// @ts-check

/**

* Generates the list of Next.js modules that have a browser-specific variant,

* i.e. a `<module>.ts` (the default, used on the server and any unbundled

* runtime) paired with a sibling `<module>.browser.ts`. The browser bundle is

* aliased to the `.browser` variant by both bundlers:

*

* - webpack: packages/next/src/build/create-compiler-aliases.ts

* - Turbopack: crates/next-core/src/next_import_map.rs

*

* Both consumers read the generated lists produced here so the set stays in

* sync with the filesystem. CI runs this script followed by `git diff

* --exit-code` to ensure the committed lists are up to date.

*/

import { execFileSync } from 'child_process'

import { writeFileSync } from 'fs'

import { join, dirname } from 'path'

import { fileURLToPath } from 'url'

const __dirname = dirname(fileURLToPath(import.meta.url))

const repoRoot = join(__dirname, '..')

const srcRel = 'packages/next/src'

const tsOut = join(repoRoot, srcRel, 'build/browser-variant-modules.ts')

const rsOut = join(repoRoot, 'crates/next-core/src/browser_variant_modules.rs')

/** Git-tracked files (posix paths relative to the repo root) under a pathspec. */

function trackedFiles(pathspec) {

return execFileSync('git', ['ls-files', '--', pathspec], {

cwd: repoRoot,

encoding: 'utf8',

})

.split('\n')

.filter(Boolean)

}

/**

* Find `<module>.browser.{ts,tsx}` files that have a base `<module>.{ts,tsx}`

* sibling, returning posix module paths relative to `packages/next/src` without

* an extension (e.g. `client/components/unstable-rethrow`). Enumerated from

* git so generated output, ignored files, and build artifacts never leak in.

*/

function collectModules() {

const tracked = trackedFiles(srcRel)

const trackedSet = new Set(tracked)

/** @type {string[]} */

const modules = []

for (const file of tracked) {

const match = file.match(/^(.*)\.browser\.tsx?$/)

if (!match) continue

const stem = match[1]

if (!trackedSet.has(`${stem}.ts`) && !trackedSet.has(`${stem}.tsx`))

continue

modules.push(stem.slice(srcRel.length + 1))

}

return modules.sort()

}

function renderTs(modules) {

const entries = modules.map((m) => ` '${m}',`).join('\n')

return `// This file is @generated by \`pnpm generate-browser-variant-aliases\`.

// Do not edit by hand.

//

// Modules with a \`.browser\` sibling. The default module is aliased to its

// \`.browser\` variant for the browser bundle in

// \`packages/next/src/build/create-compiler-aliases.ts\`. Paths are relative to

// \`packages/next/dist\` (extension omitted).

export const browserVariantModules = [

${entries}

] as const

`

}

function renderRust(modules) {

const entries = modules.map((m) => ` "${m}",`).join('\n')

return `//! This file is @generated by \`pnpm generate-browser-variant-aliases\`.

//! Do not edit by hand.

//!

//! Modules with a \`.browser\` sibling. The default module is aliased to its

//! \`.browser\` variant for the browser bundle in

//! \`get_next_client_resolved_map\` (see \`next_import_map.rs\`). Paths are

//! relative to \`next/dist\` (extension omitted).

// rustfmt::skip keeps this list one-per-line (and matching the generator

// output) instead of collapsing short lists onto a single line.

#[rustfmt::skip]

pub static BROWSER_VARIANT_MODULES: &[&str] = &[

${entries}

];

`

}

const modules = collectModules()

writeFileSync(tsOut, renderTs(modules))

writeFileSync(rsOut, renderRust(modules))

console.log(

`Generated ${modules.length} browser-variant module(s):\n ${modules.join('\n ')}`

)