child_process: add windowsHide option

This commit exposes the UV_PROCESS_WINDOWS_HIDE flag in Node
as a windowsHide option to the child_process methods. The
option is only applicable to Windows, and is ignored elsewhere.

Fixes: nodejs/node#15217
PR-URL: nodejs/node#15380
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/child_process.md

@@ -127,6 +127,10 @@ exec('"my script.cmd" a b', (err, stdout, stderr) => {
 ### child_process.exec(command[, options][, callback])
 <!-- YAML
 added: v0.1.90
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/15380
+    description: The `windowsHide` option is supported now.
 -->
 
 * `command` {string} The command to run, with space-separated arguments.
@@ -145,6 +149,8 @@ added: v0.1.90
   * `killSignal` {string|integer} **Default:** `'SIGTERM'`
   * `uid` {number} Sets the user identity of the process (see setuid(2)).
   * `gid` {number} Sets the group identity of the process (see setgid(2)).
+  * `windowsHide` {boolean} Hide the subprocess console window that would
+    normally be created on Windows systems. **Default:** `false`.
 * `callback` {Function} called with the output when process terminates.
   * `error` {Error}
   * `stdout` {string|Buffer}
@@ -238,6 +244,10 @@ lsExample();
 ### child_process.execFile(file[, args][, options][, callback])
 <!-- YAML
 added: v0.1.91
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/15380
+    description: The `windowsHide` option is supported now.
 -->
 
 * `file` {string} The name or path of the executable file to run.
@@ -253,6 +263,8 @@ added: v0.1.91
   * `killSignal` {string|integer} **Default:** `'SIGTERM'`
   * `uid` {number} Sets the user identity of the process (see setuid(2)).
   * `gid` {number} Sets the group identity of the process (see setgid(2)).
+  * `windowsHide` {boolean} Hide the subprocess console window that would
+    normally be created on Windows systems. **Default:** `false`.
 * `callback` {Function} Called with the output when process terminates.
   * `error` {Error}
   * `stdout` {string|Buffer}
@@ -364,6 +376,9 @@ supported by `child_process.fork()` and will be ignored if set.
 <!-- YAML
 added: v0.1.90
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/15380
+    description: The `windowsHide` option is supported now.
   - version: v6.4.0
     pr-url: https://github.com/nodejs/node/pull/7696
     description: The `argv0` option is supported now.
@@ -390,6 +405,8 @@ changes:
     `'/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).
+  * `windowsHide` {boolean} Hide the subprocess console window that would
+    normally be created on Windows systems. **Default:** `false`.
 * Returns: {ChildProcess}
 
 The `child_process.spawn()` method spawns a new process using the given
@@ -649,6 +666,9 @@ configuration at startup.
 <!-- YAML
 added: v0.11.12
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/15380
+    description: The `windowsHide` option is supported now.
   - version: v8.0.0
     pr-url: https://github.com/nodejs/node/pull/10653
     description: The `input` option can now be a `Uint8Array`.
@@ -678,6 +698,8 @@ changes:
     stderr. **Default:** `200*1024` If exceeded, the child process is terminated.
     See caveat at [`maxBuffer` and Unicode][].
   * `encoding` {string} The encoding used for all stdio inputs and outputs. **Default:** `'buffer'`
+  * `windowsHide` {boolean} Hide the subprocess console window that would
+    normally be created on Windows systems. **Default:** `false`.
 * Returns: {Buffer|string} The stdout from the command.
 
 The `child_process.execFileSync()` method is generally identical to
@@ -698,6 +720,9 @@ throw an [`Error`][] that will include the full result of the underlying
 <!-- YAML
 added: v0.11.12
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/15380
+    description: The `windowsHide` option is supported now.
   - version: v8.0.0
     pr-url: https://github.com/nodejs/node/pull/10653
     description: The `input` option can now be a `Uint8Array`.
@@ -727,6 +752,8 @@ changes:
     See caveat at [`maxBuffer` and Unicode][].
   * `encoding` {string} The encoding used for all stdio inputs and outputs.
     **Default:** `'buffer'`
+  * `windowsHide` {boolean} Hide the subprocess console window that would
+    normally be created on Windows systems. **Default:** `false`.
 * Returns: {Buffer|string} The stdout from the command.
 
 The `child_process.execSync()` method is generally identical to
@@ -749,6 +776,9 @@ execution.
 <!-- YAML
 added: v0.11.12
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/15380
+    description: The `windowsHide` option is supported now.
   - version: v8.0.0
     pr-url: https://github.com/nodejs/node/pull/10653
     description: The `input` option can now be a `Uint8Array`.
@@ -784,6 +814,8 @@ changes:
     `'/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).
+  * `windowsHide` {boolean} Hide the subprocess console window that would
+    normally be created on Windows systems. **Default:** `false`.
 * Returns: {Object}
   * `pid` {number} Pid of the child process.
   * `output` {Array} Array of results from stdio output.

lib/child_process.js

@@ -210,6 +210,7 @@ exports.execFile = function(file /*, args, options, callback*/) {
     gid: options.gid,
     uid: options.uid,
     shell: options.shell,
+    windowsHide: !!options.windowsHide,
     windowsVerbatimArguments: !!options.windowsVerbatimArguments
   });
 
@@ -428,6 +429,12 @@ function normalizeSpawnArguments(file, args, options) {
     throw new TypeError('"argv0" must be a string');
   }
 
+  // Validate windowsHide, if present.
+  if (options.windowsHide != null &&
+      typeof options.windowsHide !== 'boolean') {
+    throw new TypeError('"windowsHide" must be a boolean');
+  }
+
   // Validate windowsVerbatimArguments, if present.
   if (options.windowsVerbatimArguments != null &&
       typeof options.windowsVerbatimArguments !== 'boolean') {
@@ -493,6 +500,7 @@ var spawn = exports.spawn = function(/*file, args, options*/) {
     file: opts.file,
     args: opts.args,
     cwd: options.cwd,
+    windowsHide: !!options.windowsHide,
     windowsVerbatimArguments: !!options.windowsVerbatimArguments,
     detached: !!options.detached,
     envPairs: opts.envPairs,

src/env.h

@@ -292,6 +292,7 @@ class ModuleWrap;
   V(verify_error_string, "verifyError")                                       \
   V(version_string, "version")                                                \
   V(weight_string, "weight")                                                  \
+  V(windows_hide_string, "windowsHide")                                       \
   V(windows_verbatim_arguments_string, "windowsVerbatimArguments")            \
   V(wrap_string, "wrap")                                                      \
   V(writable_string, "writable")                                              \

src/process_wrap.cc

@@ -212,6 +212,13 @@ class ProcessWrap : public HandleWrap {
     // options.stdio
     ParseStdioOptions(env, js_options, &options);
 
+    // options.windowsHide
+    Local<String> windows_hide_key = env->windows_hide_string();
+
+    if (js_options->Get(windows_hide_key)->IsTrue()) {
+      options.flags |= UV_PROCESS_WINDOWS_HIDE;
+    }
+
     // options.windows_verbatim_arguments
     Local<String> windows_verbatim_arguments_key =
         env->windows_verbatim_arguments_string();

src/spawn_sync.cc

@@ -777,6 +777,11 @@ int SyncProcessRunner::ParseOptions(Local<Value> js_value) {
   if (js_options->Get(env()->detached_string())->BooleanValue())
     uv_process_options_.flags |= UV_PROCESS_DETACHED;
 
+  Local<String> win_hide = env()->windows_hide_string();
+
+  if (js_options->Get(win_hide)->BooleanValue())
+    uv_process_options_.flags |= UV_PROCESS_WINDOWS_HIDE;
+
   Local<String> wba = env()->windows_verbatim_arguments_string();
 
   if (js_options->Get(wba)->BooleanValue())

test/parallel/test-child-process-spawnsync-shell.js

@@ -66,6 +66,7 @@ assert.strictEqual(env.stdout.toString().trim(), 'buzz');
       assert.strictEqual(opts.options.shell, shell);
       assert.strictEqual(opts.options.file, opts.file);
       assert.deepStrictEqual(opts.options.args, opts.args);
+      assert.strictEqual(opts.options.windowsHide, undefined);
       assert.strictEqual(opts.options.windowsVerbatimArguments,
                          windowsVerbatim);
     });

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

@@ -124,6 +124,22 @@ if (!common.isWindows) {
   fail('argv0', common.mustNotCall(), err);
 }
 
+{
+  // Validate the windowsHide option
+  const err = /^TypeError: "windowsHide" must be a boolean$/;
+
+  pass('windowsHide', undefined);
+  pass('windowsHide', null);
+  pass('windowsHide', true);
+  pass('windowsHide', false);
+  fail('windowsHide', 0, err);
+  fail('windowsHide', 1, err);
+  fail('windowsHide', __dirname, err);
+  fail('windowsHide', [], err);
+  fail('windowsHide', {}, err);
+  fail('windowsHide', common.mustNotCall(), err);
+}
+
 {
   // Validate the windowsVerbatimArguments option
   const err = /^TypeError: "windowsVerbatimArguments" must be a boolean$/;

test/parallel/test-child-process-windows-hide.js

@@ -0,0 +1,52 @@
+// Flags: --expose_internals
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const cp = require('child_process');
+const internalCp = require('internal/child_process');
+const cmd = process.execPath;
+const args = ['-p', '42'];
+const options = { windowsHide: true };
+
+// Since windowsHide isn't really observable, monkey patch spawn() and
+// spawnSync() to verify that the flag is being passed through correctly.
+const originalSpawn = internalCp.ChildProcess.prototype.spawn;
+const originalSpawnSync = internalCp.spawnSync;
+
+internalCp.ChildProcess.prototype.spawn = common.mustCall(function(options) {
+  assert.strictEqual(options.windowsHide, true);
+  return originalSpawn.apply(this, arguments);
+}, 2);
+
+internalCp.spawnSync = common.mustCall(function(options) {
+  assert.strictEqual(options.options.windowsHide, true);
+  return originalSpawnSync.apply(this, arguments);
+});
+
+{
+  const child = cp.spawnSync(cmd, args, options);
+
+  assert.strictEqual(child.status, 0);
+  assert.strictEqual(child.signal, null);
+  assert.strictEqual(child.stdout.toString().trim(), '42');
+  assert.strictEqual(child.stderr.toString().trim(), '');
+}
+
+{
+  const child = cp.spawn(cmd, args, options);
+
+  child.on('exit', common.mustCall((code, signal) => {
+    assert.strictEqual(code, 0);
+    assert.strictEqual(signal, null);
+  }));
+}
+
+{
+  const callback = common.mustCall((err, stdout, stderr) => {
+    assert.ifError(err);
+    assert.strictEqual(stdout.trim(), '42');
+    assert.strictEqual(stderr.trim(), '');
+  });
+
+  cp.execFile(cmd, args, options, callback);
+}