lib: improve option shell on child_process

doc/api/child_process.md

@@ -152,9 +152,11 @@ changes:
     **Default:** `null`.
   * `env` {Object} Environment key-value pairs. **Default:** `process.env`.
   * `encoding` {string} **Default:** `'utf8'`
-  * `shell` {string} Shell to execute the command with. See
-    [Shell Requirements][] and [Default Windows Shell][]. **Default:**
-    `'/bin/sh'` on Unix, `process.env.ComSpec` on Windows.
+  * `shell` {boolean|string|Array} If `true`, runs `command` inside of a shell.
+    Uses `'/bin/sh'` on Unix, and `process.env.ComSpec` on Windows. A different
+    shell can be specified as a string. Or specify a shell with arguments.
+    See [Shell Requirements][] and [Default Windows Shell][].
+    **Default:** `false` (no shell).
   * `timeout` {number} **Default:** `0`
   * `maxBuffer` {number} Largest amount of data in bytes allowed on stdout or
     stderr. If exceeded, the child process is terminated and any output is
@@ -241,6 +243,20 @@ async function lsExample() {
 lsExample();
 ```
 
+If `shell` is an `Array`, shell will be spawned with argument followed.
+
+```js
+const assert = require('assert');
+const { exec } = require('child_process');
+// https://docs.microsoft.com/windows-server/administration/windows-commands/cmd
+// exec cmd with no argument will displays
+// the version and copyright information of the operating system.
+exec('echo foo bar', { shell: ['cmd'] }, (error, stdout) => {
+  assert(error == null);
+  assert(!stdout.includes('foo') && !stdout.includes('bar'));
+});
+```
+
 ### `child_process.execFile(file[, args][, options][, callback])`
 <!-- YAML
 added: v0.1.91
@@ -268,10 +284,11 @@ changes:
     normally be created on Windows systems. **Default:** `false`.
   * `windowsVerbatimArguments` {boolean} No quoting or escaping of arguments is
     done on Windows. Ignored on Unix. **Default:** `false`.
-  * `shell` {boolean|string} If `true`, runs `command` inside of a shell. Uses
-    `'/bin/sh'` on Unix, and `process.env.ComSpec` on Windows. A different
-    shell can be specified as a string. See [Shell Requirements][] and
-    [Default Windows Shell][]. **Default:** `false` (no shell).
+  * `shell` {boolean|string|Array} If `true`, runs `command` inside of a shell.
+    Uses `'/bin/sh'` on Unix, and `process.env.ComSpec` on Windows. A different
+    shell can be specified as a string. Or specify a shell with arguments.
+    See [Shell Requirements][] and [Default Windows Shell][].
+    **Default:** `false` (no shell).
 * `callback` {Function} Called with the output when process terminates.
   * `error` {Error}
   * `stdout` {string|Buffer}
@@ -431,10 +448,11 @@ changes:
   * `serialization` {string} Specify the kind of serialization used for sending
     messages between processes. Possible values are `'json'` and `'advanced'`.
     See [Advanced Serialization][] for more details. **Default:** `'json'`.
-  * `shell` {boolean|string} If `true`, runs `command` inside of a shell. Uses
-    `'/bin/sh'` on Unix, and `process.env.ComSpec` on Windows. A different
-    shell can be specified as a string. See [Shell Requirements][] and
-    [Default Windows Shell][]. **Default:** `false` (no shell).
+  * `shell` {boolean|string|Array} If `true`, runs `command` inside of a shell.
+    Uses `'/bin/sh'` on Unix, and `process.env.ComSpec` on Windows. A different
+    shell can be specified as a string. Or specify a shell with arguments.
+    See [Shell Requirements][] and [Default Windows Shell][].
+    **Default:** `false` (no shell).
   * `windowsVerbatimArguments` {boolean} No quoting or escaping of arguments is
     done on Windows. Ignored on Unix. This is set to `true` automatically
     when `shell` is specified and is CMD. **Default:** `false`.
@@ -749,10 +767,11 @@ changes:
     **Default:** `'buffer'`.
   * `windowsHide` {boolean} Hide the subprocess console window that would
     normally be created on Windows systems. **Default:** `false`.
-  * `shell` {boolean|string} If `true`, runs `command` inside of a shell. Uses
-    `'/bin/sh'` on Unix, and `process.env.ComSpec` on Windows. A different
-    shell can be specified as a string. See [Shell Requirements][] and
-    [Default Windows Shell][]. **Default:** `false` (no shell).
+  * `shell` {boolean|string|Array} If `true`, runs `command` inside of a shell.
+    Uses `'/bin/sh'` on Unix, and `process.env.ComSpec` on Windows. A different
+    shell can be specified as a string. Or specify a shell with arguments.
+    See [Shell Requirements][] and [Default Windows Shell][].
+    **Default:** `false` (no shell).
 * Returns: {Buffer|string} The stdout from the command.
 
 The `child_process.execFileSync()` method is generally identical to
@@ -799,7 +818,8 @@ changes:
     be output to the parent process' stderr unless `stdio` is specified.
     **Default:** `'pipe'`.
   * `env` {Object} Environment key-value pairs. **Default:** `process.env`.
-  * `shell` {string} Shell to execute the command with. See
+  * `shell` {string|Array} Shell to execute the command with.
+    Or specify a shell with arguments. See
     [Shell Requirements][] and [Default Windows Shell][]. **Default:**
     `'/bin/sh'` on Unix, `process.env.ComSpec` on Windows.
   * `uid` {number} Sets the user identity of the process. (See setuid(2)).
@@ -878,10 +898,11 @@ changes:
     **Default:** `1024 * 1024`.
   * `encoding` {string} The encoding used for all stdio inputs and outputs.
     **Default:** `'buffer'`.
-  * `shell` {boolean|string} If `true`, runs `command` inside of a shell. Uses
-    `'/bin/sh'` on Unix, and `process.env.ComSpec` on Windows. A different
-    shell can be specified as a string. See [Shell Requirements][] and
-    [Default Windows Shell][]. **Default:** `false` (no shell).
+  * `shell` {boolean|string|Array} If `true`, runs `command` inside of a shell.
+    Uses `'/bin/sh'` on Unix, and `process.env.ComSpec` on Windows. A different
+    shell can be specified as a string. Or specify a shell with arguments.
+    See [Shell Requirements][] and [Default Windows Shell][].
+    **Default:** `false` (no shell).
   * `windowsVerbatimArguments` {boolean} No quoting or escaping of arguments is
     done on Windows. Ignored on Unix. This is set to `true` automatically
     when `shell` is specified and is CMD. **Default:** `false`.

lib/child_process.js

@@ -22,6 +22,7 @@
 'use strict';
 
 const {
+  Array,
   ArrayIsArray,
   Error,
   NumberIsInteger,
@@ -138,7 +139,8 @@ function normalizeExecArgs(command, options, callback) {
 
   // Make a shallow copy so we don't clobber the user's options object.
   options = { ...options };
-  options.shell = typeof options.shell === 'string' ? options.shell : true;
+  if (typeof options.shell !== 'string' && !Array.isArray(options.shell))
+    options.shell = true;
 
   return {
     file: command,
@@ -451,8 +453,15 @@ function normalizeSpawnArguments(file, args, options) {
   if (options.shell != null &&
       typeof options.shell !== 'boolean' &&
       typeof options.shell !== 'string') {
-    throw new ERR_INVALID_ARG_TYPE('options.shell',
-                                   ['boolean', 'string'], options.shell);
+    if (!Array.isArray(options.shell)) {
+      throw new ERR_INVALID_ARG_TYPE('options.shell',
+                                     ['boolean', 'string', 'Array'],
+                                     options.shell);
+    } else if (options.shell.length < 1) {
+      throw new ERR_INVALID_ARG_VALUE('options.shell',
+                                      options.shell,
+                                      'cannot be empty');
+    }
   }
 
   // Validate argv0, if present.
@@ -483,18 +492,26 @@ function normalizeSpawnArguments(file, args, options) {
     if (process.platform === 'win32') {
       if (typeof options.shell === 'string')
         file = options.shell;
+      else if (Array.isArray(options.shell))
+        file = options.shell[0];
       else
         file = process.env.comspec || 'cmd.exe';
       // '/d /s /c' is used only for cmd.exe.
       if (/^(?:.*\\)?cmd(?:\.exe)?$/i.test(file)) {
-        args = ['/d', '/s', '/c', `"${command}"`];
+        let parameters = ['/d', '/s', '/c'];
+        if (Array.isArray(options.shell)) {
+          parameters = options.shell.slice(1);
+        }
+        args = [...parameters, `"${command}"`];
         windowsVerbatimArguments = true;
       } else {
         args = ['-c', command];
       }
     } else {
       if (typeof options.shell === 'string')
         file = options.shell;
+      else if (Array.isArray(options.shell))
+        file = options.shell[0];
       else if (process.platform === 'android')
         file = '/system/bin/sh';
       else

test/parallel/test-child-process-exec-any-shells-windows.js

@@ -38,6 +38,7 @@ test('cmd');
 testCopy('cmd.exe', `${system32}\\cmd.exe`);
 test('cmd.exe');
 test('CMD');
+test(['cmd', '/d', '/s', '/c']);
 
 // Test PowerShell
 test('powershell');

test/parallel/test-child-process-spawnsync-validation-errors.js

@@ -98,7 +98,7 @@ if (!common.isWindows) {
   pass('shell', false);
   fail('shell', 0, invalidArgTypeError);
   fail('shell', 1, invalidArgTypeError);
-  fail('shell', [], invalidArgTypeError);
+  fail('shell', [], { code: 'ERR_INVALID_ARG_VALUE', name: 'TypeError' });
   fail('shell', {}, invalidArgTypeError);
   fail('shell', common.mustNotCall(), invalidArgTypeError);
 }