[Edit] Avoid extra commits

Avoid issuing extra commit calls from the Edit toolbar;
this can cause disruption of state from other views (such
as Fixed Position), WTD-881.

platform/commonUI/edit/src/representers/EditToolbar.js

@@ -34,14 +34,20 @@ define(
             // Update value for this property in all elements of the
             // selection which have this property.
             function updateProperties(property, value) {
+                var changed = false;
+
                 // Update property in a selected element
                 function updateProperty(selected) {
                     // Ignore selected elements which don't have this property
                     if (selected[property] !== undefined) {
                         // Check if this is a setter, or just assignable
                         if (typeof selected[property] === 'function') {
+                            changed =
+                                changed || (selected[property]() !== value);
                             selected[property](value);
                         } else {
+                            changed =
+                                changed || (selected[property] !== value);
                             selected[property] = value;
                         }
                     }
@@ -49,6 +55,9 @@ define(
 
                 // Update property in all selected elements
                 selection.forEach(updateProperty);
+
+                // Return whether or not anything changed
+                return changed;
             }
 
             // Look up the current value associated with a property
@@ -220,7 +229,7 @@ define(
                  * @param value the new value to convey to the selection
                  */
                 updateState: function (index, value) {
-                    updateProperties(properties[index], value);
+                    return updateProperties(properties[index], value);
                 }
             };
         }

platform/commonUI/edit/src/representers/EditToolbarRepresenter.js

@@ -51,11 +51,17 @@ define(
             // Update selection models to match changed toolbar state
             function updateState(state) {
                 // Update underlying state based on toolbar changes
-                (state || []).forEach(function (value, index) {
-                    toolbar.updateState(index, value);
-                });
-                // Commit the changes.
-                commit("Changes from toolbar.");
+                var changed = (state || []).map(function (value, index) {
+                    return toolbar.updateState(index, value);
+                }).reduce(function (a, b) {
+                    return a || b;
+                }, false);
+
+                // Only commit if something actually changed
+                if (changed) {
+                    // Commit the changes.
+                    commit("Changes from toolbar.");
+                }
             }
 
             // Initialize toolbar (expose object to parent scope)

platform/commonUI/edit/test/representers/EditToolbarRepresenterSpec.js

@@ -91,6 +91,32 @@ define(
 
                 // Should have updated the original object
                 expect(testObject.k).toEqual(456);
+
+                // Should have committed the change
+                expect(mockScope.commit).toHaveBeenCalled();
+            });
+
+            it("does not commit if nothing changed", function () {
+                var testObject = { k: 123 };
+
+                // Provide a view which has a toolbar
+                representer.represent({
+                    toolbar: { sections: [ { items: [ { property: 'k' } ] } ] }
+                });
+
+                // Update the selection
+                mockScope.selection.push(testObject);
+                expect(mockScope.$watchCollection.mostRecentCall.args[0])
+                    .toEqual('selection'); // Make sure we're using right watch
+                mockScope.$watchCollection.mostRecentCall.args[1]([testObject]);
+
+                // Invoke the first watch (assumed to be for toolbar state)
+                mockScope.$watchCollection.calls[0].args[1](
+                    mockScope.$parent.testToolbar.state
+                );
+
+                // Should have committed the change
+                expect(mockScope.commit).not.toHaveBeenCalled();
             });
 
         });

platform/commonUI/edit/test/representers/EditToolbarSpec.js

@@ -143,6 +143,15 @@ define(
                 expect(testABC.a).toHaveBeenCalledWith("new value");
             });
 
+            it("provides a return value describing update status", function () {
+                // Should return true if actually updated, otherwise false
+                var key;
+                toolbar.setSelection([ testABC ]);
+                key = toolbar.getStructure().sections[0].items[0].key;
+                expect(toolbar.updateState(key, testABC.a)).toBeFalsy();
+                expect(toolbar.updateState(key, "new value")).toBeTruthy();
+            });
+
             it("removes inapplicable items", function () {
                 // First, verify with all items
                 toolbar.setSelection([ testABC ]);