Merge remote-tracking branch 'upstream/master'

swagger-api/swagger-js@dd8f847c8e

Author: Miroslav Bajtoš

lib/schema-markup.js

@@ -211,6 +211,10 @@ function schemaToHTML(name, schema, models, modelPropertyMacro) {
   if(typeof schema.$ref === 'string') {
     name = Helpers.simpleRef(schema.$ref);
     schema = models[name];
+    if(typeof schema === 'undefined')
+    {
+      return strongOpen + name + ' is not defined!' + strongClose;
+    }
   }
 
   if(typeof name !== 'string') {