fix(ui-sref): update ui-sref-active/eq info when params change

When ui-state dynamicly changes watchers, make sure to update the ui-sref-active/eq
Clear out old previous registered values.
Closes #2554

src/ng1/stateDirectives.ts

@@ -129,14 +129,16 @@ function $StateRefDirective($state, $timeout) {
       var def    = { state: ref.state, href: null, params: null, options: null };
       var type   = getTypeInfo(element);
       var active = uiSrefActive[1] || uiSrefActive[0];
+      var unlinkInfoFn = null;
 
       def.options = extend(defaultOpts(element, $state), attrs.uiSrefOpts ? scope.$eval(attrs.uiSrefOpts) : {});
 
       var update = function(val?) {
         if (val) def.params = angular.copy(val);
         def.href = $state.href(ref.state, def.params, def.options);
 
-        if (active) active.$$addStateInfo(ref.state, def.params);
+        if (unlinkInfoFn) unlinkInfoFn();
+        if (active) unlinkInfoFn = active.$$addStateInfo(ref.state, def.params);
         if (def.href !== null) attrs.$set(type.attr, def.href);
       };
 
@@ -185,10 +187,7 @@ function $StateRefDynamicDirective($state, $timeout) {
         def.state = group[0]; def.params = group[1]; def.options = group[2];
         def.href = $state.href(def.state, def.params, def.options);
 
-        if (unlinkInfoFn) {
-          unlinkInfoFn();
-          unlinkInfoFn = null;
-        }
+        if (unlinkInfoFn) unlinkInfoFn();
         if (active) unlinkInfoFn = active.$$addStateInfo(def.state, def.params);
         if (def.href) attrs.$set(type.attr, def.href);
       }

test/stateDirectivesSpec.js

@@ -615,6 +615,24 @@ describe('uiSrefActive', function() {
     expect(angular.element(template[0].querySelector('a')).attr('class')).toBe('');
   }));
 
+  it('should update in response to ui-sref param expression changes', inject(function($rootScope, $q, $compile, $state) {
+    el = angular.element('<div><a ui-sref="contacts.item.detail({ foo: fooId })" ui-sref-active="active">Contacts</a></div>');
+    template = $compile(el)($rootScope);
+    $rootScope.fooId = 'bar'
+    $rootScope.$digest();
+
+    expect(angular.element(template[0].querySelector('a')).attr('class')).toBe('');
+    $state.transitionTo('contacts.item.detail', { id: 5, foo: 'bar' });
+    $q.flush();
+    timeoutFlush();
+    expect(angular.element(template[0].querySelector('a')).attr('class')).toBe('active');
+
+    $rootScope.fooId = 'baz'
+    $q.flush();
+    timeoutFlush();
+    expect(angular.element(template[0].querySelector('a')).attr('class')).toBe('');
+  }));
+
   it('should match on child states', inject(function($rootScope, $q, $compile, $state) {
     template = $compile('<div><a ui-sref="contacts.item({ id: 1 })" ui-sref-active="active">Contacts</a></div>')($rootScope);
     $rootScope.$digest();