascript
-import {Stringify} from 'shared-runtime';
-
-/**
- * Fixture currently fails with
- * Found differences in evaluator results
- *   Non-forget (expected):
- *   (kind: ok) <div>{"result":{"value":2},"fn":{"kind":"Function","result":{"value":2}},"shouldInvokeFns":true}</div>
- *   Forget:
- *   (kind: exception) bar is not a function
- */
-function Foo({value}) {
-  const result = bar();
-  function bar() {
-    return {value};
-  }
-  return <Stringify result={result} fn={bar} shouldInvokeFns={true} />;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Foo,
-  params: [{value: 2}],
-};
-
-```
-
-## Code
-
-```javascript
-import { c as _c } from "react/compiler-runtime";
-import { Stringify } from "shared-runtime";
-
-/**
- * Fixture currently fails with
- * Found differences in evaluator results
- *   Non-forget (expected):
- *   (kind: ok) <div>{"result":{"value":2},"fn":{"kind":"Function","result":{"value":2}},"shouldInvokeFns":true}</div>
- *   Forget:
- *   (kind: exception) bar is not a function
- */
-function Foo(t0) {
-  const $ = _c(6);
-  const { value } = t0;
-  let bar;
-  let result;
-  if ($[0] !== value) {
-    result = bar();
-    bar = function bar() {
-      return { value };
-    };
-    $[0] = value;
-    $[1] = bar;
-    $[2] = result;
-  } else {
-    bar = $[1];
-    result = $[2];
-  }
-  let t1;
-  if ($[3] !== bar || $[4] !== result) {
-    t1 = <Stringify result={result} fn={bar} shouldInvokeFns={true} />;
-    $[3] = bar;
-    $[4] = result;
-    $[5] = t1;
-  } else {
-    t1 = $[5];
-  }
-  return t1;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Foo,
-  params: [{ value: 2 }],
-};
-
-```
-      
\ No newline at end of file
diff --git a/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-functiondecl-hoisting.expect.md b/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-functiondecl-hoisting.expect.md
new file mode 100644
index 0000000000000..6e2310bd1064c
--- /dev/null
+++ b/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-functiondecl-hoisting.expect.md
@@ -0,0 +1,43 @@
+
+## Input
+
+```javascript
+import {Stringify} from 'shared-runtime';
+
+/**
+ * Fixture currently fails with
+ * Found differences in evaluator results
+ *   Non-forget (expected):
+ *   (kind: ok) <div>{"result":{"value":2},"fn":{"kind":"Function","result":{"value":2}},"shouldInvokeFns":true}</div>
+ *   Forget:
+ *   (kind: exception) bar is not a function
+ */
+function Foo({value}) {
+  const result = bar();
+  function bar() {
+    return {value};
+  }
+  return <Stringify result={result} fn={bar} shouldInvokeFns={true} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Foo,
+  params: [{value: 2}],
+};
+
+```
+
+
+## Error
+
+```
+  10 |  */
+  11 | function Foo({value}) {
+> 12 |   const result = bar();
+     |                  ^^^ Todo: [PruneHoistedContexts] Rewrite hoisted function references (12:12)
+  13 |   function bar() {
+  14 |     return {value};
+  15 |   }
+```
+          
+      
\ No newline at end of file
diff --git a/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/bug-functiondecl-hoisting.tsx b/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-functiondecl-hoisting.tsx
similarity index 100%
rename from compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/bug-functiondecl-hoisting.tsx
rename to compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-functiondecl-hoisting.tsx
diff --git a/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-valid-functiondecl-hoisting.expect.md b/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-valid-functiondecl-hoisting.expect.md
new file mode 100644
index 0000000000000..fb8988c8f878d
--- /dev/null
+++ b/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-valid-functiondecl-hoisting.expect.md
@@ -0,0 +1,46 @@
+
+## Input
+
+```javascript
+import {Stringify} from 'shared-runtime';
+/**
+ * Also see error.todo-functiondecl-hoisting.tsx which shows *invalid*
+ * compilation cases.
+ *
+ * This bailout specifically is a false positive for since this function's only
+ * reference-before-definition are within other functions which are not invoked.
+ */
+function Foo() {
+  'use memo';
+
+  function foo() {
+    return bar();
+  }
+  function bar() {
+    return 42;
+  }
+
+  return <Stringify fn1={foo} fn2={bar} shouldInvokeFns={true} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Foo,
+  params: [],
+};
+
+```
+
+
+## Error
+
+```
+  13 |     return bar();
+  14 |   }
+> 15 |   function bar() {
+     |            ^^^ Todo: [PruneHoistedContexts] Rewrite hoisted function references (15:15)
+  16 |     return 42;
+  17 |   }
+  18 |
+```
+          
+      
\ No newline at end of file
diff --git a/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-valid-functiondecl-hoisting.tsx b/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-valid-functiondecl-hoisting.tsx
new file mode 100644
index 0000000000000..063492b89cf52
--- /dev/null
+++ b/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-valid-functiondecl-hoisting.tsx
@@ -0,0 +1,25 @@
+import {Stringify} from 'shared-runtime';
+/**
+ * Also see error.todo-functiondecl-hoisting.tsx which shows *invalid*
+ * compilation cases.
+ *
+ * This bailout specifically is a false positive for since this function's only
+ * reference-before-definition are within other functions which are not invoked.
+ */
+function Foo() {
+  'use memo';
+
+  function foo() {
+    return bar();
+  }
+  function bar() {
+    return 42;
+  }
+
+  return <Stringify fn1={foo} fn2={bar} shouldInvokeFns={true} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Foo,
+  params: [],
+};
diff --git a/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/fbt/error.todo-fbt-param-nested-fbt.expect.md b/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/fbt/error.todo-fbt-param-nested-fbt.expect.md
new file mode 100644
index 0000000000000..eb8073282efa1
--- /dev/null
+++ b/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/fbt/error.todo-fbt-param-nested-fbt.expect.md
@@ -0,0 +1,56 @@
+
+## Input
+
+```javascript
+import fbt from 'fbt';
+import {Stringify} from 'shared-runtime';
+
+/**
+ * MemoizeFbtAndMacroOperands needs to account for nested fbt calls.
+ * Expected fixture `fbt-param-call-arguments` to succeed but it failed with error:
+ *   /fbt-param-call-arguments.ts: Line 19 Column 11: fbt: unsupported babel node: Identifier
+ *   ---
+ *   t3
+ *   ---
+ */
+function Component({firstname, lastname}) {
+  'use memo';
+  return (
+    <Stringify>
+      {fbt(
+        [
+          'Name: ',
+          fbt.param('firstname', <Stringify key={0} name={firstname} />),
+          ', ',
+          fbt.param(
+            'lastname',
+            <Stringify key={0} name={lastname}>
+              {fbt('(inner fbt)', 'Inner fbt value')}
+            </Stringify>
+          ),
+        ],
+        'Name'
+      )}
+    </Stringify>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{firstname: 'first', lastname: 'last'}],
+  sequentialRenders: [{firstname: 'first', lastname: 'last'}],
+};
+
+```
+
+
+## Error
+
+```
+Line 19 Column 11: fbt: unsupported babel node: Identifier
+---
+t3
+---
+```
+          
+      
\ No newline at end of file
diff --git a/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/fbt/error.todo-fbt-param-nested-fbt.js b/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/fbt/error.todo-fbt-param-nested-fbt.js
new file mode 100644
index 0000000000000..14e3278e395de
--- /dev/null
+++ b/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/fbt/error.todo-fbt-param-nested-fbt.js
@@ -0,0 +1,38 @@
+import fbt from 'fbt';
+import {Stringify} from 'shared-runtime';
+
+/**
+ * MemoizeFbtAndMacroOperands needs to account for nested fbt calls.
+ * Expected fixture `fbt-param-call-arguments` to succeed but it failed with error:
+ *   /fbt-param-call-arguments.ts: Line 19 Column 11: fbt: unsupported babel node: Identifier
+ *   ---
+ *   t3
+ *   ---
+ */
+function Component({firstname, lastname}) {
+  'use memo';
+  return (
+    <Stringify>
+      {fbt(
+        [
+          'Name: ',
+          fbt.param('firstname', <Stringify key={0} name={firstname} />),
+          ', ',
+          fbt.param(
+            'lastname',
+            <Stringify key={0} name={lastname}>
+              {fbt('(inner fbt)', 'Inner fbt value')}
+            </Stringify>
+          ),
+        ],
+        'Name'
+      )}
+    </Stringify>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{firstname: 'first', lastname: 'last'}],
+  sequentialRenders: [{firstname: 'first', lastname: 'last'}],
+};
diff --git a/packages/eslint-plugin-react-hooks/src/rules/RulesOfHooks.ts b/packages/eslint-plugin-react-hooks/src/rules/RulesOfHooks.ts
index 6be40df53226a..ac7d0f3a06cfe 100644
--- a/packages/eslint-plugin-react-hooks/src/rules/RulesOfHooks.ts
+++ b/packages/eslint-plugin-react-hooks/src/rules/RulesOfHooks.ts
@@ -128,7 +128,7 @@ const rule = {
     docs: {
       description: 'enforces the Rules of Hooks',
       recommended: true,
-      url: 'https://reactjs.org/docs/hooks-rules.html',
+      url: 'https://react.dev/reference/rules/rules-of-hooks',
     },
   },
   create(context: Rule.RuleContext) {
diff --git a/packages/react-native-renderer/src/ReactFiberConfigFabric.js b/packages/react-native-renderer/src/ReactFiberConfigFabric.js
index 1cf98193abcc7..afa0a9c218e53 100644
--- a/packages/react-native-renderer/src/ReactFiberConfigFabric.js
+++ b/packages/react-native-renderer/src/ReactFiberConfigFabric.js
@@ -63,7 +63,6 @@ import {
 } from './ReactNativeFiberInspector';
 
 import {
-  enableFabricCompleteRootInCommitPhase,
   passChildrenWhenCloningPersistedNodes,
   enableLazyPublicInstanceInFabric,
 } from 'shared/ReactFeatureFlags';
@@ -543,19 +542,14 @@ export function finalizeContainerChildren(
   container: Container,
   newChildren: ChildSet,
 ): void {
-  if (!enableFabricCompleteRootInCommitPhase) {
-    completeRoot(container.containerTag, newChildren);
-  }
+  // Noop - children will be replaced in replaceContainerChildren
 }
 
 export function replaceContainerChildren(
   container: Container,
   newChildren: ChildSet,
 ): void {
-  // Noop - children will be replaced in finalizeContainerChildren
-  if (enableFabricCompleteRootInCommitPhase) {
-    completeRoot(container.containerTag, newChildren);
-  }
+  completeRoot(container.containerTag, newChildren);
 }
 
 export {getClosestInstanceFromNode as getInstanceFromNode};
diff --git a/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMEdge-test.js b/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMEdge-test.js
index 5194913d2cb32..a4418b701716a 100644
--- a/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMEdge-test.js
+++ b/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMEdge-test.js
@@ -692,6 +692,44 @@ describe('ReactFlightDOMEdge', () => {
     expect(html).toBe(html2);
   });
 
+  it('regression: should not leak serialized size', async () => {
+    const MAX_ROW_SIZE = 3200;
+    // This test case is a bit convoluted and may no longer trigger the original bug.
+    // Originally, the size of `promisedText` was not cleaned up so the sync portion
+    // ended up being deferred immediately when we called `renderToReadableStream` again
+    // i.e. `result2.syncText` became a Lazy element on the second request.
+    const longText = 'd'.repeat(MAX_ROW_SIZE);
+    const promisedText = Promise.resolve(longText);
+    const model = {syncText: <p>{longText}</p>, promisedText};
+
+    const stream = await serverAct(() =>
+      ReactServerDOMServer.renderToReadableStream(model),
+    );
+
+    const result = await ReactServerDOMClient.createFromReadableStream(stream, {
+      serverConsumerManifest: {
+        moduleMap: null,
+        moduleLoading: null,
+      },
+    });
+
+    const stream2 = await serverAct(() =>
+      ReactServerDOMServer.renderToReadableStream(model),
+    );
+
+    const result2 = await ReactServerDOMClient.createFromReadableStream(
+      stream2,
+      {
+        serverConsumerManifest: {
+          moduleMap: null,
+          moduleLoading: null,
+        },
+      },
+    );
+
+    expect(result2.syncText).toEqual(result.syncText);
+  });
+
   it('should be able to serialize any kind of typed array', async () => {
     const buffer = new Uint8Array([
       123, 4, 10, 5, 100, 255, 244, 45, 56, 67, 43, 124, 67, 89, 100, 20,
diff --git a/packages/react-server/src/ReactFlightServer.js b/packages/react-server/src/ReactFlightServer.js
index aefcf5f6ee809..98b17cc92088e 100644
--- a/packages/react-server/src/ReactFlightServer.js
+++ b/packages/react-server/src/ReactFlightServer.js
@@ -2302,6 +2302,9 @@ function renderModel(
   key: string,
   value: ReactClientValue,
 ): ReactJSONValue {
+  // First time we're serializing the key, we should add it to the size.
+  serializedSize += key.length;
+
   const prevKeyPath = task.keyPath;
   const prevImplicitSlot = task.implicitSlot;
   try {
@@ -2416,8 +2419,6 @@ function renderModelDestructive(
   // Set the currently rendering model
   task.model = value;
 
-  serializedSize += parentPropertyName.length;
-
   // Special Symbol, that's very common.
   if (value === REACT_ELEMENT_TYPE) {
     return '$';
@@ -3926,18 +3927,9 @@ function emitChunk(
     return;
   }
   // For anything else we need to try to serialize it using JSON.
-  // We stash the outer parent size so we can restore it when we exit.
-  const parentSerializedSize = serializedSize;
-  // We don't reset the serialized size counter from reentry because that indicates that we
-  // are outlining a model and we actually want to include that size into the parent since
-  // it will still block the parent row. It only restores to zero at the top of the stack.
-  try {
-    // $FlowFixMe[incompatible-type] stringify can return null for undefined but we never do
-    const json: string = stringify(value, task.toJSON);
-    emitModelChunk(request, task.id, json);
-  } finally {
-    serializedSize = parentSerializedSize;
-  }
+  // $FlowFixMe[incompatible-type] stringify can return null for undefined but we never do
+  const json: string = stringify(value, task.toJSON);
+  emitModelChunk(request, task.id, json);
 }
 
 function erroredTask(request: Request, task: Task, error: mixed): void {
@@ -3975,6 +3967,11 @@ function retryTask(request: Request, task: Task): void {
   const prevDebugID = debugID;
   task.status = RENDERING;
 
+  // We stash the outer parent size so we can restore it when we exit.
+  const parentSerializedSize = serializedSize;
+  // We don't reset the serialized size counter from reentry because that indicates that we
+  // are outlining a model and we actually want to include that size into the parent since
+  // it will still block the parent row. It only restores to zero at the top of the stack.
   try {
     // Track the root so we know that we have to emit this object even though it
     // already has an ID. This is needed because we might see this object twice
@@ -4086,6 +4083,7 @@ function retryTask(request: Request, task: Task): void {
     if (__DEV__) {
       debugID = prevDebugID;
     }
+    serializedSize = parentSerializedSize;
   }
 }
 
@@ -4098,9 +4096,11 @@ function tryStreamTask(request: Request, task: Task): void {
     // so that we instead outline the row to get a new debugID if needed.
     debugID = null;
   }
+  const parentSerializedSize = serializedSize;
   try {
     emitChunk(request, task, task.model);
   } finally {
+    serializedSize = parentSerializedSize;
     if (__DEV__) {
       debugID = prevDebugID;
     }
diff --git a/packages/shared/ReactFeatureFlags.js b/packages/shared/ReactFeatureFlags.js
index 10bd08970f8e8..5237e312318e5 100644
--- a/packages/shared/ReactFeatureFlags.js
+++ b/packages/shared/ReactFeatureFlags.js
@@ -100,11 +100,6 @@ export const enableSuspenseyImages = false;
 
 export const enableSrcObject = __EXPERIMENTAL__;
 
-/**
- * Switches the Fabric API from doing layout in commit work instead of complete work.
- */
-export const enableFabricCompleteRootInCommitPhase = false;
-
 /**
  * Switches Fiber creation to a simple object instead of a constructor.
  */
diff --git a/packages/shared/forks/ReactFeatureFlags.native-fb-dynamic.js b/packages/shared/forks/ReactFeatureFlags.native-fb-dynamic.js
index f1ced67c446d9..c2b56602b39f7 100644
--- a/packages/shared/forks/ReactFeatureFlags.native-fb-dynamic.js
+++ b/packages/shared/forks/ReactFeatureFlags.native-fb-dynamic.js
@@ -23,7 +23,6 @@ export const enableHiddenSubtreeInsertionEffectCleanup = __VARIANT__;
 export const enablePersistedModeClonedFlag = __VARIANT__;
 export const enableShallowPropDiffing = __VARIANT__;
 export const passChildrenWhenCloningPersistedNodes = __VARIANT__;
-export const enableFabricCompleteRootInCommitPhase = __VARIANT__;
 export const enableSiblingPrerendering = __VARIANT__;
 export const enableFastAddPropertiesInDiffing = __VARIANT__;
 export const enableLazyPublicInstanceInFabric = __VARIANT__;
diff --git a/packages/shared/forks/ReactFeatureFlags.native-fb.js b/packages/shared/forks/ReactFeatureFlags.native-fb.js
index 6bc3f7b1d1e1f..93c3ebff00886 100644
--- a/packages/shared/forks/ReactFeatureFlags.native-fb.js
+++ b/packages/shared/forks/ReactFeatureFlags.native-fb.js
@@ -20,7 +20,6 @@ const dynamicFlags: DynamicExportsType = (dynamicFlagsUntyped: any);
 // the exports object every time a flag is read.
 export const {
   alwaysThrottleRetries,
-  enableFabricCompleteRootInCommitPhase,
   enableHiddenSubtreeInsertionEffectCleanup,
   enableObjectFiber,
   enablePersistedModeClonedFlag,
diff --git a/packages/shared/forks/ReactFeatureFlags.native-oss.js b/packages/shared/forks/ReactFeatureFlags.native-oss.js
index cb2d97eb70c92..c1e7cebdaecba 100644
--- a/packages/shared/forks/ReactFeatureFlags.native-oss.js
+++ b/packages/shared/forks/ReactFeatureFlags.native-oss.js
@@ -30,7 +30,6 @@ export const enableAsyncIterableChildren = false;
 export const enableCPUSuspense = false;
 export const enableCreateEventHandleAPI = false;
 export const enableDO_NOT_USE_disableStrictPassiveEffect = false;
-export const enableFabricCompleteRootInCommitPhase = false;
 export const enableMoveBefore = true;
 export const enableFizzExternalRuntime = true;
 export const enableHalt = false;
diff --git a/packages/shared/forks/ReactFeatureFlags.test-renderer.js b/packages/shared/forks/ReactFeatureFlags.test-renderer.js
index e4295dec55500..21a95d51cdc9e 100644
--- a/packages/shared/forks/ReactFeatureFlags.test-renderer.js
+++ b/packages/shared/forks/ReactFeatureFlags.test-renderer.js
@@ -36,7 +36,6 @@ export const enableUseEffectEventHook = false;
 export const favorSafetyOverHydrationPerf = true;
 export const enableLegacyFBSupport = false;
 export const enableMoveBefore = false;
-export const enableFabricCompleteRootInCommitPhase = false;
 export const enableHiddenSubtreeInsertionEffectCleanup = false;
 export const enableHydrationLaneScheduling = true;
 
diff --git a/packages/shared/forks/ReactFeatureFlags.test-renderer.native-fb.js b/packages/shared/forks/ReactFeatureFlags.test-renderer.native-fb.js
index dcded1c0a61b4..478e1d7953c39 100644
--- a/packages/shared/forks/ReactFeatureFlags.test-renderer.native-fb.js
+++ b/packages/shared/forks/ReactFeatureFlags.test-renderer.native-fb.js
@@ -60,7 +60,6 @@ export const renameElementSymbol = false;
 export const retryLaneExpirationMs = 5000;
 export const syncLaneExpirationMs = 250;
 export const transitionLaneExpirationMs = 5000;
-export const enableFabricCompleteRootInCommitPhase = false;
 export const enableSiblingPrerendering = true;
 export const enableHydrationLaneScheduling = true;
 export const enableYieldingBeforePassive = false;
diff --git a/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js b/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js
index 71d6f09abb8c4..247950f1fb37b 100644
--- a/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js
+++ b/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js
@@ -39,7 +39,6 @@ export const favorSafetyOverHydrationPerf = true;
 export const enableLegacyFBSupport = false;
 export const enableMoveBefore = false;
 export const enableRenderableContext = false;
-export const enableFabricCompleteRootInCommitPhase = false;
 export const enableHiddenSubtreeInsertionEffectCleanup = true;
 
 export const enableRetryLaneExpiration = false;
diff --git a/packages/shared/forks/ReactFeatureFlags.www.js b/packages/shared/forks/ReactFeatureFlags.www.js
index 079b6e8e92edc..78ff747a065c5 100644
--- a/packages/shared/forks/ReactFeatureFlags.www.js
+++ b/packages/shared/forks/ReactFeatureFlags.www.js
@@ -48,7 +48,6 @@ export const enableProfilerTimer = __PROFILE__;
 export const enableProfilerCommitHooks = __PROFILE__;
 export const enableProfilerNestedUpdatePhase = __PROFILE__;
 export const enableUpdaterTracking = __PROFILE__;
-export const enableFabricCompleteRootInCommitPhase = false;
 
 export const enableSuspenseAvoidThisFallback = true;