refactor(node): normalize line endings at the file read boundary

Adds readTextFile/readTextFileSync (CRLF/CR -> LF) next to the raw
retrying readFile and switches the markdown-source readers to them
(content loader, dynamic route templates, local search, includes).
Raw reads stay in place where bytes must be preserved (serve, init
scaffolding).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

__tests__/unit/node/utils/fs.test.ts

@@ -0,0 +1,34 @@
+import { mkdtemp, rm, writeFile } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import path from 'node:path'
+import { readFile, readTextFile, readTextFileSync } from 'node/utils/fs'
+
+describe('node/utils/fs', () => {
+  let root: string
+
+  beforeEach(async () => {
+    root = await mkdtemp(path.join(tmpdir(), 'vitepress-fs-'))
+  })
+
+  afterEach(async () => {
+    await rm(root, { recursive: true, force: true })
+  })
+
+  test('readFile keeps line endings as is', async () => {
+    const file = path.join(root, 'crlf.txt')
+    await writeFile(file, 'a\r\nb\rc\nd')
+    expect(await readFile(file)).toBe('a\r\nb\rc\nd')
+  })
+
+  test('readTextFile normalizes CRLF and CR to LF', async () => {
+    const file = path.join(root, 'crlf.txt')
+    await writeFile(file, 'a\r\nb\rc\nd')
+    expect(await readTextFile(file)).toBe('a\nb\nc\nd')
+  })
+
+  test('readTextFileSync normalizes CRLF and CR to LF', async () => {
+    const file = path.join(root, 'crlf.txt')
+    await writeFile(file, 'a\r\nb\rc\nd')
+    expect(readTextFileSync(file)).toBe('a\nb\nc\nd')
+  })
+})

src/node/contentLoader.ts

@@ -9,7 +9,7 @@ import {
   mergeMarkdownLocales
 } from './markdown/markdown'
 import type { Awaitable, MarkdownEnv } from './shared'
-import { readFile } from './utils/fs'
+import { readTextFile } from './utils/fs'
 import { glob, normalizeGlob, type GlobOptions } from './utils/glob'
 
 export interface ContentOptions<T = ContentData[]> {
@@ -122,7 +122,7 @@ export function createContentLoader<T = ContentData[]>(
 
           if (cached && timestamp === cached.timestamp) return cached.data
 
-          const src = await readFile(file)
+          const src = await readTextFile(file)
 
           const renderExcerpt = options.excerpt
           const { data: frontmatter, excerpt } = matter(

src/node/plugins/dynamicRoutesPlugin.ts

@@ -12,7 +12,7 @@ import {
 } from 'vite'
 import type { Awaitable } from '../shared'
 import { type SiteConfig, type UserConfig } from '../siteConfig'
-import { readFile } from '../utils/fs'
+import { readTextFile } from '../utils/fs'
 import { glob, normalizeGlob, type GlobOptions } from '../utils/glob'
 import { ModuleGraph } from '../utils/moduleGraph'
 import { resolveRewrites } from './rewritesPlugin'
@@ -158,7 +158,7 @@ export const dynamicRoutesPlugin = async (
           moduleGraph.add(id, [routeFile])
           moduleGraph.add(routeFile, [matched.loaderPath])
 
-          let baseContent = await readFile(routeFile)
+          let baseContent = await readTextFile(routeFile)
 
           // inject raw content
           // this is intended for integration with CMS

src/node/plugins/localSearchPlugin.ts

@@ -7,7 +7,7 @@ import type { SiteConfig } from '../config'
 import type { DefaultTheme } from '../defaultTheme'
 import { createMarkdownRenderer } from '../markdown/markdown'
 import { getLocaleForPath, slash, type MarkdownEnv } from '../shared'
-import { readFile } from '../utils/fs'
+import { readTextFile } from '../utils/fs'
 import { processIncludes } from '../utils/processIncludes'
 
 const debug = createDebug('vitepress:local-search')
@@ -55,7 +55,7 @@ export async function localSearchPlugin(
     const { srcDir, cleanUrls = false } = siteConfig
     const relativePath = slash(path.relative(srcDir, file))
     const env: MarkdownEnv = { path: file, relativePath, cleanUrls }
-    const raw = await readFile(file).catch((e) => {
+    const raw = await readTextFile(file).catch((e) => {
       if (e.code === 'ENOENT') {
         debug(`File not found: ${file}`)
         return ''

src/node/utils/fs.ts

@@ -1,7 +1,9 @@
+import fs from 'node:fs'
 import { readFile as fsReadFile } from 'node:fs/promises'
 import { setTimeout } from 'node:timers/promises'
 
 const retryCodes = new Set(['EMFILE', 'ENFILE'])
+const newlineRE = /\r\n?/g
 
 /**
  * Reads a file as utf8, retrying with backoff when the process is
@@ -18,3 +20,17 @@ export async function readFile(file: string): Promise<string> {
     }
   }
 }
+
+/**
+ * Reads a text file like `readFile`, with line endings normalized to `\n`.
+ */
+export async function readTextFile(file: string): Promise<string> {
+  return (await readFile(file)).replace(newlineRE, '\n')
+}
+
+/**
+ * Synchronous `readTextFile`, for use inside synchronous markdown-it rules.
+ */
+export function readTextFileSync(file: string): string {
+  return fs.readFileSync(file, 'utf8').replace(newlineRE, '\n')
+}

src/node/utils/processIncludes.ts

@@ -3,7 +3,7 @@ import { replaceAsync, type MarkdownItAsync } from 'markdown-it-async'
 import path from 'node:path'
 import { findRegion } from '../markdown/plugins/snippet'
 import { slash, type MarkdownEnv } from '../shared'
-import { readFile } from './fs'
+import { readTextFile } from './fs'
 
 export function processIncludes(
   md: MarkdownItAsync,
@@ -41,7 +41,7 @@ export function processIncludes(
     // chain are cycles, the same file may still be included by siblings
     if (includePath === file || ancestors.includes(includePath)) return m
 
-    let content = await readFile(includePath)
+    let content = await readTextFile(includePath)
 
     if (region) {
       const [regionName] = region