complain if files are missing from concat step

dfreedm · dfreedm · commit 8a2583dba2fe · 2013-09-17T10:49:16.000-07:00
diff --git a/gruntfile.js b/gruntfile.js
@@ -42,7 +42,8 @@ module.exports = function(grunt) {
     concat_sourcemap: {
       Polymer: {
         options: {
-          sourcesContent: true
+          sourcesContent: true,
+          nonull: true
         },
         files: {
           'polymer.concat.js': Polymer
