fix(path-extender-posix): keep lines between duplicate pnpm sections (#16227)

* fix(path-extender-posix): keep lines between duplicate pnpm sections

`@pnpm/os.env.path-extender-posix` replaced the pnpm section with a greedy
regex, so a shell config holding two `# pnpm` ... `# pnpm end` blocks lost
everything between the first opening marker and the last closing one.

pnpm/pnpm#15321 already fixed this for `pnpm setup`, but it did so in a
copy of the package inside `@pnpm/engine.pm.commands`, because the package
still lived in pnpm/components. Now that the package is in this repository,
move the fixed code and its tests back into it and let `pnpm setup` use the
package again. The copy is deleted.

The regression test for the published API is adapted from
pnpm/components#29 by Zelys, which proposed a non-greedy regex for the
same bug.

Closes https://github.com/pnpm/pnpm/issues/12282

Co-authored-by: Zelys <zelys@dfkhelper.com>
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix(path-extender-posix): prefer the block that sets proxyVarName

The duplicate-section selection looked for `<SECTION>_HOME`, which misses
the generated block when a caller's `proxyVarName` differs from its
section name. Pass `proxyVarName` through to `findSection`.

Also declare the section helpers after `updateShellConfig`, document the
`null` result, and reword the changeset.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Zelys <zelys@dfkhelper.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

.changeset/path-extender-posix-keeps-lines-between-sections.md

@@ -0,0 +1,6 @@
+---
+"@pnpm/os.env.path-extender-posix": patch
+"@pnpm/os.env.path-extender": patch
+---
+
+`addDirToPosixEnvPath` now keeps the lines between two `# pnpm` sections of a shell config file when it overwrites the pnpm section [#12282](https://github.com/pnpm/pnpm/issues/12282).

pnpm-lock.yaml

@@ -4178,9 +4178,6 @@ importers:
       symlink-dir:
         specifier: 'catalog:'
         version: 10.0.3
-      write-file-atomic:
-        specifier: 'catalog:'
-        version: 7.0.1
     devDependencies:
       '@jest/globals':
         specifier: 'catalog:'
@@ -4209,9 +4206,6 @@ importers:
       '@types/semver':
         specifier: 'catalog:'
         version: 7.8.0
-      '@types/write-file-atomic':
-        specifier: 'catalog:'
-        version: 4.0.3
 
   pnpm11/engine/runtime/bun-resolver:
     dependencies:
@@ -8000,6 +7994,9 @@ importers:
       '@pnpm/error':
         specifier: workspace:*
         version: link:../../../core/error
+      write-file-atomic:
+        specifier: 'catalog:'
+        version: 7.0.1
     devDependencies:
       '@jest/globals':
         specifier: 'catalog:'
@@ -8010,6 +8007,9 @@ importers:
       '@pnpm/prepare':
         specifier: workspace:*
         version: link:../../../__utils__/prepare
+      '@types/write-file-atomic':
+        specifier: 'catalog:'
+        version: 4.0.3
 
   pnpm11/os/env/path-extender-windows:
     dependencies:

pnpm11/engine/pm/commands/package.json

@@ -66,8 +66,7 @@
     "ramda": "catalog:",
     "render-help": "catalog:",
     "semver": "catalog:",
-    "symlink-dir": "catalog:",
-    "write-file-atomic": "catalog:"
+    "symlink-dir": "catalog:"
   },
   "peerDependencies": {
     "@pnpm/logger": "catalog:"
@@ -82,8 +81,7 @@
     "@pnpm/testing.mock-agent": "workspace:*",
     "@types/cross-spawn": "catalog:",
     "@types/ramda": "catalog:",
-    "@types/semver": "catalog:",
-    "@types/write-file-atomic": "catalog:"
+    "@types/semver": "catalog:"
   },
   "engines": {
     "node": ">=22.13"

pnpm11/engine/pm/commands/src/setup/pathExtender.ts

@@ -1,20 +0,0 @@
-import {
-  addDirToEnvPath as addDirToEnvPathExt,
-  type AddDirToEnvPathOpts,
-  type ConfigReport,
-  type PathExtenderReport,
-} from '@pnpm/os.env.path-extender'
-
-import { addDirToPosixEnvPath } from './pathExtenderPosix.js'
-
-export type { ConfigReport, PathExtenderReport }
-
-export async function addDirToEnvPath (
-  dir: string,
-  opts: AddDirToEnvPathOpts
-): Promise<PathExtenderReport> {
-  if (process.platform === 'win32') {
-    return addDirToEnvPathExt(dir, opts)
-  }
-  return addDirToPosixEnvPath(dir, opts)
-}

pnpm11/engine/pm/commands/src/setup/pathExtenderPosix.ts

@@ -1,346 +0,0 @@
-// cspell:ignore ZDOTDIR esep
-import fs from 'node:fs'
-import os from 'node:os'
-import path from 'node:path'
-import util from 'node:util'
-
-import { PnpmError } from '@pnpm/error'
-import writeFileAtomic from 'write-file-atomic'
-
-export class BadShellSectionError extends PnpmError {
-  public current: string
-  public wanted: string
-  constructor (opts: { configSectionName: string, wanted: string, current: string, configFile: string }) {
-    super('BAD_SHELL_SECTION', `The config file at "${opts.configFile}" already contains a ${opts.configSectionName} section but with other configuration`)
-    this.current = opts.current
-    this.wanted = opts.wanted
-  }
-}
-
-export type AddingPosition = 'start' | 'end'
-
-export interface AddDirToPosixEnvPathOpts {
-  proxyVarName?: string
-  proxyVarSubDir?: string
-  overwrite?: boolean
-  position?: AddingPosition
-  configSectionName: string
-}
-
-export type ConfigFileChangeType = 'skipped' | 'appended' | 'modified' | 'created'
-
-export interface ConfigReport {
-  path: string
-  changeType: ConfigFileChangeType
-}
-
-export interface PathExtenderPosixReport {
-  configFile: ConfigReport
-  oldSettings: string
-  newSettings: string
-}
-
-export async function addDirToPosixEnvPath (
-  dir: string,
-  opts: AddDirToPosixEnvPathOpts
-): Promise<PathExtenderPosixReport> {
-  const currentShell = detectCurrentShell()
-  return updateShell(currentShell, dir, opts)
-}
-
-function detectCurrentShell (): string | null {
-  if (process.env.ZSH_VERSION) return 'zsh'
-  if (process.env.BASH_VERSION) return 'bash'
-  if (process.env.FISH_VERSION) return 'fish'
-  if (process.env.NU_VERSION) return 'nu'
-  return typeof process.env.SHELL === 'string' ? path.basename(process.env.SHELL) : null
-}
-
-async function updateShell (
-  currentShell: string | null,
-  pnpmHomeDir: string,
-  opts: AddDirToPosixEnvPathOpts
-): Promise<PathExtenderPosixReport> {
-  switch (currentShell) {
-    case 'bash':
-    case 'zsh':
-    case 'ksh':
-    case 'dash':
-    case 'sh': {
-      return setupShell(currentShell, pnpmHomeDir, opts)
-    }
-    case 'fish': {
-      return setupFishShell(pnpmHomeDir, opts)
-    }
-    case 'nu': {
-      return setupNuShell(pnpmHomeDir, opts)
-    }
-  }
-  const supportedShellsMsg = 'Supported shell languages are bash, zsh, fish, ksh, dash, sh, and nushell.'
-  if (!currentShell) {
-    throw new PnpmError('UNKNOWN_SHELL', 'Could not infer shell type.', {
-      hint: `Set the SHELL environment variable to your active shell.\n${supportedShellsMsg}`,
-    })
-  }
-  throw new PnpmError('UNSUPPORTED_SHELL', `Can't setup configuration for "${currentShell}" shell`, {
-    hint: supportedShellsMsg,
-  })
-}
-
-async function setupShell (
-  shell: 'bash' | 'zsh' | 'ksh' | 'dash' | 'sh',
-  dir: string,
-  opts: AddDirToPosixEnvPathOpts
-): Promise<PathExtenderPosixReport> {
-  const configFile = getConfigFilePath(shell)
-  let newSettings: string
-  const _createPathValue = createPathValue.bind(null, opts.position ?? 'start')
-  if (opts.proxyVarName) {
-    const pathRef = opts.proxyVarSubDir ? `$${opts.proxyVarName}/${opts.proxyVarSubDir}` : `$${opts.proxyVarName}`
-    newSettings = `export ${opts.proxyVarName}="${dir}"
-case ":$PATH:" in
-  *":${pathRef}:"*) ;;
-  *) export PATH="${_createPathValue(pathRef)}" ;;
-esac`
-  } else {
-    newSettings = `case ":$PATH:" in
-  *":${dir}:"*) ;;
-  *) export PATH="${_createPathValue(dir)}" ;;
-esac`
-  }
-  const content = wrapSettings(opts.configSectionName, newSettings)
-  const { changeType, oldSettings } = await updateShellConfig(configFile, content, opts)
-  return {
-    configFile: {
-      path: configFile,
-      changeType,
-    },
-    oldSettings,
-    newSettings,
-  }
-}
-
-function getConfigFilePath (shell: 'bash' | 'zsh' | 'ksh' | 'dash' | 'sh'): string {
-  switch (shell) {
-    case 'zsh': return path.join((process.env.ZDOTDIR || os.homedir()), `.${shell}rc`)
-    case 'dash':
-    case 'sh': {
-      if (!process.env.ENV) {
-        throw new PnpmError('NO_SHELL_CONFIG', `Cannot find a config file for ${shell}. The ENV environment variable is not set.`)
-      }
-      return process.env.ENV
-    }
-    default: return path.join(os.homedir(), `.${shell}rc`)
-  }
-}
-
-function createPathValue (position: AddingPosition, dir: string): string {
-  return position === 'start'
-    ? `${dir}:$PATH`
-    : `$PATH:${dir}`
-}
-
-async function setupFishShell (dir: string, opts: AddDirToPosixEnvPathOpts): Promise<PathExtenderPosixReport> {
-  const configFile = path.join(os.homedir(), '.config/fish/config.fish')
-  let newSettings: string
-  const _createPathValue = createFishPathValue.bind(null, opts.position ?? 'start')
-  if (opts.proxyVarName) {
-    const pathRef = opts.proxyVarSubDir ? `$${opts.proxyVarName}/${opts.proxyVarSubDir}` : `$${opts.proxyVarName}`
-    const matchPattern = opts.proxyVarSubDir ? `"${pathRef}"` : pathRef
-    newSettings = `set -gx ${opts.proxyVarName} "${dir}"
-if not string match -q -- ${matchPattern} $PATH
-  set -gx PATH ${_createPathValue(pathRef)}
-end`
-  } else {
-    newSettings = `if not string match -q -- "${dir}" $PATH
-  set -gx PATH ${_createPathValue(dir)}
-end`
-  }
-  const content = wrapSettings(opts.configSectionName, newSettings)
-  const { changeType, oldSettings } = await updateShellConfig(configFile, content, opts)
-  return {
-    configFile: {
-      path: configFile,
-      changeType,
-    },
-    oldSettings,
-    newSettings,
-  }
-}
-
-async function setupNuShell (dir: string, opts: AddDirToPosixEnvPathOpts): Promise<PathExtenderPosixReport> {
-  const configFile = path.join(os.homedir(), '.config/nushell/env.nu')
-  let newSettings: string
-  const addingCommand = (opts.position ?? 'start') === 'start' ? 'prepend' : 'append'
-  if (opts.proxyVarName) {
-    const pathRef = opts.proxyVarSubDir
-      ? `($env.${opts.proxyVarName} | path join "${opts.proxyVarSubDir}")`
-      : `$env.${opts.proxyVarName}`
-    newSettings = `$env.${opts.proxyVarName} = "${dir}"
-$env.PATH = ($env.PATH | split row (char esep) | ${addingCommand} ${pathRef} )`
-  } else {
-    newSettings = `$env.PATH = ($env.PATH | split row (char esep) | ${addingCommand} ${dir} )`
-  }
-  const content = wrapSettings(opts.configSectionName, newSettings)
-  const { changeType, oldSettings } = await updateShellConfig(configFile, content, opts)
-  return {
-    configFile: {
-      path: configFile,
-      changeType,
-    },
-    oldSettings,
-    newSettings,
-  }
-}
-
-export function wrapSettings (sectionName: string, settings: string): string {
-  return `# ${sectionName}
-${settings}
-# ${sectionName} end`
-}
-
-function createFishPathValue (position: AddingPosition, dir: string): string {
-  return position === 'start'
-    ? `"${dir}" $PATH`
-    : `$PATH "${dir}"`
-}
-
-interface UpdateShellResult {
-  changeType: ConfigFileChangeType
-  oldSettings: string
-}
-
-export interface FoundSection {
-  start: number
-  end: number
-  inner: string
-  fullMatch: string
-}
-
-/**
- * Locate the `# <section>` ... `# <section> end` block.
- *
- * A valid section is bounded by an opening `# <section>` line and a closing
- * `# <section> end` line with no intermediate `# <section>` or `# <section> end`
- * markers. If several valid sections exist, the last one whose non-comment
- * lines reference both `PATH` and `<SECTION>_HOME` wins, then the last one
- * referencing `<SECTION>_HOME`, then the last one referencing `PATH`, then the
- * last section.
- */
-export function findSection (content: string, section: string): FoundSection | null {
-  if (!content) return null
-  const startMarker = `# ${section}`
-  const endMarker = `# ${section} end`
-
-  const sections: FoundSection[] = []
-  let lastStart: { lineStart: number, innerStart: number } | null = null
-  let offset = 0
-
-  const lines = content.split('\n')
-  for (let i = 0; i < lines.length; i++) {
-    const line = lines[i]
-    const lineStart = offset
-    const lineLengthWithNewline = i < lines.length - 1 ? line.length + 1 : line.length
-    offset += lineLengthWithNewline
-
-    const trimmed = line.replace(/[\r \t]+$/, '')
-    if (trimmed === startMarker) {
-      lastStart = {
-        lineStart,
-        innerStart: offset,
-      }
-    } else if (trimmed === endMarker) {
-      if (lastStart) {
-        const { lineStart: startOffset, innerStart } = lastStart
-        lastStart = null
-
-        const inner = content.slice(innerStart, lineStart).replace(/[\r\n]+$/, '')
-        const markerLen = line.replace(/[\r\n]+$/, '').length
-        const rangeEnd = lineStart + markerLen
-        sections.push({
-          start: startOffset,
-          end: rangeEnd,
-          inner,
-          fullMatch: content.slice(startOffset, rangeEnd),
-        })
-      }
-    }
-  }
-
-  if (sections.length === 0) return null
-  if (sections.length === 1) return sections[0]
-
-  const homeVar = `${section.toUpperCase()}_HOME`
-  const settings = sections.map(({ inner }) => stripComments(inner))
-  const predicates: Array<(text: string) => boolean> = [
-    (text) => text.includes('PATH') && text.includes(homeVar),
-    (text) => text.includes(homeVar),
-    (text) => text.includes('PATH'),
-  ]
-  for (const predicate of predicates) {
-    for (let i = sections.length - 1; i >= 0; i--) {
-      if (predicate(settings[i])) return sections[i]
-    }
-  }
-  return sections[sections.length - 1]
-}
-
-function stripComments (settings: string): string {
-  return settings.split('\n').filter((line) => !line.trimStart().startsWith('#')).join('\n')
-}
-
-export function replaceSection (originalContent: string, newSection: string, sectionName: string): string {
-  const section = findSection(originalContent, sectionName)
-  if (!section) return originalContent
-  return originalContent.slice(0, section.start) + newSection + originalContent.slice(section.end)
-}
-
-export async function updateShellConfig (
-  configFile: string,
-  newContent: string,
-  opts: AddDirToPosixEnvPathOpts
-): Promise<UpdateShellResult> {
-  await fs.promises.mkdir(path.dirname(configFile), { recursive: true })
-  try {
-    await fs.promises.writeFile(configFile, `${newContent}\n`, { encoding: 'utf8', flag: 'wx' })
-    return {
-      changeType: 'created',
-      oldSettings: '',
-    }
-  } catch (err: unknown) {
-    if (!util.types.isNativeError(err) || !('code' in err) || err.code !== 'EEXIST') {
-      throw err
-    }
-  }
-  const configContent = await fs.promises.readFile(configFile, 'utf8')
-  const section = findSection(configContent, opts.configSectionName)
-  if (!section) {
-    await fs.promises.appendFile(configFile, `\n${newContent}\n`, 'utf8')
-    return {
-      changeType: 'appended',
-      oldSettings: '',
-    }
-  }
-  const oldSettings = section.inner
-  const normalizedFullMatch = section.fullMatch.replace(/\r\n/g, '\n')
-  if (normalizedFullMatch !== newContent) {
-    if (!opts.overwrite) {
-      throw new BadShellSectionError({
-        configSectionName: opts.configSectionName,
-        current: section.fullMatch,
-        wanted: newContent,
-        configFile,
-      })
-    }
-    const newConfigContent = configContent.slice(0, section.start) + newContent + configContent.slice(section.end)
-    await writeFileAtomic(configFile, newConfigContent, 'utf8')
-    return {
-      changeType: 'modified',
-      oldSettings,
-    }
-  }
-  return {
-    changeType: 'skipped',
-    oldSettings,
-  }
-}

pnpm11/engine/pm/commands/src/setup/setup.ts

@@ -5,6 +5,11 @@ import path from 'node:path'
 import { detectIfCurrentPkgIsExecutable, packageManager } from '@pnpm/cli.meta'
 import { docsUrl } from '@pnpm/cli.utils'
 import { logger } from '@pnpm/logger'
+import {
+  addDirToEnvPath,
+  type ConfigReport,
+  type PathExtenderReport,
+} from '@pnpm/os.env.path-extender'
 import PATH from 'path-name'
 import { renderHelp } from 'render-help'
 
@@ -12,11 +17,6 @@ import {
   validateGHActionsEnvFileValues,
   writeGHActionsEnvFiles,
 } from './ghActionsEnv.js'
-import {
-  addDirToEnvPath,
-  type ConfigReport,
-  type PathExtenderReport,
-} from './pathExtender.js'
 
 export const rcOptionsTypes = (): Record<string, unknown> => ({})
 

pnpm11/engine/pm/commands/test/setup/setup.test.ts

@@ -5,7 +5,7 @@ import { afterEach, beforeEach, expect, jest, test } from '@jest/globals'
 import { PnpmError } from '@pnpm/error'
 import type { PathExtenderReport } from '@pnpm/os.env.path-extender'
 
-jest.unstable_mockModule('../../lib/setup/pathExtender.js', () => ({
+jest.unstable_mockModule('@pnpm/os.env.path-extender', () => ({
   addDirToEnvPath: jest.fn(),
 }))
 
@@ -33,7 +33,7 @@ jest.unstable_mockModule('fs', () => {
   }
 })
 
-const { addDirToEnvPath } = await import('../../lib/setup/pathExtender.js')
+const { addDirToEnvPath } = await import('@pnpm/os.env.path-extender')
 const { detectIfCurrentPkgIsExecutable } = await import('@pnpm/cli.meta')
 const { spawnSync } = await import('node:child_process')
 const { setup, LEGACY_HOME_DIR_SHIM_NAMES } = await import('@pnpm/engine.pm.commands')

pnpm11/os/env/path-extender-posix/package.json

@@ -36,12 +36,14 @@
     "prepublishOnly": "tsgo --build"
   },
   "dependencies": {
-    "@pnpm/error": "workspace:*"
+    "@pnpm/error": "workspace:*",
+    "write-file-atomic": "catalog:"
   },
   "devDependencies": {
     "@jest/globals": "catalog:",
     "@pnpm/os.env.path-extender-posix": "workspace:*",
-    "@pnpm/prepare": "workspace:*"
+    "@pnpm/prepare": "workspace:*",
+    "@types/write-file-atomic": "catalog:"
   },
   "engines": {
     "node": ">=22.13"

pnpm11/os/env/path-extender-posix/src/path-extender-posix.ts

@@ -1,14 +1,17 @@
+// cspell:ignore ZDOTDIR esep
 import fs from 'node:fs'
 import os from 'node:os'
 import path from 'node:path'
+import util from 'node:util'
 
 import { PnpmError } from '@pnpm/error'
+import writeFileAtomic from 'write-file-atomic'
 
-class BadShellSectionError extends PnpmError {
+export class BadShellSectionError extends PnpmError {
   public current: string
   public wanted: string
   constructor (opts: { configSectionName: string, wanted: string, current: string, configFile: string }) {
-    super('BAD_SHELL_SECTION', `The config file at "${opts.configFile} already contains a ${opts.configSectionName} section but with other configuration`)
+    super('BAD_SHELL_SECTION', `The config file at "${opts.configFile}" already contains a ${opts.configSectionName} section but with other configuration`)
     this.current = opts.current
     this.wanted = opts.wanted
   }
@@ -47,7 +50,7 @@ export async function addDirToPosixEnvPath (
   return updateShell(currentShell, dir, opts)
 }
 
-function detectCurrentShell () {
+function detectCurrentShell (): string | null {
   if (process.env.ZSH_VERSION) return 'zsh'
   if (process.env.BASH_VERSION) return 'bash'
   if (process.env.FISH_VERSION) return 'fish'
@@ -76,10 +79,11 @@ async function updateShell (
     }
   }
   const supportedShellsMsg = 'Supported shell languages are bash, zsh, fish, ksh, dash, sh, and nushell.'
-  if (!currentShell) throw new PnpmError('UNKNOWN_SHELL', 'Could not infer shell type.', {
-    hint: `Set the SHELL environment variable to your active shell.
-${supportedShellsMsg}`,
-  })
+  if (!currentShell) {
+    throw new PnpmError('UNKNOWN_SHELL', 'Could not infer shell type.', {
+      hint: `Set the SHELL environment variable to your active shell.\n${supportedShellsMsg}`,
+    })
+  }
   throw new PnpmError('UNSUPPORTED_SHELL', `Can't setup configuration for "${currentShell}" shell`, {
     hint: supportedShellsMsg,
   })
@@ -91,7 +95,7 @@ async function setupShell (
   opts: AddDirToPosixEnvPathOpts
 ): Promise<PathExtenderPosixReport> {
   const configFile = getConfigFilePath(shell)
-  let newSettings!: string
+  let newSettings: string
   const _createPathValue = createPathValue.bind(null, opts.position ?? 'start')
   if (opts.proxyVarName) {
     const pathRef = opts.proxyVarSubDir ? `$${opts.proxyVarName}/${opts.proxyVarSubDir}` : `$${opts.proxyVarName}`
@@ -132,7 +136,7 @@ function getConfigFilePath (shell: 'bash' | 'zsh' | 'ksh' | 'dash' | 'sh'): stri
   }
 }
 
-function createPathValue (position: AddingPosition, dir: string) {
+function createPathValue (position: AddingPosition, dir: string): string {
   return position === 'start'
     ? `${dir}:$PATH`
     : `$PATH:${dir}`
@@ -140,7 +144,7 @@ function createPathValue (position: AddingPosition, dir: string) {
 
 async function setupFishShell (dir: string, opts: AddDirToPosixEnvPathOpts): Promise<PathExtenderPosixReport> {
   const configFile = path.join(os.homedir(), '.config/fish/config.fish')
-  let newSettings!: string
+  let newSettings: string
   const _createPathValue = createFishPathValue.bind(null, opts.position ?? 'start')
   if (opts.proxyVarName) {
     const pathRef = opts.proxyVarSubDir ? `$${opts.proxyVarName}/${opts.proxyVarSubDir}` : `$${opts.proxyVarName}`
@@ -168,7 +172,7 @@ end`
 
 async function setupNuShell (dir: string, opts: AddDirToPosixEnvPathOpts): Promise<PathExtenderPosixReport> {
   const configFile = path.join(os.homedir(), '.config/nushell/env.nu')
-  let newSettings!: string
+  let newSettings: string
   const addingCommand = (opts.position ?? 'start') === 'start' ? 'prepend' : 'append'
   if (opts.proxyVarName) {
     const pathRef = opts.proxyVarSubDir
@@ -190,13 +194,14 @@ $env.PATH = ($env.PATH | split row (char esep) | ${addingCommand} ${pathRef} )`
     newSettings,
   }
 }
-function wrapSettings (sectionName: string, settings: string): string {
+
+export function wrapSettings (sectionName: string, settings: string): string {
   return `# ${sectionName}
 ${settings}
 # ${sectionName} end`
 }
 
-function createFishPathValue (position: AddingPosition, dir: string) {
+function createFishPathValue (position: AddingPosition, dir: string): string {
   return position === 'start'
     ? `"${dir}" $PATH`
     : `$PATH "${dir}"`
@@ -207,40 +212,45 @@ interface UpdateShellResult {
   oldSettings: string
 }
 
-async function updateShellConfig (
+export async function updateShellConfig (
   configFile: string,
   newContent: string,
   opts: AddDirToPosixEnvPathOpts
 ): Promise<UpdateShellResult> {
-  if (!fs.existsSync(configFile)) {
-    await fs.promises.mkdir(path.dirname(configFile), { recursive: true })
-    await fs.promises.writeFile(configFile, `${newContent}\n`, 'utf8')
+  await fs.promises.mkdir(path.dirname(configFile), { recursive: true })
+  try {
+    await fs.promises.writeFile(configFile, `${newContent}\n`, { encoding: 'utf8', flag: 'wx' })
     return {
       changeType: 'created',
       oldSettings: '',
     }
+  } catch (err: unknown) {
+    if (!util.types.isNativeError(err) || !('code' in err) || err.code !== 'EEXIST') {
+      throw err
+    }
   }
   const configContent = await fs.promises.readFile(configFile, 'utf8')
-  const match = new RegExp(`# ${opts.configSectionName}\n([\\s\\S]*)\n# ${opts.configSectionName} end`, 'g').exec(configContent)
-  if (!match) {
+  const section = findSection(configContent, opts.configSectionName, opts.proxyVarName)
+  if (!section) {
     await fs.promises.appendFile(configFile, `\n${newContent}\n`, 'utf8')
     return {
       changeType: 'appended',
       oldSettings: '',
     }
   }
-  const oldSettings = match[1]
-  if (match[0] !== newContent) {
+  const oldSettings = section.inner
+  const normalizedFullMatch = section.fullMatch.replace(/\r\n/g, '\n')
+  if (normalizedFullMatch !== newContent) {
     if (!opts.overwrite) {
       throw new BadShellSectionError({
         configSectionName: opts.configSectionName,
-        current: match[0],
+        current: section.fullMatch,
         wanted: newContent,
         configFile,
       })
     }
-    const newConfigContent = replaceSection(configContent, newContent, opts.configSectionName)
-    await fs.promises.writeFile(configFile, newConfigContent, 'utf8')
+    const newConfigContent = configContent.slice(0, section.start) + newContent + configContent.slice(section.end)
+    await writeFileAtomic(configFile, newConfigContent, 'utf8')
     return {
       changeType: 'modified',
       oldSettings,
@@ -252,6 +262,90 @@ async function updateShellConfig (
   }
 }
 
-function replaceSection (originalContent: string, newSection: string, sectionName: string): string {
-  return originalContent.replace(new RegExp(`# ${sectionName}[\\s\\S]*# ${sectionName} end`, 'g'), newSection)
+export interface FoundSection {
+  start: number
+  end: number
+  inner: string
+  fullMatch: string
+}
+
+/**
+ * Locate the `# <section>` ... `# <section> end` block.
+ *
+ * A valid section is bounded by an opening `# <section>` line and a closing
+ * `# <section> end` line with no intermediate `# <section>` or `# <section> end`
+ * markers. If several valid sections exist, the last one whose non-comment
+ * lines reference both `PATH` and `homeVar` wins, then the last one
+ * referencing `homeVar`, then the last one referencing `PATH`, then the last
+ * section. Returns `null` when the content holds no complete section.
+ */
+export function findSection (
+  content: string,
+  section: string,
+  homeVar = `${section.toUpperCase()}_HOME`
+): FoundSection | null {
+  if (!content) return null
+  const startMarker = `# ${section}`
+  const endMarker = `# ${section} end`
+
+  const sections: FoundSection[] = []
+  let lastStart: { lineStart: number, innerStart: number } | null = null
+  let offset = 0
+
+  const lines = content.split('\n')
+  for (let i = 0; i < lines.length; i++) {
+    const line = lines[i]
+    const lineStart = offset
+    const lineLengthWithNewline = i < lines.length - 1 ? line.length + 1 : line.length
+    offset += lineLengthWithNewline
+
+    const trimmed = line.replace(/[\r \t]+$/, '')
+    if (trimmed === startMarker) {
+      lastStart = {
+        lineStart,
+        innerStart: offset,
+      }
+    } else if (trimmed === endMarker) {
+      if (lastStart) {
+        const { lineStart: startOffset, innerStart } = lastStart
+        lastStart = null
+
+        const inner = content.slice(innerStart, lineStart).replace(/[\r\n]+$/, '')
+        const markerLen = line.replace(/[\r\n]+$/, '').length
+        const rangeEnd = lineStart + markerLen
+        sections.push({
+          start: startOffset,
+          end: rangeEnd,
+          inner,
+          fullMatch: content.slice(startOffset, rangeEnd),
+        })
+      }
+    }
+  }
+
+  if (sections.length === 0) return null
+  if (sections.length === 1) return sections[0]
+
+  const settings = sections.map(({ inner }) => stripComments(inner))
+  const predicates: Array<(text: string) => boolean> = [
+    (text) => text.includes('PATH') && text.includes(homeVar),
+    (text) => text.includes(homeVar),
+    (text) => text.includes('PATH'),
+  ]
+  for (const predicate of predicates) {
+    for (let i = sections.length - 1; i >= 0; i--) {
+      if (predicate(settings[i])) return sections[i]
+    }
+  }
+  return sections[sections.length - 1]
+}
+
+function stripComments (settings: string): string {
+  return settings.split('\n').filter((line) => !line.trimStart().startsWith('#')).join('\n')
+}
+
+export function replaceSection (originalContent: string, newSection: string, sectionName: string): string {
+  const section = findSection(originalContent, sectionName)
+  if (!section) return originalContent
+  return originalContent.slice(0, section.start) + newSection + originalContent.slice(section.end)
 }

pnpm11/os/env/path-extender-posix/test/path-extender-posix.test.ts

@@ -267,6 +267,40 @@ case ":$PATH:" in
 esac
 # pnpm end`)
   })
+  it('should keep the lines between two pnpm sections when overwriting (pnpm/pnpm#12282)', async () => {
+    const duplicateSection = `# pnpm
+export PNPM_HOME="duplicate_block"
+# pnpm end`
+    fs.writeFileSync(configFile, `# user config
+# pnpm
+export PNPM_HOME="old_home"
+case ":$PATH:" in
+  *":$PNPM_HOME:"*) ;;
+  *) export PATH="$PNPM_HOME:$PATH" ;;
+esac
+# pnpm end
+# content between sections that must not be deleted
+${duplicateSection}
+# after sections`, 'utf8')
+    const report = await addDirToPosixEnvPath(pnpmHomeDir, {
+      proxyVarName: 'PNPM_HOME',
+      overwrite: true,
+      configSectionName: 'pnpm',
+    })
+    expect(report.configFile?.changeType).toBe('modified')
+    const configContent = fs.readFileSync(configFile, 'utf8')
+    expect(configContent).toBe(`# user config
+# pnpm
+export PNPM_HOME="${pnpmHomeDir}"
+case ":$PATH:" in
+  *":$PNPM_HOME:"*) ;;
+  *) export PATH="$PNPM_HOME:$PATH" ;;
+esac
+# pnpm end
+# content between sections that must not be deleted
+${duplicateSection}
+# after sections`)
+  })
 })
 
 describe('Zsh', () => {

pnpm11/os/env/path-extender-posix/test/sections.test.ts

@@ -11,7 +11,7 @@ import {
   replaceSection,
   updateShellConfig,
   wrapSettings,
-} from '../../src/setup/pathExtenderPosix.js'
+} from '../src/path-extender-posix.js'
 
 function opts (overwrite: boolean): AddDirToPosixEnvPathOpts {
   return {
@@ -242,6 +242,28 @@ esac`)
     }
   })
 
+  test('prioritizes the block that sets proxyVarName when it differs from the section name', async () => {
+    const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'pnpm-posix-test-'))
+    try {
+      const configFile = path.join(dir, '.zshrc')
+      const generatedEnvBlock = wrapSettings('tool', 'export MY_HOME=/old\nexport PATH=$MY_HOME:$PATH')
+      const customPathBlock = wrapSettings('tool', 'export PATH=/custom/bin:$PATH')
+      fs.writeFileSync(configFile, `${generatedEnvBlock}\n\n${customPathBlock}\n`)
+
+      const newEnvBlock = wrapSettings('tool', 'export MY_HOME=/new\nexport PATH=$MY_HOME:$PATH')
+      const result = await updateShellConfig(configFile, newEnvBlock, {
+        configSectionName: 'tool',
+        proxyVarName: 'MY_HOME',
+        overwrite: true,
+      })
+
+      expect(result.oldSettings).toBe('export MY_HOME=/old\nexport PATH=$MY_HOME:$PATH')
+      expect(fs.readFileSync(configFile, 'utf8')).toBe(`${newEnvBlock}\n\n${customPathBlock}\n`)
+    } finally {
+      fs.rmSync(dir, { recursive: true, force: true })
+    }
+  })
+
   test('prioritizes generated env block over later custom path block', async () => {
     const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'pnpm-posix-test-'))
     try {