feat: support installation from custom NPM registry (#179)

copy .npmrc from GitHub workspace if it exists so that PNPM respects custom
registry configurations when self-installing

src/install-pnpm/run.ts

@@ -1,16 +1,16 @@
 import { addPath, exportVariable } from '@actions/core'
 import { spawn } from 'child_process'
-import { rm, writeFile, mkdir } from 'fs/promises'
+import { rm, writeFile, mkdir, copyFile } from 'fs/promises'
 import { readFileSync } from 'fs'
 import path from 'path'
 import { execPath } from 'process'
 import util from 'util'
-import * as yaml from 'yaml'
 import { Inputs } from '../inputs'
 import YAML from 'yaml'
 
 export async function runSelfInstaller(inputs: Inputs): Promise<number> {
   const { version, dest, packageJsonFile, standalone } = inputs
+  const { GITHUB_WORKSPACE } = process.env
 
   // prepare self install
   await rm(dest, { recursive: true, force: true })
@@ -20,6 +20,16 @@ export async function runSelfInstaller(inputs: Inputs): Promise<number> {
   // we have ensured the dest directory exists, we can write the file directly
   await writeFile(pkgJson, JSON.stringify({ private: true }))
 
+  // copy .npmrc if it exists to install from custom registry
+  if (GITHUB_WORKSPACE) {
+    try {
+      await copyFile(path.join(GITHUB_WORKSPACE, '.npmrc'), path.join(dest, '.npmrc'))
+    } catch (error) {
+      // Swallow error if .npmrc doesn't exist
+      if (!util.types.isNativeError(error) || !('code' in error) || error.code !== 'ENOENT') throw error
+    }
+  }
+
   // prepare target pnpm
   const target = await readTarget({ version, packageJsonFile, standalone })
   const cp = spawn(execPath, [path.join(__dirname, 'pnpm.cjs'), 'install', target, '--no-lockfile'], {
@@ -85,18 +95,10 @@ Otherwise, please specify the pnpm version in the action configuration.`)
   }
 
   if (typeof packageManager !== 'string') {
-    if (GITHUB_WORKSPACE) {
-      try {
-        const { lockfileVersion } = yaml.parse(readFileSync(path.join(GITHUB_WORKSPACE, 'pnpm-lock.yaml'), 'utf8'))
-        const version = getPnpmVersionFromLockfile(lockfileVersion);
-        return `${ standalone ? '@pnpm/exe' : 'pnpm' }@${version}`
-      } catch (error: unknown) {
-        throw new Error(`No pnpm version is specified.
+    throw new Error(`No pnpm version is specified.
 Please specify it by one of the following ways:
   - in the GitHub Action config with the key "version"
   - in the package.json with the key "packageManager"`)
-      }
-    }
   }
 
   if (!packageManager.startsWith('pnpm@')) {
@@ -110,21 +112,4 @@ Please specify it by one of the following ways:
   return packageManager
 }
 
-function getPnpmVersionFromLockfile(
-  lockfileVersion: string | undefined
-): string | undefined {
-  switch (true) {
-    case lockfileVersion === '5.3':
-      return 'latest-6';
-    case lockfileVersion === '5.4':
-      return 'latest-7';
-    case lockfileVersion === '6.0' || lockfileVersion === '6.1':
-      return 'latest-8';
-    case lockfileVersion === '7.0' || lockfileVersion === '9.0':
-      return 'latest-9';
-    default:
-      return undefined;
-  }
-}
-
 export default runSelfInstaller