fix(windows): properly handle quoted args in event

Fixes: #1823

This mirrors the command parsing from run.js into the separate parser
for launching event driven shells.

lib/spawn.js

@@ -1,3 +1,4 @@
+const path = require('path');
 const utils = require('./utils');
 const merge = utils.merge;
 const bus = utils.bus;
@@ -10,26 +11,43 @@ module.exports = function spawnCommand(command, config, eventArgs) {
     stdio = ['pipe', process.stdout, process.stderr];
   }
 
+  const env = merge(process.env, { FILENAME: eventArgs[0] });
+
   var sh = 'sh';
   var shFlag = '-c';
+  var spawnOptions = {
+    env: merge(config.options.execOptions.env, env),
+    stdio: stdio,
+  };
 
-  if (utils.isWindows) {
-    sh = 'cmd';
-    shFlag = '/c';
+  if (!Array.isArray(command)) {
+    command = [command];
   }
 
+  if (utils.isWindows) {
+    // if the exec includes a forward slash, reverse it for windows compat
+    // but *only* apply to the first command, and none of the arguments.
+    // ref #1251 and #1236
+    command = command.map(executable => {
+      if (executable.indexOf('/') === -1) {
+        return executable;
+      }
 
-  if (!Array.isArray(command)) {
-    command = [command];
+      return  executable.split(' ').map((e, i) => {
+        if (i === 0) {
+          return path.normalize(e);
+        }
+        return e;
+      }).join(' ');
+    });
+    // taken from npm's cli: https://git.io/vNFD4
+    sh = process.env.comspec || 'cmd';
+    shFlag = '/d /s /c';
+    spawnOptions.windowsVerbatimArguments = true;
   }
 
   const args = command.join(' ');
-
-  const env = merge(process.env, { FILENAME: eventArgs[0] });
-  const child = spawn(sh, [shFlag, args], {
-    env: merge(config.options.execOptions.env, env),
-    stdio: stdio,
-  });
+  const child = spawn(sh, [shFlag, args], spawnOptions);
 
   if (config.required) {
     var emit = {