[compiler] enablePreserveMemo treats manual deps as non-nullable

The `@enablePreserveExistingMemoizationGuarantees` mode can still fail to preserve manual memoization due to mismtached dependencies. Specifically, where the user's dependencies are more precise than the compiler infers bc the compiler is being conservative about what might be nullable. In this mode though we're intentionally using information from the manual memoization and can also rely on the deps as a signal for what's non-nullable.

The idea of the PR is that we treat manual memo deps just like other inferred-as-non-nullable objects during PropagateScopeDeps. We're careful to not treat the full path as non-nullable, only up to the last property index. So `x.y.z` as a manual dep treats `x` and `x.y` as non-nullable, allowing us to preserve a conditional dependency on `x.y.z`.

Optionals within manual dependencies are a bit trickier and aren't handled yet, but hopefully that's less common and something we can improve in a follow-up. Not handling them just means that developers may hit false positives on validating existing memoization if they use optional chains in manual dependencies.

ReactVersions.js

@@ -7,18 +7,18 @@
 //
 // The @latest channel uses the version as-is, e.g.:
 //
-//   19.2.0
+//   19.3.0
 //
 // The @canary channel appends additional information, with the scheme
 // <version>-<label>-<commit_sha>, e.g.:
 //
-//   19.2.0-canary-a1c2d3e4
+//   19.3.0-canary-a1c2d3e4
 //
 // The @experimental channel doesn't include a version, only a date and a sha, e.g.:
 //
 //   0.0.0-experimental-241c4467e-20200129
 
-const ReactVersion = '19.2.0';
+const ReactVersion = '19.3.0';
 
 // The label used by the @canary channel. Represents the upcoming release's
 // stability. Most of the time, this will be "canary", but we may temporarily
@@ -33,8 +33,8 @@ const canaryChannelLabel = 'canary';
 const rcNumber = 0;
 
 const stablePackages = {
-  'eslint-plugin-react-hooks': '6.1.0',
-  'jest-react': '0.17.0',
+  'eslint-plugin-react-hooks': '6.2.0',
+  'jest-react': '0.18.0',
   react: ReactVersion,
   'react-art': ReactVersion,
   'react-dom': ReactVersion,
@@ -42,12 +42,12 @@ const stablePackages = {
   'react-server-dom-turbopack': ReactVersion,
   'react-server-dom-parcel': ReactVersion,
   'react-is': ReactVersion,
-  'react-reconciler': '0.33.0',
-  'react-refresh': '0.18.0',
+  'react-reconciler': '0.34.0',
+  'react-refresh': '0.19.0',
   'react-test-renderer': ReactVersion,
-  'use-subscription': '1.12.0',
-  'use-sync-external-store': '1.6.0',
-  scheduler: '0.27.0',
+  'use-subscription': '1.13.0',
+  'use-sync-external-store': '1.7.0',
+  scheduler: '0.28.0',
 };
 
 // These packages do not exist in the @canary or @latest channel, only

compiler/apps/playground/components/AccordionWindow.tsx

@@ -23,6 +23,7 @@ export default function AccordionWindow(props: {
   tabsOpen: Set<string>;
   setTabsOpen: (newTab: Set<string>) => void;
   changedPasses: Set<string>;
+  isFailure: boolean;
 }): React.ReactElement {
   return (
     <div className="flex-1 min-w-[550px] sm:min-w-0">
@@ -36,6 +37,7 @@ export default function AccordionWindow(props: {
               tabsOpen={props.tabsOpen}
               setTabsOpen={props.setTabsOpen}
               hasChanged={props.changedPasses.has(name)}
+              isFailure={props.isFailure}
             />
           );
         })}
@@ -50,15 +52,17 @@ function AccordionWindowItem({
   tabsOpen,
   setTabsOpen,
   hasChanged,
+  isFailure,
 }: {
   name: string;
   tabs: TabsRecord;
   tabsOpen: Set<string>;
   setTabsOpen: (newTab: Set<string>) => void;
   hasChanged: boolean;
+  isFailure: boolean;
 }): React.ReactElement {
   const id = useId();
-  const isShow = tabsOpen.has(name);
+  const isShow = isFailure ? name === 'Output' : tabsOpen.has(name);
 
   const transitionName = `accordion-window-item-${id}`;
 

compiler/apps/playground/components/Editor/Output.tsx

@@ -265,14 +265,8 @@ function OutputContent({store, compilerOutput}: Props): JSX.Element {
    * Update the active tab back to the output or errors tab when the compilation state
    * changes between success/failure.
    */
-  const [previousOutputKind, setPreviousOutputKind] = useState(
-    compilerOutput.kind,
-  );
-  if (compilerOutput.kind !== previousOutputKind) {
-    setPreviousOutputKind(compilerOutput.kind);
-    setTabsOpen(new Set(['Output']));
-    setActiveTab('Output');
-  }
+
+  const isFailure = compilerOutput.kind !== 'ok';
   const changedPasses: Set<string> = new Set(['Output', 'HIR']); // Initial and final passes should always be bold
   let lastResult: string = '';
   for (const [passName, results] of compilerOutput.results) {
@@ -301,6 +295,8 @@ function OutputContent({store, compilerOutput}: Props): JSX.Element {
           tabs={tabs}
           activeTab={activeTab}
           onTabChange={setActiveTab}
+          // Display the Output tab on compilation failure
+          activeTabOverride={isFailure ? 'Output' : undefined}
         />
       </ViewTransition>
     );
@@ -319,6 +315,7 @@ function OutputContent({store, compilerOutput}: Props): JSX.Element {
         tabsOpen={tabsOpen}
         tabs={tabs}
         changedPasses={changedPasses}
+        isFailure={isFailure}
       />
     </ViewTransition>
   );

compiler/apps/playground/components/TabbedWindow.tsx

@@ -17,11 +17,15 @@ export default function TabbedWindow({
   tabs,
   activeTab,
   onTabChange,
+  activeTabOverride,
 }: {
   tabs: Map<string, React.ReactNode>;
   activeTab: string;
   onTabChange: (tab: string) => void;
+  activeTabOverride?: string;
 }): React.ReactElement {
+  const currentActiveTab = activeTabOverride ? activeTabOverride : activeTab;
+
   const id = useId();
   const transitionName = `tab-highlight-${id}`;
 
@@ -37,7 +41,7 @@ export default function TabbedWindow({
       <div className="flex flex-col h-full max-w-full">
         <div className="flex p-2 flex-shrink-0">
           {Array.from(tabs.keys()).map(tab => {
-            const isActive = activeTab === tab;
+            const isActive = currentActiveTab === tab;
             return (
               <button
                 key={tab}
@@ -49,6 +53,8 @@ export default function TabbedWindow({
                 {isActive && (
                   <ViewTransition
                     name={transitionName}
+                    enter={{default: 'none'}}
+                    exit={{default: 'none'}}
                     share={{
                       [TOGGLE_TAB_TRANSITION]: 'tab-highlight',
                       default: 'none',
@@ -58,6 +64,8 @@ export default function TabbedWindow({
                   </ViewTransition>
                 )}
                 <ViewTransition
+                  enter={{default: 'none'}}
+                  exit={{default: 'none'}}
                   update={{
                     [TOGGLE_TAB_TRANSITION]: 'tab-text',
                     default: 'none',
@@ -69,7 +77,7 @@ export default function TabbedWindow({
           })}
         </div>
         <div className="flex-1 overflow-hidden w-full h-full">
-          {tabs.get(activeTab)}
+          {tabs.get(currentActiveTab)}
         </div>
       </div>
     </div>

compiler/packages/babel-plugin-react-compiler/src/HIR/CollectHoistablePropertyLoads.ts

@@ -454,6 +454,32 @@ function collectNonNullsInBlocks(
             assumedNonNullObjects.add(entry);
           }
         }
+      } else if (
+        fn.env.config.enablePreserveExistingMemoizationGuarantees &&
+        instr.value.kind === 'StartMemoize' &&
+        instr.value.deps != null
+      ) {
+        for (const dep of instr.value.deps) {
+          if (dep.root.kind === 'NamedLocal') {
+            if (
+              !isImmutableAtInstr(dep.root.value.identifier, instr.id, context)
+            ) {
+              continue;
+            }
+            for (let i = 0; i < dep.path.length; i++) {
+              const pathEntry = dep.path[i]!;
+              if (pathEntry.optional) {
+                break;
+              }
+              const depNode = context.registry.getOrCreateProperty({
+                identifier: dep.root.value.identifier,
+                path: dep.path.slice(0, i),
+                reactive: dep.root.value.reactive,
+              });
+              assumedNonNullObjects.add(depNode);
+            }
+          }
+        }
       }
     }
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-preserve-memo-deps-mixed-optional-nonoptional-property-chain.expect.md

@@ -0,0 +1,91 @@
+
+## Input
+
+```javascript
+// @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees @enableOptionalDependencies @enableTreatFunctionDepsAsConditional:false
+
+import {useMemo} from 'react';
+import {identity, ValidateMemoization} from 'shared-runtime';
+
+function Component({x}) {
+  const object = useMemo(() => {
+    return identity({
+      callback: () => {
+        // This is a bug in our dependency inference: we stop capturing dependencies
+        // after x.a.b?.c. But what this dependency is telling us is that if `x.a.b`
+        // was non-nullish, then we can access `.c.d?.e`. Thus we should take the
+        // full property chain, exactly as-is with optionals/non-optionals, as a
+        // dependency
+        return identity(x.a.b?.c.d?.e);
+      },
+    });
+  }, [x.a.b?.c.d?.e]);
+  const result = useMemo(() => {
+    return [object.callback()];
+  }, [object]);
+  return <Inner x={x} result={result} />;
+}
+
+function Inner({x, result}) {
+  'use no memo';
+  return <ValidateMemoization inputs={[x.y.z]} output={result} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{x: {y: {z: 42}}}],
+  sequentialRenders: [
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 3.14}}},
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 3.14}}},
+    {x: {y: {z: 42}}},
+  ],
+};
+
+```
+
+
+## Error
+
+```
+Found 1 error:
+
+Compilation Skipped: Existing memoization could not be preserved
+
+React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `x.a.b?.c`, but the source dependencies were [x.a.b?.c.d?.e]. Inferred less specific property than source.
+
+error.todo-preserve-memo-deps-mixed-optional-nonoptional-property-chain.ts:7:25
+   5 |
+   6 | function Component({x}) {
+>  7 |   const object = useMemo(() => {
+     |                          ^^^^^^^
+>  8 |     return identity({
+     | ^^^^^^^^^^^^^^^^^^^^^
+>  9 |       callback: () => {
+     | ^^^^^^^^^^^^^^^^^^^^^
+> 10 |         // This is a bug in our dependency inference: we stop capturing dependencies
+     | ^^^^^^^^^^^^^^^^^^^^^
+> 11 |         // after x.a.b?.c. But what this dependency is telling us is that if `x.a.b`
+     | ^^^^^^^^^^^^^^^^^^^^^
+> 12 |         // was non-nullish, then we can access `.c.d?.e`. Thus we should take the
+     | ^^^^^^^^^^^^^^^^^^^^^
+> 13 |         // full property chain, exactly as-is with optionals/non-optionals, as a
+     | ^^^^^^^^^^^^^^^^^^^^^
+> 14 |         // dependency
+     | ^^^^^^^^^^^^^^^^^^^^^
+> 15 |         return identity(x.a.b?.c.d?.e);
+     | ^^^^^^^^^^^^^^^^^^^^^
+> 16 |       },
+     | ^^^^^^^^^^^^^^^^^^^^^
+> 17 |     });
+     | ^^^^^^^^^^^^^^^^^^^^^
+> 18 |   }, [x.a.b?.c.d?.e]);
+     | ^^^^ Could not preserve existing manual memoization
+  19 |   const result = useMemo(() => {
+  20 |     return [object.callback()];
+  21 |   }, [object]);
+```
+          
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-preserve-memo-deps-mixed-optional-nonoptional-property-chain.js

@@ -0,0 +1,41 @@
+// @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees @enableOptionalDependencies @enableTreatFunctionDepsAsConditional:false
+
+import {useMemo} from 'react';
+import {identity, ValidateMemoization} from 'shared-runtime';
+
+function Component({x}) {
+  const object = useMemo(() => {
+    return identity({
+      callback: () => {
+        // This is a bug in our dependency inference: we stop capturing dependencies
+        // after x.a.b?.c. But what this dependency is telling us is that if `x.a.b`
+        // was non-nullish, then we can access `.c.d?.e`. Thus we should take the
+        // full property chain, exactly as-is with optionals/non-optionals, as a
+        // dependency
+        return identity(x.a.b?.c.d?.e);
+      },
+    });
+  }, [x.a.b?.c.d?.e]);
+  const result = useMemo(() => {
+    return [object.callback()];
+  }, [object]);
+  return <Inner x={x} result={result} />;
+}
+
+function Inner({x, result}) {
+  'use no memo';
+  return <ValidateMemoization inputs={[x.y.z]} output={result} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{x: {y: {z: 42}}}],
+  sequentialRenders: [
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 3.14}}},
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 3.14}}},
+    {x: {y: {z: 42}}},
+  ],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-deps-conditional-property-chain-less-precise-deps.expect.md

@@ -0,0 +1,122 @@
+
+## Input
+
+```javascript
+// @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees @enableOptionalDependencies @enableTreatFunctionDepsAsConditional:false
+
+import {useMemo} from 'react';
+import {identity, ValidateMemoization} from 'shared-runtime';
+
+function Component({x}) {
+  const object = useMemo(() => {
+    return identity({
+      callback: () => {
+        return identity(x.y.z); // accesses more levels of properties than the manual memo
+      },
+    });
+    // x.y as a manual dep only tells us that x is non-nullable, not that x.y is non-nullable
+    // we can only take a dep on x.y, not x.y.z
+  }, [x.y]);
+  const result = useMemo(() => {
+    return [object.callback()];
+  }, [object]);
+  return <ValidateMemoization inputs={[x.y]} output={result} />;
+}
+
+const input1 = {x: {y: {z: 42}}};
+const input1b = {x: {y: {z: 42}}};
+const input2 = {x: {y: {z: 3.14}}};
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [input1],
+  sequentialRenders: [
+    input1,
+    input1,
+    input1b, // should reset even though .z didn't change
+    input1,
+    input2,
+  ],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees @enableOptionalDependencies @enableTreatFunctionDepsAsConditional:false
+
+import { useMemo } from "react";
+import { identity, ValidateMemoization } from "shared-runtime";
+
+function Component(t0) {
+  const $ = _c(11);
+  const { x } = t0;
+  let t1;
+  if ($[0] !== x.y) {
+    t1 = identity({ callback: () => identity(x.y.z) });
+    $[0] = x.y;
+    $[1] = t1;
+  } else {
+    t1 = $[1];
+  }
+  const object = t1;
+  let t2;
+  if ($[2] !== object) {
+    t2 = object.callback();
+    $[2] = object;
+    $[3] = t2;
+  } else {
+    t2 = $[3];
+  }
+  let t3;
+  if ($[4] !== t2) {
+    t3 = [t2];
+    $[4] = t2;
+    $[5] = t3;
+  } else {
+    t3 = $[5];
+  }
+  const result = t3;
+  let t4;
+  if ($[6] !== x.y) {
+    t4 = [x.y];
+    $[6] = x.y;
+    $[7] = t4;
+  } else {
+    t4 = $[7];
+  }
+  let t5;
+  if ($[8] !== result || $[9] !== t4) {
+    t5 = <ValidateMemoization inputs={t4} output={result} />;
+    $[8] = result;
+    $[9] = t4;
+    $[10] = t5;
+  } else {
+    t5 = $[10];
+  }
+  return t5;
+}
+
+const input1 = { x: { y: { z: 42 } } };
+const input1b = { x: { y: { z: 42 } } };
+const input2 = { x: { y: { z: 3.14 } } };
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [input1],
+  sequentialRenders: [
+    input1,
+    input1,
+    input1b, // should reset even though .z didn't change
+    input1,
+    input2,
+  ],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"inputs":[{"z":42}],"output":[42]}</div>
+<div>{"inputs":[{"z":42}],"output":[42]}</div>
+<div>{"inputs":[{"z":42}],"output":[42]}</div>
+<div>{"inputs":[{"z":42}],"output":[42]}</div>
+<div>{"inputs":[{"z":3.14}],"output":[3.14]}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-deps-conditional-property-chain-less-precise-deps.js

@@ -0,0 +1,35 @@
+// @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees @enableOptionalDependencies @enableTreatFunctionDepsAsConditional:false
+
+import {useMemo} from 'react';
+import {identity, ValidateMemoization} from 'shared-runtime';
+
+function Component({x}) {
+  const object = useMemo(() => {
+    return identity({
+      callback: () => {
+        return identity(x.y.z); // accesses more levels of properties than the manual memo
+      },
+    });
+    // x.y as a manual dep only tells us that x is non-nullable, not that x.y is non-nullable
+    // we can only take a dep on x.y, not x.y.z
+  }, [x.y]);
+  const result = useMemo(() => {
+    return [object.callback()];
+  }, [object]);
+  return <ValidateMemoization inputs={[x.y]} output={result} />;
+}
+
+const input1 = {x: {y: {z: 42}}};
+const input1b = {x: {y: {z: 42}}};
+const input2 = {x: {y: {z: 3.14}}};
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [input1],
+  sequentialRenders: [
+    input1,
+    input1,
+    input1b, // should reset even though .z didn't change
+    input1,
+    input2,
+  ],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-deps-conditional-property-chain.expect.md

@@ -0,0 +1,117 @@
+
+## Input
+
+```javascript
+// @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees @enableOptionalDependencies @enableTreatFunctionDepsAsConditional:false
+
+import {useMemo} from 'react';
+import {identity, ValidateMemoization} from 'shared-runtime';
+
+function Component({x}) {
+  const object = useMemo(() => {
+    return identity({
+      callback: () => {
+        return identity(x.y.z);
+      },
+    });
+  }, [x.y.z]);
+  const result = useMemo(() => {
+    return [object.callback()];
+  }, [object]);
+  return <ValidateMemoization inputs={[x.y.z]} output={result} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{x: {y: {z: 42}}}],
+  sequentialRenders: [
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 3.14}}},
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 3.14}}},
+    {x: {y: {z: 42}}},
+  ],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees @enableOptionalDependencies @enableTreatFunctionDepsAsConditional:false
+
+import { useMemo } from "react";
+import { identity, ValidateMemoization } from "shared-runtime";
+
+function Component(t0) {
+  const $ = _c(11);
+  const { x } = t0;
+  let t1;
+  if ($[0] !== x.y.z) {
+    t1 = identity({ callback: () => identity(x.y.z) });
+    $[0] = x.y.z;
+    $[1] = t1;
+  } else {
+    t1 = $[1];
+  }
+  const object = t1;
+  let t2;
+  if ($[2] !== object) {
+    t2 = object.callback();
+    $[2] = object;
+    $[3] = t2;
+  } else {
+    t2 = $[3];
+  }
+  let t3;
+  if ($[4] !== t2) {
+    t3 = [t2];
+    $[4] = t2;
+    $[5] = t3;
+  } else {
+    t3 = $[5];
+  }
+  const result = t3;
+  let t4;
+  if ($[6] !== x.y.z) {
+    t4 = [x.y.z];
+    $[6] = x.y.z;
+    $[7] = t4;
+  } else {
+    t4 = $[7];
+  }
+  let t5;
+  if ($[8] !== result || $[9] !== t4) {
+    t5 = <ValidateMemoization inputs={t4} output={result} />;
+    $[8] = result;
+    $[9] = t4;
+    $[10] = t5;
+  } else {
+    t5 = $[10];
+  }
+  return t5;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ x: { y: { z: 42 } } }],
+  sequentialRenders: [
+    { x: { y: { z: 42 } } },
+    { x: { y: { z: 42 } } },
+    { x: { y: { z: 3.14 } } },
+    { x: { y: { z: 42 } } },
+    { x: { y: { z: 3.14 } } },
+    { x: { y: { z: 42 } } },
+  ],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"inputs":[42],"output":[42]}</div>
+<div>{"inputs":[42],"output":[42]}</div>
+<div>{"inputs":[3.14],"output":[3.14]}</div>
+<div>{"inputs":[42],"output":[42]}</div>
+<div>{"inputs":[3.14],"output":[3.14]}</div>
+<div>{"inputs":[42],"output":[42]}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-deps-conditional-property-chain.js

@@ -0,0 +1,31 @@
+// @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees @enableOptionalDependencies @enableTreatFunctionDepsAsConditional:false
+
+import {useMemo} from 'react';
+import {identity, ValidateMemoization} from 'shared-runtime';
+
+function Component({x}) {
+  const object = useMemo(() => {
+    return identity({
+      callback: () => {
+        return identity(x.y.z);
+      },
+    });
+  }, [x.y.z]);
+  const result = useMemo(() => {
+    return [object.callback()];
+  }, [object]);
+  return <ValidateMemoization inputs={[x.y.z]} output={result} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{x: {y: {z: 42}}}],
+  sequentialRenders: [
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 3.14}}},
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 3.14}}},
+    {x: {y: {z: 42}}},
+  ],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-deps-optional-property-chain.expect.md

@@ -0,0 +1,125 @@
+
+## Input
+
+```javascript
+// @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees @enableOptionalDependencies @enableTreatFunctionDepsAsConditional:false
+
+import {useMemo} from 'react';
+import {identity, ValidateMemoization} from 'shared-runtime';
+
+function Component({x, y, z}) {
+  const object = useMemo(() => {
+    return identity({
+      callback: () => {
+        return identity(x?.y?.z, y.a?.b, z.a.b?.c);
+      },
+    });
+  }, [x?.y?.z, y.a?.b, z.a.b?.c]);
+  const result = useMemo(() => {
+    return [object.callback()];
+  }, [object]);
+  return <Inner x={x} result={result} />;
+}
+
+function Inner({x, result}) {
+  'use no memo';
+  return <ValidateMemoization inputs={[x.y.z]} output={result} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{x: {y: {z: 42}}}],
+  sequentialRenders: [
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 3.14}}},
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 3.14}}},
+    {x: {y: {z: 42}}},
+  ],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees @enableOptionalDependencies @enableTreatFunctionDepsAsConditional:false
+
+import { useMemo } from "react";
+import { identity, ValidateMemoization } from "shared-runtime";
+
+function Component(t0) {
+  const $ = _c(11);
+  const { x, y, z } = t0;
+
+  x?.y?.z;
+  y.a?.b;
+  z.a.b?.c;
+  let t1;
+  if ($[0] !== x?.y?.z || $[1] !== y.a?.b || $[2] !== z.a.b?.c) {
+    t1 = identity({ callback: () => identity(x?.y?.z, y.a?.b, z.a.b?.c) });
+    $[0] = x?.y?.z;
+    $[1] = y.a?.b;
+    $[2] = z.a.b?.c;
+    $[3] = t1;
+  } else {
+    t1 = $[3];
+  }
+  const object = t1;
+  let t2;
+  if ($[4] !== object) {
+    t2 = object.callback();
+    $[4] = object;
+    $[5] = t2;
+  } else {
+    t2 = $[5];
+  }
+  let t3;
+  if ($[6] !== t2) {
+    t3 = [t2];
+    $[6] = t2;
+    $[7] = t3;
+  } else {
+    t3 = $[7];
+  }
+  const result = t3;
+  let t4;
+  if ($[8] !== result || $[9] !== x) {
+    t4 = <Inner x={x} result={result} />;
+    $[8] = result;
+    $[9] = x;
+    $[10] = t4;
+  } else {
+    t4 = $[10];
+  }
+  return t4;
+}
+
+function Inner({ x, result }) {
+  "use no memo";
+  return <ValidateMemoization inputs={[x.y.z]} output={result} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ x: { y: { z: 42 } } }],
+  sequentialRenders: [
+    { x: { y: { z: 42 } } },
+    { x: { y: { z: 42 } } },
+    { x: { y: { z: 3.14 } } },
+    { x: { y: { z: 42 } } },
+    { x: { y: { z: 3.14 } } },
+    { x: { y: { z: 42 } } },
+  ],
+};
+
+```
+      
+### Eval output
+(kind: ok) [[ (exception in render) TypeError: Cannot read properties of undefined (reading 'a') ]]
+[[ (exception in render) TypeError: Cannot read properties of undefined (reading 'a') ]]
+[[ (exception in render) TypeError: Cannot read properties of undefined (reading 'a') ]]
+[[ (exception in render) TypeError: Cannot read properties of undefined (reading 'a') ]]
+[[ (exception in render) TypeError: Cannot read properties of undefined (reading 'a') ]]
+[[ (exception in render) TypeError: Cannot read properties of undefined (reading 'a') ]]

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-deps-optional-property-chain.js

@@ -0,0 +1,36 @@
+// @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees @enableOptionalDependencies @enableTreatFunctionDepsAsConditional:false
+
+import {useMemo} from 'react';
+import {identity, ValidateMemoization} from 'shared-runtime';
+
+function Component({x, y, z}) {
+  const object = useMemo(() => {
+    return identity({
+      callback: () => {
+        return identity(x?.y?.z, y.a?.b, z.a.b?.c);
+      },
+    });
+  }, [x?.y?.z, y.a?.b, z.a.b?.c]);
+  const result = useMemo(() => {
+    return [object.callback()];
+  }, [object]);
+  return <Inner x={x} result={result} />;
+}
+
+function Inner({x, result}) {
+  'use no memo';
+  return <ValidateMemoization inputs={[x.y.z]} output={result} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{x: {y: {z: 42}}}],
+  sequentialRenders: [
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 3.14}}},
+    {x: {y: {z: 42}}},
+    {x: {y: {z: 3.14}}},
+    {x: {y: {z: 42}}},
+  ],
+};

packages/react-art/package.json

@@ -1,7 +1,7 @@
 {
   "name": "react-art",
   "description": "React ART is a JavaScript library for drawing vector graphics using React. It provides declarative and reactive bindings to the ART library. Using the same declarative API you can render the output to either Canvas, SVG or VML (IE8).",
-  "version": "19.2.0",
+  "version": "19.3.0",
   "main": "index.js",
   "repository": {
     "type": "git",
@@ -24,10 +24,10 @@
   "dependencies": {
     "art": "^0.10.1",
     "create-react-class": "^15.6.2",
-    "scheduler": "^0.27.0"
+    "scheduler": "^0.28.0"
   },
   "peerDependencies": {
-    "react": "^19.2.0"
+    "react": "^19.3.0"
   },
   "files": [
     "LICENSE",

packages/react-devtools-shell/src/app/InspectableElements/UseEffectEvent.js

@@ -1,6 +1,8 @@
 import * as React from 'react';
 
-const {experimental_useEffectEvent, useState, useEffect} = React;
+const {useState, useEffect} = React;
+const useEffectEvent =
+  React.useEffectEvent || React.experimental_useEffectEvent;
 
 export default function UseEffectEvent(): React.Node {
   return (
@@ -12,14 +14,14 @@ export default function UseEffectEvent(): React.Node {
 }
 
 function SingleHookCase() {
-  const onClick = experimental_useEffectEvent(() => {});
+  const onClick = useEffectEvent(() => {});
 
   return <div onClick={onClick} />;
 }
 
 function useCustomHook() {
   const [state, setState] = useState();
-  const onClick = experimental_useEffectEvent(() => {});
+  const onClick = useEffectEvent(() => {});
   useEffect(() => {});
 
   return [state, setState, onClick];

packages/react-dom-bindings/package.json

@@ -1,7 +1,7 @@
 {
   "name": "react-dom-bindings",
   "description": "React implementation details for react-dom.",
-  "version": "19.2.0",
+  "version": "19.3.0",
   "private": true,
   "main": "index.js",
   "repository": {

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

@@ -2279,6 +2279,11 @@ export function startViewTransition(
       spawnedWorkCallback();
     };
     const handleError = (error: mixed) => {
+      // $FlowFixMe[prop-missing]
+      if (ownerDocument.__reactViewTransition === transition) {
+        // $FlowFixMe[prop-missing]
+        ownerDocument.__reactViewTransition = null;
+      }
       try {
         error = customizeViewTransitionError(error, false);
         if (error !== null) {
@@ -2293,6 +2298,9 @@ export function startViewTransition(
         layoutCallback();
         // Skip afterMutationCallback() since we're not animating.
         spawnedWorkCallback();
+        if (enableProfilerTimer) {
+          finishedAnimation();
+        }
       }
     };
     transition.ready.then(readyCallback, handleError);
@@ -2699,6 +2707,11 @@ export function startGestureTransition(
         ? () => requestAnimationFrame(readyCallback)
         : readyCallback;
     const handleError = (error: mixed) => {
+      // $FlowFixMe[prop-missing]
+      if (ownerDocument.__reactViewTransition === transition) {
+        // $FlowFixMe[prop-missing]
+        ownerDocument.__reactViewTransition = null;
+      }
       try {
         error = customizeViewTransitionError(error, true);
         if (error !== null) {
@@ -2713,6 +2726,9 @@ export function startGestureTransition(
         // Skip readyCallback() and go straight to animateCallbck() since we're not animating.
         // animateCallback() is still required to restore states.
         animateCallback();
+        if (enableProfilerTimer) {
+          finishedAnimation();
+        }
       }
     };
     transition.ready.then(readyForAnimations, handleError);

packages/react-dom/package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-dom",
-  "version": "19.2.0",
+  "version": "19.3.0",
   "description": "React package for working with the DOM.",
   "main": "index.js",
   "repository": {
@@ -17,10 +17,10 @@
   },
   "homepage": "https://react.dev/",
   "dependencies": {
-    "scheduler": "^0.27.0"
+    "scheduler": "^0.28.0"
   },
   "peerDependencies": {
-    "react": "^19.2.0"
+    "react": "^19.3.0"
   },
   "files": [
     "LICENSE",

packages/react-is/package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-is",
-  "version": "19.2.0",
+  "version": "19.3.0",
   "description": "Brand checking of React Elements.",
   "main": "index.js",
   "sideEffects": false,

packages/react-markup/package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-markup",
-  "version": "19.2.0",
+  "version": "19.3.0",
   "description": "React package generating embedded markup such as e-mails with support for Server Components.",
   "main": "index.js",
   "repository": {

packages/react-native-renderer/package.json

@@ -8,7 +8,7 @@
     "directory": "packages/react-native-renderer"
   },
   "dependencies": {
-    "scheduler": "^0.27.0"
+    "scheduler": "^0.28.0"
   },
   "peerDependencies": {
     "react": "^18.0.0"

packages/react-reconciler/package.json

@@ -1,7 +1,7 @@
 {
   "name": "react-reconciler",
   "description": "React package for creating custom renderers.",
-  "version": "0.33.0",
+  "version": "0.34.0",
   "keywords": [
     "react"
   ],
@@ -26,9 +26,9 @@
     "node": ">=0.10.0"
   },
   "peerDependencies": {
-    "react": "^19.2.0"
+    "react": "^19.3.0"
   },
   "dependencies": {
-    "scheduler": "^0.27.0"
+    "scheduler": "^0.28.0"
   }
 }

packages/react-refresh/package.json

@@ -4,7 +4,7 @@
   "keywords": [
     "react"
   ],
-  "version": "0.18.0",
+  "version": "0.19.0",
   "homepage": "https://react.dev/",
   "bugs": "https://github.com/facebook/react/issues",
   "license": "MIT",

packages/react-server-dom-esm/package.json

@@ -1,7 +1,7 @@
 {
   "name": "react-server-dom-esm",
   "description": "React Server Components bindings for DOM using ESM. This is intended to be integrated into meta-frameworks. It is not intended to be imported directly.",
-  "version": "19.2.0",
+  "version": "19.3.0",
   "keywords": [
     "react"
   ],

packages/react-server-dom-fb/package.json

@@ -8,7 +8,7 @@
     "directory": "packages/react-server-dom-fb"
   },
   "dependencies": {
-    "scheduler": "^0.27.0"
+    "scheduler": "^0.28.0"
   },
   "peerDependencies": {
     "react": "^18.0.0",

packages/react-server-dom-parcel/package.json

@@ -1,7 +1,7 @@
 {
   "name": "react-server-dom-parcel",
   "description": "React Server Components bindings for DOM using Parcel. This is intended to be integrated into meta-frameworks. It is not intended to be imported directly.",
-  "version": "19.2.0",
+  "version": "19.3.0",
   "keywords": [
     "react"
   ],
@@ -79,7 +79,7 @@
     "node": ">=0.10.0"
   },
   "peerDependencies": {
-    "react": "^19.2.0",
-    "react-dom": "^19.2.0"
+    "react": "^19.3.0",
+    "react-dom": "^19.3.0"
   }
 }

packages/react-server-dom-turbopack/package.json

@@ -1,7 +1,7 @@
 {
   "name": "react-server-dom-turbopack",
   "description": "React Server Components bindings for DOM using Turbopack. This is intended to be integrated into meta-frameworks. It is not intended to be imported directly.",
-  "version": "19.2.0",
+  "version": "19.3.0",
   "keywords": [
     "react"
   ],
@@ -79,8 +79,8 @@
     "node": ">=0.10.0"
   },
   "peerDependencies": {
-    "react": "^19.2.0",
-    "react-dom": "^19.2.0"
+    "react": "^19.3.0",
+    "react-dom": "^19.3.0"
   },
   "dependencies": {
     "acorn-loose": "^8.3.0",

packages/react-server-dom-webpack/package.json

@@ -1,7 +1,7 @@
 {
   "name": "react-server-dom-webpack",
   "description": "React Server Components bindings for DOM using Webpack. This is intended to be integrated into meta-frameworks. It is not intended to be imported directly.",
-  "version": "19.2.0",
+  "version": "19.3.0",
   "keywords": [
     "react"
   ],
@@ -100,8 +100,8 @@
     "node": ">=0.10.0"
   },
   "peerDependencies": {
-    "react": "^19.2.0",
-    "react-dom": "^19.2.0",
+    "react": "^19.3.0",
+    "react-dom": "^19.3.0",
     "webpack": "^5.59.0"
   },
   "dependencies": {

packages/react-test-renderer/package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-test-renderer",
-  "version": "19.2.0",
+  "version": "19.3.0",
   "description": "React package for snapshot testing.",
   "main": "index.js",
   "repository": {
@@ -19,11 +19,11 @@
   },
   "homepage": "https://react.dev/",
   "dependencies": {
-    "react-is": "^19.2.0",
-    "scheduler": "^0.27.0"
+    "react-is": "^19.3.0",
+    "scheduler": "^0.28.0"
   },
   "peerDependencies": {
-    "react": "^19.2.0"
+    "react": "^19.3.0"
   },
   "files": [
     "LICENSE",

packages/react/package.json

@@ -4,7 +4,7 @@
   "keywords": [
     "react"
   ],
-  "version": "19.2.0",
+  "version": "19.3.0",
   "homepage": "https://react.dev/",
   "bugs": "https://github.com/facebook/react/issues",
   "license": "MIT",

packages/scheduler/package.json

@@ -1,6 +1,6 @@
 {
   "name": "scheduler",
-  "version": "0.27.0",
+  "version": "0.28.0",
   "description": "Cooperative scheduler for the browser environment.",
   "repository": {
     "type": "git",

packages/shared/ReactVersion.js

@@ -12,4 +12,4 @@
 // TODO: This module is used both by the release scripts and to expose a version
 // at runtime. We should instead inject the version number as part of the build
 // process, and use the ReactVersions.js module as the single source of truth.
-export default '19.2.0';
+export default '19.3.0';

packages/use-subscription/package.json

@@ -1,7 +1,7 @@
 {
   "name": "use-subscription",
   "description": "Reusable hooks",
-  "version": "1.12.0",
+  "version": "1.13.0",
   "repository": {
     "type": "git",
     "url": "https://github.com/facebook/react.git",

packages/use-sync-external-store/package.json

@@ -1,7 +1,7 @@
 {
   "name": "use-sync-external-store",
   "description": "Backwards compatible shim for React's useSyncExternalStore. Works with any React that supports hooks.",
-  "version": "1.6.0",
+  "version": "1.7.0",
   "exports": {
     ".": "./index.js",
     "./with-selector": "./with-selector.js",