fix(isLocked): do not modify item

Previously setting a selected item as locked modified that item, this
could cause issues if the item was used outside of the directive.

This commit changes the directive to store the information internally
thus preventing it from interfering with external uses.

Closes angular-ui#1269 and angular-ui#514
Supersedes (and closes) angular-ui#1641 and angular-ui#952

src/uiSelectController.js

@@ -473,16 +473,51 @@ uis.controller('uiSelectCtrl',
     }
   };
 
-  ctrl.isLocked = function(itemScope, itemIndex) {
-      var isLocked, item = ctrl.selected[itemIndex];
+  // Set default function for locked choices - avoids unnecessary 
+  // logic if functionality is not being used
+  ctrl.isLocked = function () {
+    return false;
+  };
+
+  $scope.$watch(function () {
+    return angular.isDefined(ctrl.lockChoiceExpression) && ctrl.lockChoiceExpression !== "";
+  }, _initaliseLockedChoices);
+
+  function _initaliseLockedChoices() {
+    var lockedItems = [];
+
+    function _updateItemLocked(item, isLocked) {
+      var lockedItemIndex = lockedItems.indexOf(item);
+      if (isLocked && lockedItemIndex === -1) {
+        lockedItems.push(item);
+        }
 
-      if (item && !angular.isUndefined(ctrl.lockChoiceExpression)) {
-          isLocked = !!(itemScope.$eval(ctrl.lockChoiceExpression)); // force the boolean value
-          item._uiSelectChoiceLocked = isLocked; // store this for later reference
+      if (!isLocked && lockedItemIndex > -1) {
+        lockedItems.splice(lockedItemIndex, 0);
+      }
+    }
+
+    function _isItemlocked(item) {
+      return lockedItems.indexOf(item) > -1;
+    }
+
+    ctrl.isLocked = function (itemScope, itemIndex) {
+      var isLocked = false,
+          item = ctrl.selected[itemIndex];
+
+      if(item) {
+        if (itemScope) {
+          isLocked = !!(itemScope.$eval(ctrl.lockChoiceExpression));
+          _updateItemLocked(item, isLocked);
+        } else {
+          isLocked = _isItemlocked(item);
+        }
       }
 
       return isLocked;
-  };
+    };
+  }
+
 
   var sizeWatch = null;
   var updaterScheduled = false;

src/uiSelectMultipleDirective.js

@@ -37,10 +37,10 @@ uis.directive('uiSelectMultiple', ['uiSelectMinErr','$timeout', function(uiSelec
       // Remove item from multiple select
       ctrl.removeChoice = function(index){
 
-        var removedChoice = $select.selected[index];
+        // if the choice is locked, don't remove it
+        if($select.isLocked(null, index)) return false;
 
-        // if the choice is locked, can't remove it
-        if(removedChoice._uiSelectChoiceLocked) return;
+        var removedChoice = $select.selected[index];
 
         var locals = {};
         locals[$select.parserResult.itemName] = removedChoice;
@@ -59,6 +59,7 @@ uis.directive('uiSelectMultiple', ['uiSelectMinErr','$timeout', function(uiSelec
 
         ctrl.updateModel();
 
+        return true;
       };
 
       ctrl.getPlaceholder = function(){
@@ -246,11 +247,16 @@ uis.directive('uiSelectMultiple', ['uiSelectMinErr','$timeout', function(uiSelec
             case KEY.BACKSPACE:
               // Remove selected item and select previous/first
               if(~$selectMultiple.activeMatchIndex){
-                $selectMultiple.removeChoice(curr);
-                return prev;
-              }
-              // Select last item
-              else return last;
+                if($selectMultiple.removeChoice(curr)) {
+                  return prev;
+                } else {
+                  return curr;
+                }
+
+              } else {
+                // If nothing yet selected, select last item
+                return last;  
+              }              
               break;
             case KEY.DELETE:
               // Remove selected item and select next item

test/select.spec.js

@@ -1745,7 +1745,8 @@ describe('ui-select tests', function() {
 
     function createUiSelectMultiple(attrs) {
         var attrsHtml = '',
-            choicesAttrsHtml = '';
+            choicesAttrsHtml = '',
+            matchesAttrsHtml = '';
         if (attrs !== undefined) {
             if (attrs.disabled !== undefined) { attrsHtml += ' ng-disabled="' + attrs.disabled + '"'; }
             if (attrs.required !== undefined) { attrsHtml += ' ng-required="' + attrs.required + '"'; }
@@ -1756,11 +1757,12 @@ describe('ui-select tests', function() {
             if (attrs.taggingLabel !== undefined) { attrsHtml += ' tagging-label="' + attrs.taggingLabel + '"'; }
             if (attrs.inputId !== undefined) { attrsHtml += ' input-id="' + attrs.inputId + '"'; }
             if (attrs.groupBy !== undefined) { choicesAttrsHtml += ' group-by="' + attrs.groupBy + '"'; }
+            if (attrs.lockChoice !== undefined) { matchesAttrsHtml += ' ui-lock-choice="' + attrs.lockChoice + '"'; }
         }
 
         return compileTemplate(
             '<ui-select multiple ng-model="selection.selectedMultiple"' + attrsHtml + ' theme="bootstrap" style="width: 800px;"> \
-                <ui-select-match placeholder="Pick one...">{{$item.name}} &lt;{{$item.email}}&gt;</ui-select-match> \
+                <ui-select-match "' + matchesAttrsHtml + ' placeholder="Pick one...">{{$item.name}} &lt;{{$item.email}}&gt;</ui-select-match> \
                 <ui-select-choices repeat="person in people | filter: $select.search"' + choicesAttrsHtml + '> \
                   <div ng-bind-html="person.name | highlight: $select.search"></div> \
                   <div ng-bind-html="person.email | highlight: $select.search"></div> \
@@ -1922,6 +1924,37 @@ describe('ui-select tests', function() {
 
     });
 
+    it('should NOT remove highlighted match when pressing BACKSPACE key on a locked choice', function() {
+
+        scope.selection.selectedMultiple = [scope.people[4], scope.people[5], scope.people[6]]; //Wladimir, Samantha & Nicole
+        var el = createUiSelectMultiple({lockChoice: "$item.name == '" + scope.people[6].name + "'"});
+        var searchInput = el.find('.ui-select-search');
+
+        expect(isDropdownOpened(el)).toEqual(false);
+        triggerKeydown(searchInput, Key.Left);
+        triggerKeydown(searchInput, Key.Backspace);
+        expect(el.scope().$select.selected).toEqual([scope.people[4], scope.people[5], scope.people[6]]); //Wladimir, Samantha & Nicole
+
+        expect(el.scope().$selectMultiple.activeMatchIndex).toBe(scope.selection.selectedMultiple.length - 1);
+
+    });
+
+    it('should NOT remove highlighted match when pressing DELETE key on a locked choice', function() {
+
+        scope.selection.selectedMultiple = [scope.people[4], scope.people[5], scope.people[6]]; //Wladimir, Samantha & Nicole
+        var el = createUiSelectMultiple({lockChoice: "$item.name == '" + scope.people[6].name + "'"});
+        var searchInput = el.find('.ui-select-search');
+
+        expect(isDropdownOpened(el)).toEqual(false);
+        triggerKeydown(searchInput, Key.Left);
+        triggerKeydown(searchInput, Key.Delete);
+        expect(el.scope().$select.selected).toEqual([scope.people[4], scope.people[5], scope.people[6]]); //Wladimir, Samantha & Nicole
+
+        expect(el.scope().$selectMultiple.activeMatchIndex).toBe(scope.selection.selectedMultiple.length - 1);
+
+    });
+
+
     it('should move to last match when pressing LEFT key from search', function() {
 
         var el = createUiSelectMultiple();