Jiachi Liu

This commit introduces an **enhancement** to the **OpenTelemetry integration** within Next.js, specifically targeting **server-side page route handling**. It **updates the parent OpenTelemetry span's name** in `packages/next/src/server/route-modules/pages/pages-handler.ts` to accurately reflect the current route name. This change provides more descriptive and semantically meaningful tracing data, significantly improving observability and debugging for page requests. As a minor **maintenance chore**, the `.gitignore` file was also updated to exclude `.claude/worktrees` directories.

This commit **fixes a bug** in the **OpenTelemetry integration** by ensuring the `http.route` attribute is correctly propagated to parent spans. It modifies the **Next.js server's core request handling** in `packages/next/src/server/base-server.ts` and the **Pages Router handler** in `packages/next/src/server/route-modules/pages/pages-handler.ts` to include this crucial tracing detail. This **enhances the accuracy of tracing data**, providing more meaningful resource naming in APM tools for both App and Pages Router requests. A comprehensive suite of **new end-to-end tests** has also been added to validate proper parent span propagation across various route types.

This commit **refactors** the **browser log testing infrastructure** to improve the accuracy and reliability of log assertions. It modifies the regular expression used in `browser-logs.test.ts` to **filter out extraneous logging** originating from the test environment itself, such as Webpack HMR messages or internal Next.js hydration complete messages. This **test maintenance** ensures that **browser log snapshots** only capture and assert on application-specific logs, preventing flakiness and focusing tests on the intended output. This specifically impacts **Webpack and App Router hydration error scenarios**, making their log assertions more robust by ignoring environmental noise.

This commit **enhances error logging** within the **Next.js devtools** by including the **owner stack trace** in **forwarded error logs**. It integrates this **new capability** into the **log forwarding mechanism** in `packages/next/src/next-devtools/userspace/app/forward-logs.ts`, specifically affecting functions like `logUnhandledRejection` and `forwardUnhandledError`. A related **bug fix** in `packages/next/src/next-devtools/userspace/app/errors/stitched-error.ts` ensures that a valid owner stack is not inadvertently overwritten with a null value. This **feature** provides developers with more **actionable and complete error traces** directly in the terminal, significantly improving the debugging experience for issues such as hydration errors.

This commit introduces a **significant enhancement to the lockfile mechanism**, allowing the Next.js development server to write detailed information like its PID, port, and URL into the lockfile. The **`napi` lockfile crate** was updated to support writing arbitrary content via `lockfile_try_acquire` and `lockfile_try_acquire_sync`, which is then leveraged by the **development bundler setup** in `packages/next` when `lockDistDir` is enabled. This **feature enables a much-improved developer experience** by providing a **more informative error message** when a user attempts to start a second development server in the same project. The updated error message will now include specifics about the already running server, guiding users on how to resolve the conflict, with new tests validating this behavior and the lockfile content.

This commit **removes the `isolatedDevBuild` flag**, making the behavior of outputting **development builds to a separate `.next/dev` directory the unconditional default**. This significant **refactoring** simplifies the **core build configuration** and **TypeScript integration** by eliminating conditional logic related to the flag. It impacts modules like `next/src/server/config.ts`, `next/src/lib/typescript/`, and `crates/next-api/src/project.rs`, ensuring a consistent project structure. The change **streamlines the development workflow** and is accompanied by **comprehensive documentation updates** across various guides and API references to reflect this new standard behavior.

This commit **refactors** the **development log item format** to output **JSON strings** instead of plain text. Specifically, the `formatLogEntry` method in `packages/next/src/server/dev/browser-logs/file-logger.ts` was updated to serialize log entries. Corresponding **unit and end-to-end tests** were updated to parse and assert against this new structured format, ensuring the integrity of the **browser logging** functionality. This change provides a more **machine-readable and structured output** for development logs, enhancing their utility for automated processing and debugging.

This commit **refactors** the **Next.js MCP (Managed Control Plane) server tools** to standardize their API responses. It changes the output format of functions like `registerGetErrorsTool`, `registerGetLogsTool`, and `registerGetPageMetadataTool` from plain text or markdown to **structured JSON**. This ensures that all data, including error messages, logs, and various metadata, is now **programmatically consumable** by other systems interacting with the MCP. The `format-errors.ts` utility was also updated to produce JSON objects, and corresponding **tests** were adjusted to parse the new JSON outputs, improving the robustness and machine-readability of the MCP's internal communication.

This commit **refactors** the Next.js application to ensure the `global-error` module is consistently available and correctly consumed within the **loader tree**. This involves updating the **app structure** in `next-core` to provide a built-in fallback if a custom `global-error` is not defined, and refining the **app rendering process** in `app-render.tsx` to always include it and add an invariant check for its presence. Redundant logic for defining the global error module variable is removed from `app_page_entry.rs`, and a new invariant error message is added to `errors.json` for unexpected module absence. This change enhances the reliability of **error handling** and required an update to **OpenTelemetry E2E tests** to reflect adjusted component loading counts.

This commit introduces a **new feature** to the **Next.js DevTools hydration diff overlay**, enhancing the debugging experience for developers. It adds a visual indicator badge to the `PseudoHtmlDiff` component header, clearly labeling diff lines as either `+ Client` or `- Server` to denote their rendering origin. This improvement directly addresses user feedback by providing immediate clarity on whether content originates from the client or server, significantly reducing confusion during hydration mismatch debugging. The changes primarily affect the `diff-view.tsx` component and introduce new CSS styles within the dev overlay.

This commit performs **documentation maintenance** within the **agent documentation** by removing a specific "Git Workflow" section from `AGENTS.md`. It eliminates content detailing Graphite usage and updates a build command example from `gt checkout` to `git checkout`. This change simplifies the **documentation** by removing tool-specific guidance, ensuring users are directed towards standard Git commands rather than a particular external workflow tool. The scope is limited to improving the clarity and generality of the **agent setup instructions**.

This commit **stabilizes the configuration for forwarding browser console logs to the terminal** during development by **deprecating `experimental.browserDebugInfoInTerminal`** and introducing a new, stable `logging.browserToTerminal` option. It involves **refactoring** the internal browser log handling within the **Next.js development server** to utilize this new configuration, ensuring consistent behavior across both Webpack and Turbopack hot reloaders. Developers are now encouraged to use `logging.browserToTerminal` for controlling browser log visibility, with automatic migration logic and deprecation warnings in place for the old option. Comprehensive **documentation updates** and **test suite adjustments** are included to reflect these changes.

This commit primarily **refactors** the **Next.js metadata type system** to enhance consistency and compatibility between `Metadata` and `ResolvedMetadata`. It **removes deprecated fields** from the `other` property within `Metadata` and `ResolvedMetadataWithURLs` types, while introducing **warnings** in `resolve-metadata.ts` for the usage of `apple-touch-fullscreen` and `apple-touch-icon-precomposed`. Additionally, it refines types for `Facebook`, `Pinterest`, OpenGraph, and Twitter metadata to allow `null` values and improve type spreading, ensuring a more robust and predictable **developer experience** when defining and resolving metadata.

This commit introduces a **new capability** to the **Next.js development server** by allowing configurable forwarding of browser console logs (errors, warnings, and verbose messages) directly to the terminal. It **enhances the `browserDebugInfoInTerminal` configuration** to support specific log levels, with the default now set to 'warn', and implements **log level filtering** in the `receive-logs.ts` module. Additionally, **refactoring** within the **Next.js DevTools** prevents duplicate logging of server-replayed messages, ensuring a cleaner output. This significantly improves the **developer experience** by centralizing relevant browser debugging information directly in the development terminal.

This commit introduces a **new capability** to provide **server action logging** in development mode, offering detailed insights into server-side operations. It **refactors** the **Next.js API layer** and **custom SWC transforms** to collect and serialize richer metadata for server actions, including their source file paths, line, and column numbers, which are then stored in the module graph and manifest. This enhanced metadata enables the development server to log comprehensive details about each server action's execution, such as arguments and duration, directly within the request logs. The changes significantly improve the debugging experience for developers working with server actions.

This commit **updates the documentation** for **MCP client integration** within the `docs/01-app/02-guides/upgrading/version-16.mdx` guide. It **improves clarity** by adding a direct link to the client configuration details section just before the example code block. This **documentation update** ensures users have accurate and complete information when setting up the MCP client during the upgrade process. The changes also specify the example filename and update the link to the `next-devtools-mcp` documentation, providing a more seamless and guided experience for developers.

This commit **refactors the TypeScript type generation system** to ensure the `next-env.d.ts` file remains consistent between development and build environments. It introduces a new utility, `writeRouteTypesEntryFile`, to create an intermediate entry file (`route-types-entry.d.ts`) that re-exports actual route type definitions, thereby preventing direct, variable imports into `next-env.d.ts`. This **refactoring** primarily impacts the **type generation logic** within `next-typegen.ts` and `writeAppTypeDeclarations.ts`, and updates the **TypeScript setup verification** in `verify-typescript-setup.ts` and `setup-dev-bundler.ts`. The change significantly improves the **reliability and consistency of strict route types** by centralizing their declaration and ensuring `next-env.d.ts` uses a fixed, stable path. This enhancement is validated by extensive new and updated **tests** across development and production builds, particularly for `app-dir` configurations.

This commit introduces a **performance optimization** to the **browser logs file logger** within the Next.js development server. It refactors the `flush` function in `packages/next/src/server/dev/browser-logs/file-logger.ts` to clear the internal log queue array more efficiently. Instead of reassigning the array to a new empty one, the change now sets the array's `length` property to `0`. This **refactoring** reduces unnecessary memory allocations and garbage collection cycles, leading to **more efficient log processing** during development and contributing to a smoother developer experience.

This commit delivers a **bug fix** for the **Next.js DevTools development overlay**, resolving an issue where overlay frames, specifically those displaying error call stacks, sometimes failed to open correctly. It adjusts the `onToggleIgnoreList` function within the `error-overlay-call-stack.tsx` component to properly handle null dialog references when closing the ignore list and to ensure the initial dialog height is stored accurately. This enhancement improves the reliability and stability of the **developer experience** by ensuring error overlays function as expected during development.

This commit **enhances the metadata routing system** in Next.js to correctly handle **static metadata files** (e.g., `favicon.ico`, `opengraph-image.png`) located within **dynamic routes**. It introduces an `isStatic` parameter to the `fillMetadataSegment` function, which, when `true`, replaces dynamic route segments with a fixed hyphen (`-`) placeholder in the generated path. This **feature enhancement** impacts the **App Router's metadata processing** in `next-core` and the `next` package's route generation and development bundler. The change ensures consistent URL generation and build output, guaranteeing that static metadata files in dynamic routes are always served from a predictable, fixed path, as verified by updated **e2e tests**.