Handle empty responses from partials

Fixes #675

lib/handlebars/runtime.js

@@ -33,7 +33,7 @@ export function template(templateSpec, env) {
       // TODO : Check this for all inputs and the options handling (partial flag, etc). This feels
       // like there should be a common exec path
       var result = invokePartial.apply(this, arguments);
-      if (result) { return result; }
+      if (result != null) { return result; }
 
       var options = { helpers: helpers, partials: partials, data: data };
       partials[name] = env.compile(partial, { data: data !== undefined }, env);
@@ -42,7 +42,7 @@ export function template(templateSpec, env) {
   } else {
     invokePartialWrapper = function(partial, name /* , context, helpers, partials, data */) {
       var result = invokePartial.apply(this, arguments);
-      if (result) { return result; }
+      if (result != null) { return result; }
       throw new Exception("The partial " + name + " could not be compiled when running in runtime-only mode");
     };
   }

spec/partials.js

@@ -123,4 +123,10 @@ describe('partials', function() {
     var hash = {name:"Jeepers", another_dude:"Creepers"};
     shouldCompileToWithPartials(string, [hash, {}, {'+404/asdf?.bar':dude}], true, "Dudes: Jeepers", "Partials can use literal paths");
   });
+
+  it('should handle empty partial', function() {
+    var string = "Dudes: {{#dudes}}{{> dude}}{{/dudes}}";
+    var partial = "";
+    var hash = {dudes: [{name: "Yehuda", url: "http://yehuda"}, {name: "Alan", url: "http://alan"}]};
+    shouldCompileToWithPartials(string, [hash, {}, {dude: partial}], true, "Dudes: ");  });
 });