Do not lookup pathed helpers on the helper stack

Fixes #764

Author: kpdecker

lib/handlebars/compiler/compiler.js

@@ -280,7 +280,7 @@ Compiler.prototype = {
       id.falsy = true;
 
       this.ID(id);
-      this.opcode('invokeHelper', params.length, id.original, sexpr.isRoot);
+      this.opcode('invokeHelper', params.length, id.original, id.isSimple, sexpr.isRoot);
     }
   },
 

lib/handlebars/compiler/javascript-compiler.js

@@ -369,7 +369,7 @@ JavaScriptCompiler.prototype = {
           return ' != null ? ' + lookup + ' : ' + current;
         } else {
           // Otherwise we can use generic falsy handling
-          return ' != null && ' + lookup;
+          return (falsy ? ' && ' : ' != null && ') + lookup;
         }
       }, true);
     }
@@ -527,19 +527,18 @@ JavaScriptCompiler.prototype = {
   // and pushes the helper's return value onto the stack.
   //
   // If the helper is not found, `helperMissing` is called.
-  invokeHelper: function(paramSize, name, isRoot) {
+  invokeHelper: function(paramSize, name, isSimple, isRoot) {
     this.aliases.helperMissing = 'helpers.helperMissing';
-    this.useRegister('helper');
 
     var nonHelper = this.popStack();
     var helper = this.setupHelper(paramSize, name);
 
-    var lookup = 'helper = ' + helper.name + ' || ' + nonHelper + ' || helperMissing';
+    var lookup = (isSimple ? helper.name + ' || ' : '') + nonHelper + ' || helperMissing';
     if (helper.paramsInit) {
       lookup += ',' + helper.paramsInit;
     }
 
-    this.push('(' + lookup + ',helper.call(' + helper.callParams + '))');
+    this.push('((' + lookup + ').call(' + helper.callParams + '))');
 
     // Always flush subexpressions. This is both to prevent the compounding size issue that
     // occurs when the code has to be duplicated for inlining and also to prevent errors

spec/helpers.js

@@ -158,6 +158,22 @@ describe('helpers', function() {
     shouldCompileTo(messageString, [rootMessage, { list: list }], "<p>Nobody&#x27;s here</p>", "the context of an inverse is the parent of the block");
   });
 
+  it('pathed lambas with parameters', function() {
+    var hash = {
+      helper: function() {
+        return 'winning';
+      }
+    };
+    hash.hash = hash;
+    var helpers = {
+      './helper': function() {
+        return 'fail';
+      }
+    };
+    shouldCompileTo('{{./helper 1}}', [hash, helpers], 'winning');
+    shouldCompileTo('{{hash/helper 1}}', [hash, helpers], 'winning');
+  });
+
   describe("helpers hash", function() {
     it("providing a helpers hash", function() {
       shouldCompileTo("Goodbye {{cruel}} {{world}}!", [{cruel: "cruel"}, {world: function() { return "world"; }}], "Goodbye cruel world!",