fix: don't recursively switch to the same pnpm version (#8468)

.changeset/curvy-mice-learn.md

@@ -0,0 +1,5 @@
+---
+"@pnpm/env.path": minor
+---
+
+Add a new field to the return object: `updated`. When `false`, the prepended paths were already present in the path.

.changeset/lazy-fans-hunt.md

@@ -0,0 +1,5 @@
+---
+"pnpm": patch
+---
+
+Throw an exception if pnpm switches to the same version of itself.

env/path/src/index.ts

@@ -1,12 +1,27 @@
 import path from 'path'
 import PATH from 'path-name'
 
-export function prependDirsToPath (prependDirs: string[], env = process.env): { name: string, value: string } {
+export interface PrependDirsToPathResult {
+  name: string
+  value: string
+  updated: boolean
+}
+
+export function prependDirsToPath (prependDirs: string[], env = process.env): PrependDirsToPathResult {
+  const prepend = prependDirs.join(path.delimiter)
+  if (env[PATH] != null && (env[PATH] === prepend || env[PATH]!.startsWith(`${prepend}${path.delimiter}`))) {
+    return {
+      name: PATH,
+      value: env[PATH]!,
+      updated: false,
+    }
+  }
   return {
     name: PATH,
     value: [
-      ...prependDirs,
+      prepend,
       ...(env[PATH] != null ? [env[PATH]] : []),
     ].join(path.delimiter),
+    updated: true,
   }
 }

env/path/test/index.ts

@@ -6,9 +6,21 @@ test('prependDirsToPath', () => {
   expect(prependDirsToPath(['foo'], {})).toStrictEqual({
     name: PATH,
     value: 'foo',
+    updated: true,
   })
   expect(prependDirsToPath(['foo'], { [PATH]: 'bar' })).toStrictEqual({
     name: PATH,
     value: `foo${path.delimiter}bar`,
+    updated: true,
+  })
+  expect(prependDirsToPath(['foo', 'qar'], { [PATH]: `foo${path.delimiter}qar${path.delimiter}bar` })).toStrictEqual({
+    name: PATH,
+    value: `foo${path.delimiter}qar${path.delimiter}bar`,
+    updated: false,
+  })
+  expect(prependDirsToPath(['foo', 'qar'], { [PATH]: `foo${path.delimiter}qar` })).toStrictEqual({
+    name: PATH,
+    value: `foo${path.delimiter}qar`,
+    updated: false,
   })
 })

pnpm/src/switchCliVersion.ts

@@ -1,6 +1,7 @@
 import fs from 'fs'
 import path from 'path'
 import { type Config } from '@pnpm/config'
+import { PnpmError } from '@pnpm/error'
 import { globalWarn } from '@pnpm/logger'
 import { getCurrentPackageName, packageManager } from '@pnpm/cli-meta'
 import { prependDirsToPath } from '@pnpm/env.path'
@@ -37,7 +38,12 @@ export async function switchCliVersion (config: Config): Promise<void> {
       [`${pkgName}@${pm.version}`]
     )
   }
-  const pnpmEnv = prependDirsToPath([path.join(dir, 'bin')])
+  const wantedPnpmBinDir = path.join(dir, 'bin')
+  const pnpmEnv = prependDirsToPath([wantedPnpmBinDir])
+  if (!pnpmEnv.updated) {
+    // We throw this error to prevent an infinite recursive call of the same pnpm version.
+    throw new PnpmError('VERSION_SWITCH_FAIL', `Failed to switch pnpm to v${pm.version}. Looks like pnpm CLI is missing at "${wantedPnpmBinDir}" or is incorrect`)
+  }
   const { status } = spawn.sync('pnpm', process.argv.slice(2), {
     stdio: 'inherit',
     env: {