Ben Gubler

This commit performs a **maintenance upgrade** of Biome to version 2.4.2 across all `create-next-app` templates. A significant **feature enhancement** is the introduction of **first-class Tailwind CSS support** within Biome configurations for relevant templates, achieved by enabling directive parsing and removing the `noUnknownAtRules` linter override. This ensures that new Next.js projects generated with `create-next-app` that utilize Biome and Tailwind will benefit from proper linting and formatting of Tailwind-specific syntax. The update also includes a general schema version bump for all `biome.json` files and updates the `@biomejs/biome` dependency in `index.ts`.

This commit introduces a significant **refactoring** of the **route discovery logic**, extracting duplicated collection, mapping, and processing into a unified `discoverRoutes()` API within new modules `build/route-discovery.ts` and `build/file-classifier.ts`. This streamlines the **build process**, **CLI type generation**, **development server bundler**, and **MCP tools** by replacing disparate implementations with a single, consistent interface. Additionally, it **fixes a bug** in the **dev bundler**'s `hasRootAppNotFound` detection and delivers **performance improvements** by parallelizing app file mapping and eliminating redundant directory traversals. The change results in a more robust, efficient, and maintainable system for handling route information across the application.

This commit **removes the automatic ESLint linting** that previously ran during the `next build` process, representing a **major architectural change** for Next.js 16. It streamlines the **Next.js build system** by eliminating the integrated linting step, giving developers explicit control over when linting occurs. The change involved removing lint-related code, including `verifyAndLint.ts` and `runLint` parameters, simplifying type checking, and updating **documentation** and numerous **example project `package.json` files** to reflect this new workflow. This impacts **developer workflow** by requiring manual lint execution and potentially improves **build performance**.

This commit is a **bug fix** that **improves TypeScript compatibility** for the **Next.js `typed-routes-validator` feature**. It **removes the `satisfies` keyword** from the generated type validation code within `packages/next/src/server/lib/router-utils/typegen.ts`, specifically in the `generateValidatorFile` function. This change ensures that the generated validator files are compatible with **older TypeScript versions**, preventing syntax errors for users not on the latest TS releases. The nature of this work is to **preserve broader compatibility** for the type generation utility. Corresponding **e2e tests** for the `typed-routes-validator` were updated in `test/e2e/app-dir/typed-routes-validator/typed-routes-validator.test.ts` to reflect the adjusted generated code and error messages.

This commit **fixes** an issue within the **Next.js TypeScript type declaration generation** by **removing redundant POSIX path normalization**. Specifically, the `writeAppTypeDeclarations` function in `packages/next/src/lib/typescript/writeAppTypeDeclarations.ts` now directly uses the original path for route type declarations, rather than applying unnecessary POSIX normalization to import directives. This **improves the accuracy and efficiency** of generated type declarations for application routes, ensuring import paths are correctly represented without superfluous processing.

This commit introduces a **new capability** to **`create-next-app`** by automatically running `next typegen` after a new Next.js project is created. This **feature enhancement** ensures that **route type definitions** are immediately available, significantly improving the **developer experience** for TypeScript users by providing proper type support from the start. A new `runTypegen()` helper is integrated into the main app creation flow (`createApp`) and the template installation process (`installTemplate`), with robust error handling to prevent interruptions during setup. This change streamlines the initial project configuration, making type-safe routing readily accessible.

This commit **fixes a bug** in the **type generation** for **Pages API routes** within Next.js. It corrects the return type definition in the validator, changing it from a specific `Promise<Response | void> | Response | void` union to a more general `unknown | Promise<unknown>`, which better accommodates various API handler implementations. This ensures that the generated types for API route handlers are accurate and flexible, impacting the `typegen.ts` utility and improving the overall type safety for developers using Pages API routes. A corresponding **test route** was updated to validate this change, ensuring the `NextApiHandler` type is correctly handled.

This commit **fixes a bug** in the **Typed Routes** feature where `next dev` generated incorrect, overly deep relative import paths within the `validator.ts` file. Previously, the `startWatcher` function in `packages/next/src/server/lib/router-utils/setup-dev-bundler.ts` pre-relativized page file paths and failed to pass the `validatorFilePath`, causing discrepancies with `next typegen` and `next build`. The **bug fix** modifies `setup-dev-bundler.ts` to correctly provide the `validatorFilePath` and use absolute file names when calling `createRouteTypesManifest`. This ensures `validator.ts` now produces shallow, consistent relative imports across `next dev`, `next typegen`, and `next build`, improving the reliability of type validation during development.

This commit implements a **bug fix** by modifying the default **Biome linter configuration** within several **`create-next-app` templates**. Specifically, the `noUnknownAtRules` rule is now entirely disabled, changing its setting from `warn` to `off` in the `biome.json` files for all JavaScript and TypeScript templates that include Tailwind CSS. This change prevents new Next.js projects from generating warnings or potential build failures due to unknown CSS at-rules, thereby improving the initial developer experience and reducing unnecessary linter noise. The affected templates include `app-tw-empty`, `app-tw`, `default-tw-empty`, and `default-tw`.

This commit provides a **bug fix** by updating the TypeScript configuration in several `create-next-app` templates to properly support **typed links** within the **Pages Router**. Specifically, it adds `".next/types/**/*.ts"` to the `include` array in `tsconfig.json` files for default, default-empty, default-tw, and default-tw-empty templates. This change ensures that newly created Pages Router projects correctly resolve types for links, a feature previously only functional in the App Router due to a forgotten template update. As a result, developers using `create-next-app` will now have full type-safety for their links in Pages Router applications.

This commit implements a **temporary bug fix** for the **Biome linter configuration** within **`create-next-app` templates** that utilize **Tailwind CSS**. It modifies the `biome.json` files across various `app-tw` and `default-tw` templates (for both JavaScript and TypeScript) to set the `noUnknownAtRules` rule to `warn`. This **workaround** prevents build failures caused by Biome incorrectly flagging Tailwind's custom at-rules as unknown, allowing projects to lint successfully until an official Biome update is released. The immediate impact is a smoother initial setup experience for new Next.js projects using Tailwind, as linting will now produce warnings instead of critical errors.

This commit introduces **path normalization** to the `getRelativePath` function within the **Next.js server's router utilities** (`packages/next/src/server/lib/router-utils/route-types-utils.ts`). This **bug fix** specifically addresses issues with path separators on **Windows environments**, ensuring that paths are correctly resolved regardless of the operating system. By normalizing paths, it prevents potential routing or file resolution errors for developers working on Windows, improving cross-platform compatibility for the **server-side routing logic**.

This commit introduces a **new feature** that enhances the **`next/navigation` module** by adding **type safety** to the `redirect()` and `permanentRedirect()` functions. When `config.typedRoutes` is enabled, this change provides compile-time validation for redirect paths, preventing common runtime errors from invalid routes. It involves new type generation logic within `router-utils/typegen.ts` and is thoroughly validated through comprehensive end-to-end and integration tests, ensuring correct behavior for both valid and invalid route scenarios. This significantly improves developer experience by catching routing mistakes earlier in the development cycle.

This commit **enhances the Next.js type generation system** to provide **typesafe linking for App Router API routes and Pages Router API routes**. It **extends the `generateLinkTypesFile` utility** within `packages/next/src/server/lib/router-utils/typegen.ts` to correctly include these API endpoints in the generated type definitions. This **new capability** ensures that developers receive compile-time checks when constructing links to API routes, significantly improving code reliability and developer experience within the **typed linking functionality**. New e2e tests were added to verify the correct generation and inclusion of these API routes in the type definitions.

This commit introduces an **optimization** to the **Next.js server-side routing utility's type generation process**. It **fixes** an issue where `AppRoutes`, `LayoutRoutes`, `ParamMap`, and various metadata types were unconditionally imported into the generated validator files. Now, these types are **conditionally imported** within `packages/next/src/server/lib/router-utils/typegen.ts` only when they are explicitly required by the validator, thereby **reducing unnecessary dependencies and improving build efficiency**. This change helps streamline the type generation, particularly for projects that may not utilize all routing features.

This commit **fixes a type definition bug** for **Next.js API routes** and **route handlers**, specifically addressing issue #82842. It updates the generated type definitions in `packages/next/src/server/lib/router-utils/typegen.ts` to correctly support `Promise<Response | void> | Response | void` as valid return types. This change ensures more accurate type checking for API endpoint return values, improving the developer experience by aligning type definitions with actual usage patterns.

This commit **fixes** an inaccuracy in the type definition for the `config.api.responseLimit` option within the **Next.js API configuration**. It updates the type in `packages/next/src/server/lib/router-utils/typegen.ts` to explicitly include `boolean` as a valid type, alongside existing options. This **maintenance** change addresses a limitation in JavaScript type inference, ensuring that developers can correctly set `responseLimit` to `false` without encountering type errors. The update improves the robustness and accuracy of the **API configuration types**, aligning them with actual runtime behavior.

This commit **updates the documentation** for the `next build` command, specifically clarifying the behavior and future status of the `--no-lint` option. It adds an important note to `docs/01-app/03-api-reference/06-cli/next.mdx` explaining that this option will eventually be removed. This **documentation enhancement** ensures users are aware of the upcoming deprecation, allowing them to adjust their build processes and avoid reliance on a feature that will no longer be supported. The change primarily impacts users consulting the **CLI reference documentation** for Next.js, providing crucial information for **maintenance** and future planning.

This commit **fixes outdated documentation** by updating references to the linting command from `next lint` to `eslint`. It specifically targets the **installation guide** (`docs/01-app/01-getting-started/01-installation.mdx`) and the **Cypress testing guide** (`docs/01-app/02-guides/testing/cypress.mdx`). This **documentation maintenance** ensures that users following these guides are provided with the correct and current command for running lint checks, thereby improving the accuracy of the **developer experience documentation**.

This commit provides a **bug fix** within the **`next-codemod`** package, specifically targeting the `next-lint-to-eslint-cli.ts` transform. It resolves a potential null access issue within the `updateExistingFlatConfig` function. By implementing optional chaining and providing a default empty array, the codemod now safely accesses properties of array elements, preventing runtime errors. This enhancement improves the **robustness and reliability** of the CLI transformation process, ensuring it can handle various configuration states without unexpected crashes.