child_process: check fork args is an array

Optional fork args should be type-checked with same behaviour as the
equivalent argument to spawn.

PR-URL: #8454
Reviewed-by: Trevor Norris <trev.norris@gmail.com>

lib/child_process.js

@@ -525,6 +525,8 @@ exports.fork = function(modulePath /*, args, options*/) {
   if (Array.isArray(arguments[1])) {
     args = arguments[1];
     options = util._extend({}, arguments[2]);
+  } else if (arguments[1] && typeof arguments[1] !== 'object') {
+    throw new TypeError('Incorrect value of args option');
   } else {
     args = [];
     options = util._extend({}, arguments[1]);

test/simple/test-child-process-spawn-typeerror.js

@@ -22,8 +22,10 @@
 var assert = require('assert');
 var child_process = require('child_process');
 var spawn = child_process.spawn;
+var fork = child_process.fork;
 var execFile = child_process.execFile;
 var cmd = (process.platform === 'win32') ? 'dir' : 'ls';
+var empty = require('../common').fixturesDir + '/empty.js';
 
 
 // verify that args argument must be an array
@@ -45,3 +47,12 @@ assert.throws(function() {
 assert.doesNotThrow(function() {
   execFile(cmd, {});
 });
+
+// verify that fork has same argument parsing behaviour as spawn
+assert.throws(function() {
+  fork(empty, 'this is not an array');
+}, TypeError);
+
+assert.doesNotThrow(function() {
+  execFile(empty, {});
+});