fix($compile): Allow literals in isolate scope references

When a component uses an isolate scope reference
and the the component is used with an object literal
a new object is created on every evaluation.
Therefore the compiler needs to compare
the values of the parent and the isolate scope
using object equality and not object reference
equality.

Fixes #5296.

Author: tbosch

src/ng/compile.js

@@ -1400,7 +1400,7 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
                 optional = (match[2] == '?'),
                 mode = match[1], // @, =, or &
                 lastValue,
-                parentGet, parentSet;
+                parentGet, parentSet, compare;
 
             isolateScope.$$isolateBindings[scopeName] = mode + attrName;
 
@@ -1423,6 +1423,11 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
                   return;
                 }
                 parentGet = $parse(attrs[attrName]);
+                if (parentGet.literal) {
+                  compare = equals;
+                } else {
+                  compare = function(a,b) { return a === b; };
+                }
                 parentSet = parentGet.assign || function() {
                   // reset the change, or we will throw this exception on every $digest
                   lastValue = isolateScope[scopeName] = parentGet(scope);
@@ -1433,10 +1438,9 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
                 lastValue = isolateScope[scopeName] = parentGet(scope);
                 isolateScope.$watch(function parentValueWatch() {
                   var parentValue = parentGet(scope);
-
-                  if (parentValue !== isolateScope[scopeName]) {
+                  if (!compare(parentValue, isolateScope[scopeName])) {
                     // we are out of sync and need to copy
-                    if (parentValue !== lastValue) {
+                    if (!compare(parentValue, lastValue)) {
                       // parent changed and it has precedence
                       isolateScope[scopeName] = parentValue;
                     } else {
@@ -1445,7 +1449,7 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
                     }
                   }
                   return lastValue = parentValue;
-                });
+                }, null, parentGet.literal);
                 break;
 
               case '&':

test/ng/compileSpec.js

@@ -2492,6 +2492,62 @@ describe('$compile', function() {
 
         expect(lastRefValueInParent).toBe('new');
       }));
+
+      describe('literal objects', function() {
+        it('should copy parent changes', inject(function() {
+          compile('<div><span my-component reference="{name: name}">');
+
+          $rootScope.name = 'a';
+          $rootScope.$apply();
+          expect(componentScope.reference).toEqual({name: 'a'});
+
+          $rootScope.name = 'b';
+          $rootScope.$apply();
+          expect(componentScope.reference).toEqual({name: 'b'});
+        }));
+
+        it('should not change the component when parent does not change', inject(function() {
+          compile('<div><span my-component reference="{name: name}">');
+
+          $rootScope.name = 'a';
+          $rootScope.$apply();
+          var lastComponentValue = componentScope.reference;
+          $rootScope.$apply();
+          expect(componentScope.reference).toBe(lastComponentValue);
+        }));
+
+        it('should complain when the component changes', inject(function() {
+          compile('<div><span my-component reference="{name: name}">');
+
+          $rootScope.name = 'a';
+          $rootScope.$apply();
+          componentScope.reference = {name: 'b'};
+          expect(function() {
+            $rootScope.$apply();
+          }).toThrowMinErr("$compile", "nonassign", "Expression '{name: name}' used with directive 'myComponent' is non-assignable!");
+
+        }));
+
+        it('should work for primitive literals', inject(function() {
+          test('1', 1);
+          test('null', null);
+          test('undefined', undefined);
+          test("'someString'", 'someString');
+
+
+          function test(literalString, literalValue) {
+            compile('<div><span my-component reference="'+literalString+'">');
+
+            $rootScope.$apply();
+            expect(componentScope.reference).toBe(literalValue);
+            dealoc(element);
+
+          }
+
+        }));
+
+      });
+
     });