Ricky

This commit **corrects terminology** within **React's error messages** related to the `useActionState` hook. It updates all references from "form state" to "action state" for improved accuracy and consistency, reflecting the hook's broader applicability. This **bug fix** impacts the **`react-reconciler`** runtime by modifying the error message in `dispatchActionState`, updates a corresponding test in **`react-dom`**, and revises the error code definition in `scripts/error-codes/codes.json`. The change ensures developers receive clear and consistent error messages when interacting with `useActionState`.

This commit introduces the `enableTrustedTypesIntegration` feature flag, enabling **React's integration** with the browser's **Trusted Types API**. Previously, React's **DOM rendering mechanism** would stringify values for `dangerouslySetInnerHTML` and various attributes, inadvertently breaking Trusted Types enforcement and causing `TypeError`s. This **new capability** now ensures that `TrustedHTML` and `TrustedScriptURL` objects are passed directly to DOM APIs, preserving their type and allowing proper **XSS prevention**. This **compatibility fix** primarily benefits applications leveraging Trusted Types, with no behavioral change for those not using the API.

This commit delivers a **bug fix** to the **React Fiber reconciler's error logging** mechanism, preventing internal `<Offscreen>` components from appearing in error messages. Previously, errors occurring within lazy components directly nested under `<Suspense>` or `<Activity>` would incorrectly report `<Offscreen>`. The `getComponentNameFromFiber` function in `packages/react-reconciler/src/getComponentNameFromFiber.js` is now modified to skip this internal component and instead return the name of its user-facing parent. This change significantly improves the **developer experience** by providing more semantically relevant and actionable error messages. New test cases have been added to `ReactIncrementalErrorLogging-test.js` to ensure this corrected behavior.

This commit **disables** the `enableParallelTransitions` feature flag within the **ReactFeatureFlags** system by setting its value to `false` in `packages/shared/ReactFeatureFlags.js`. This is a **fix** to revert an accidental enablement of the **parallel transitions** functionality in **canary builds**. The change ensures that this experimental feature remains inactive, preventing unintended behavior or premature exposure in development versions.

This commit introduces the **`enableEffectEventMutationPhase` feature flag** to control a significant internal change within the **React Reconciler's commit process**. It **refactors** how `useEffectEvent` callbacks are updated, moving this operation to the mutation phase, specifically impacting `commitBeforeMutationEffectsOnFiber` and `commitMutationEffectsOnFiber`. This adjustment serves as a small **optimization** and, more importantly, **fixes a bug** where `useEffectEvent` callbacks failed to update correctly when a component tree became visible after being hidden, particularly when `enableViewTransition` was enabled. New test cases have been added to ensure the correct ordering and behavior of `useEffectEvent` with interleaved effects and `Activity` components.

This commit **adds a new test case** to `packages/react-reconciler/src/__tests__/Activity-test.js` to verify a critical lifecycle behavior. The test specifically ensures that the `getSnapshotBeforeUpdate` method **does not execute in hidden component trees** when the `enableViewTransition` feature is active. This **test addition** validates a **bugfix** that prevents `getSnapshotBeforeUpdate` from running incorrectly for components that are not yet visible, aligning its behavior with `componentWillUpdate`. This ensures correct component state management and lifecycle execution, particularly during view transitions where component visibility changes.

This commit introduces the **`enableParallelTransitions` feature flag** within the **React scheduler and reconciler**, allowing for more independent completion of concurrent transitions. This **new capability** modifies the **lane prioritization logic** in `ReactFiberLane.js` to reduce unnecessary entanglement of transition lanes, potentially improving perceived performance by letting independent updates commit in parallel. While the flag is set to `true` by default in the main `ReactFeatureFlags.js`, it is explicitly disabled for most external builds and is currently intended for **internal research and experimentation** at Meta to assess its benefits and potential breaking changes. New test cases have been added to verify the updated transition and `useDeferredValue` behavior.

This commit introduces a **new capability** for **React Server Components (RSC)**, allowing them to seamlessly import and render `Context.Provider` from client modules. Previously, lazy-resolved `REACT_CONTEXT_TYPE` components were not correctly handled, leading to errors when a Server Component attempted to use a client-defined context. The core change involves modifying `mountLazyComponent` in `packages/react-reconciler` to properly process these lazy-loaded context types. This enhancement significantly improves **context management** patterns within RSC, enabling more flexible state sharing and component composition between server and client boundaries.

This commit **fixes a test failure** in `ReactDOMAttribute-test.js` within the **`react-dom` testing suite**, addressing a **JSDOM bug** related to implicit string coercion. It introduces a **JSDOM hack** to `Element.prototype.setAttribute` for the test environment, ensuring correct behavior when attributes are set. This workaround, similar to one in `ReactDOMSelect-test.js`, clarifies **trusted types** error expectations and guarantees consistent string coercion behavior between development and production builds. The change specifically targets the test environment to accurately validate attribute handling.

This commit **refactors the internal test infrastructure** by **removing the `withoutStack` option** from the `consoleMock` assertion helpers, specifically the `createLogAssertion` utility. This option became obsolete as these helpers now consistently **mandate the presence of a component stack** in console messages during tests. Consequently, numerous test files across various React packages, including `react-dom`, `react-reconciler`, and `react`, have been updated to remove the now-unnecessary `withoutStack` argument from calls to `assertConsoleErrorDev` and `assertConsoleWarnDev`. This change simplifies the test API and ensures uniform console assertion behavior within the project's test suite.

This commit introduces the **initial setup and configuration for the Claude AI assistant** within the monorepo, significantly enhancing **developer tooling and workflow**. It establishes a sophisticated context management system to ensure the assistant's knowledge and skills are correctly scoped, preventing parent configurations from interfering when working within the nested `compiler/` directory. This is achieved by conditionally loading general repository instructions via a `SessionStart` hook and explicitly denying parent skills in `compiler/.claude/settings.json`. Additionally, a suite of **new React-specific skills** like `/flow`, `/test`, and `/fix` are added, providing targeted assistance for common development tasks and improving developer productivity.

This commit **removes the `enableHydrationLaneScheduling` feature flag** from the **React reconciler**, marking a significant **cleanup** and **refactoring** effort. As this flag was a killswitch that has been enabled for over a year, its removal simplifies the codebase by eliminating dead conditional logic. Specifically, it streamlines lane assignment within `mountDehydratedSuspenseComponent` in `packages/react-reconciler/src/ReactFiberBeginWork.js` and simplifies lane bumping in `createHydrationContainer` and `attemptHydrationAtCurrentPriority` within `packages/react-reconciler/src/ReactFiberReconciler.js`. This **maintenance** task reduces internal complexity in the core **hydration mechanism** without impacting external behavior or features.

This commit delivers a crucial **bug fix** to resolve **flaky flight tests** that were failing non-deterministically in both local and CI environments. It addresses two distinct sources of test instability: first, by adding an `afterEach` hook to `scripts/jest/setupTests.js` to **disable installed async hooks** and prevent cross-test pollution between tests. Second, it enhances the `normalizeIOInfo` function in `packages/internal-test-utils/debugInfo.js` to **consistently normalize IO information** during snapshotting, specifically handling `undefined` values to mitigate issues caused by non-deterministic `WeakRef` garbage collection. This significantly improves the **reliability and stability of the test suite** by eliminating these non-deterministic failures.

This commit introduces a **new feature** to the **Jest CLI**, enabling a silent test reporter mode. It adds a `--silent` command-line option to `scripts/jest/jest-cli.js`, which configures the test runner to display only failed tests while showing progress with dots. This enhancement significantly **reduces test output verbosity**, making it easier to quickly identify issues and providing a cleaner interface for automated systems or agents that process test results. The change affects the **test reporting mechanism** and improves the developer experience by minimizing unnecessary console output.

This commit **reverts an accidentally merged change** that introduced logic for the `enableEffectEventMutationPhase` feature flag. It removes the conditional code block and associated logic from the `commitBeforeMutationEffectsOnFiber` and `commitMutationEffectsOnFiber` functions within `packages/react-reconciler/src/ReactFiberCommitWork.js`. Additionally, the import for `enableEffectEventMutationPhase` is removed and comments are updated in `packages/react-reconciler/src/ReactFiberFlags.js`. This **maintenance revert** ensures the **React Reconciler** module returns to its prior state, allowing for the feature to be properly reviewed and introduced later.

This commit **refactors** the internal implementation of **`useEffectEvent` callbacks** within the **React Reconciler**. It moves the mutation of these callbacks from the before-mutation phase to the mutation phase, now controlled by a new feature flag, `enableEffectEventMutationPhase`. The previous `enableUseEffectEventHook` flag is entirely removed across all environments, signifying that `useEffectEvent` is no longer gated by a feature flag for its core functionality. This **maintenance** work simplifies the codebase by removing conditional checks in various hook dispatchers and updates internal types, ensuring a more stable and predictable lifecycle for `useEffectEvent`.

This commit **enhances the console assertion utilities** in `packages/internal-test-utils/consoleMock.js` to require exact error messages, including native JavaScript stack traces. To simplify maintenance, a `\n in <stack>` placeholder can now be used in expected messages to denote the presence of a stack trace without needing to hardcode full stack details. This **test infrastructure improvement** affects numerous **React component and feature tests** across various packages, which are updated to leverage these more precise console error expectations. The change improves the **reliability and accuracy of console output assertions**, ensuring that tests catch exact message regressions and environment-specific console output.

This commit **adds support for React's `useOptimistic` hook** to the **React Compiler**, specifically within the `babel-plugin-react-compiler`. It **extends the compiler's High-level Intermediate Representation (HIR)** by introducing new type definitions and stability analysis functions to correctly identify `useOptimistic` and its setter as non-reactive. This **new capability** ensures that components leveraging `useOptimistic` are properly optimized and memoized, preventing unnecessary re-renders. The changes involve updating `Globals.ts` and `ObjectShape.ts` to recognize these new types, and are validated by new test cases for `useCallback` memoization.

This commit **re-enables legacy mode** by reverting the `disableLegacyMode` feature flag from `true` to `false` within the **React feature flags** configuration. Specifically, it modifies `ReactFeatureFlags.native-fb.js` and `ReactFeatureFlags.native-oss.js`, impacting both **Facebook internal native builds** and **open-source native builds**. This is a **temporary maintenance fix** to address **failing tests** in the `react` package, which currently requires legacy mode to function correctly. The change prevents further test failures until the underlying test suite can be updated to support the disabled legacy mode.

This commit **adds new test cases** to `ReactDOMActivity-test.js` to thoroughly validate the interaction between **Portals** and **Activity boundaries**. These tests specifically confirm the expected behavior of how **Portals** function when combined with activity states, including scenarios involving hidden trees, new insertions, `Suspense` components, and layout effects. The work is a **maintenance** task focused on **testing** to ensure the correctness and stability of these complex rendering mechanisms within the **React DOM reconciler**. This enhances confidence in the robust handling of dynamic UI elements and their activity states.