Simplify ipc use

Author: jdalton

src/utils/promise-fork.ts

@@ -1,29 +1,32 @@
 import path from 'node:path'
 import process from 'node:process'
 
-import { fork } from './promise-fork'
+import spawn from '@npmcli/promise-spawn'
+
+import { isObject } from '@socketsecurity/registry/lib/objects'
+
 import constants from '../constants'
 
-import type { ForkOptions, ForkResult } from './promise-fork'
-import type { Serializable } from 'node:child_process'
+type SpawnOption = Exclude<Parameters<typeof spawn>[2], undefined>
 
 const { abortSignal } = constants
 
-type ShadowNpmInstallOptions = ForkOptions & {
+type ShadowNpmInstallOptions = SpawnOption & {
   flags?: string[]
-  ipc?: Serializable
+  ipc?: object
 }
 
-export function shadowNpmInstall<O extends ShadowNpmInstallOptions>(
-  opts?: ShadowNpmInstallOptions
-) {
-  const { flags = [], ipc, ...forkOptions } = { __proto__: null, ...opts }
+export function shadowNpmInstall(opts?: ShadowNpmInstallOptions) {
+  const { flags = [], ipc, ...spawnOptions } = { __proto__: null, ...opts }
+  const useIpc = isObject(ipc)
   // Lazily access constants.ENV.
   const { SOCKET_CLI_DEBUG } = constants.ENV
-  const promise = fork(
-    // Lazily access constants.rootBinPath.
-    path.join(constants.rootBinPath, 'npm-cli.js'),
+  const promise = spawn(
+    // Lazily access constants.execPath.
+    constants.execPath,
     [
+      // Lazily access constants.rootBinPath.
+      path.join(constants.rootBinPath, 'npm-cli.js'),
       'install',
       // Even though the 'silent' flag is passed npm will still run through code
       // paths for 'audit' and 'fund' unless '--no-audit' and '--no-fund' flags
@@ -35,16 +38,26 @@ export function shadowNpmInstall<O extends ShadowNpmInstallOptions>(
     ],
     {
       signal: abortSignal,
-      // Lazily access constants.ENV.
-      stdio: SOCKET_CLI_DEBUG ? 'inherit' : 'ignore',
-      ...forkOptions,
+      // Set stdio to include 'ipc'.
+      // See https://github.com/nodejs/node/blob/v23.6.0/lib/child_process.js#L161-L166
+      // and https://github.com/nodejs/node/blob/v23.6.0/lib/internal/child_process.js#L238.
+      stdio: SOCKET_CLI_DEBUG
+        ? // 'inherit'
+          useIpc
+          ? [0, 1, 2, 'ipc']
+          : 'inherit'
+        : // 'ignore'
+          useIpc
+          ? ['ignore', 'ignore', 'ignore', 'ipc']
+          : 'ignore',
+      ...spawnOptions,
       env: {
         ...process.env,
-        ...forkOptions.env
+        ...spawnOptions.env
       }
     }
-  ) as ForkResult<O extends { stdioString: false } ? Buffer : string, undefined>
-  if (ipc) {
+  )
+  if (useIpc) {
     promise.process.send(ipc)
   }
   return promise