Implement dirty tracking and rollback of belongsTo relationships.

Issues emberjs#3696, emberjs#3045

packages/ember-data/lib/system/model/internal-model.js

@@ -98,7 +98,6 @@ InternalModel.prototype = {
   isEmpty: retrieveFromCurrentState('isEmpty'),
   isLoading: retrieveFromCurrentState('isLoading'),
   isLoaded: retrieveFromCurrentState('isLoaded'),
-  hasDirtyAttributes: retrieveFromCurrentState('hasDirtyAttributes'),
   isSaving: retrieveFromCurrentState('isSaving'),
   isDeleted: retrieveFromCurrentState('isDeleted'),
   isNew: retrieveFromCurrentState('isNew'),
@@ -327,6 +326,12 @@ InternalModel.prototype = {
     }
   },
 
+  rollback: function() {
+    this.rollbackAttributes();
+    this.rollbackRelationships();
+    this.send('rolledBack');
+  },
+
   rollbackAttributes: function() {
     var dirtyKeys = Object.keys(this._attributes);
 
@@ -462,6 +467,12 @@ InternalModel.prototype = {
     });
   },
 
+  rollbackRelationships: function() {
+    this.eachRelationship((name, relationship) => {
+      this._relationships.get(name).rollback();
+    });
+  },
+
   /**
     When a find request is triggered on the store, the user can optionally pass in
     attributes and relationships to be preloaded. These are meant to behave as if they

packages/ember-data/lib/system/model/model.js

@@ -122,6 +122,11 @@ var Model = Ember.Object.extend(Ember.Evented, {
   hasDirtyAttributes: Ember.computed('currentState.isDirty', function() {
     return this.get('currentState.isDirty');
   }),
+
+  hasDirtyRelationships: function() {
+    return this._internalModel._relationships.isDirty();
+  },
+
   /**
     If this property is `true` the record is in the `saving` state. A
     record enters the saving state when `save` is called, but the
@@ -629,6 +634,11 @@ var Model = Ember.Object.extend(Ember.Evented, {
     return diffData;
   },
 
+
+  rollback: function() {
+    this._internalModel.rollback();
+  },
+
   //TODO discuss with tomhuda about events/hooks
   //Bring back as hooks?
   /**
@@ -667,6 +677,12 @@ var Model = Ember.Object.extend(Ember.Evented, {
     this._internalModel.rollbackAttributes();
   },
 
+
+  rollbackRelationships: function() {
+    this._internalModel.rollbackRelationships();
+  },
+
+
   /*
     @method _createSnapshot
     @private

packages/ember-data/lib/system/model/states.js

@@ -274,6 +274,7 @@ var DirtyState = {
 
     rollback: function(internalModel) {
       internalModel.rollbackAttributes();
+      internalModel.rollbackRelationships();
       internalModel.triggerLater('ready');
     }
   },

packages/ember-data/lib/system/relationships/state/belongs-to.js

@@ -72,6 +72,8 @@ BelongsToRelationship.prototype.addRecord = function(newRecord) {
 
   this.inverseRecord = newRecord;
   this._super$addRecord(newRecord);
+
+  this.isDirty = this.canonicalState !== newRecord;
   this.record.notifyBelongsToChanged(this.key);
 };
 
@@ -138,3 +140,7 @@ BelongsToRelationship.prototype.getRecord = function() {
     return toReturn;
   }
 };
+
+BelongsToRelationship.prototype.rollback = function() {
+  this.setRecord(this.canonicalState);
+};

packages/ember-data/lib/system/relationships/state/create.js

@@ -36,3 +36,13 @@ Relationships.prototype.get = function(key) {
   }
   return relationships[key];
 };
+
+
+Relationships.prototype.isDirty = function() {
+  var relationshipsByName = get(this.record.type, 'relationshipsByName');
+  var keys = relationshipsByName._keys.toArray();
+
+  return keys.some((key) => {
+    return this.get(key).isDirty;
+  });
+};

packages/ember-data/lib/system/relationships/state/relationship.js

@@ -16,6 +16,7 @@ export default function Relationship(store, record, inverseKey, relationshipMeta
   this.linkPromise = null;
   this.meta = null;
   this.hasData = false;
+  this.isDirty = false;
 }
 
 Relationship.prototype = {
@@ -216,5 +217,9 @@ Relationship.prototype = {
 
   setHasData: function(value) {
     this.hasData = value;
+  },
+
+  rollback: function() {
+
   }
 };

packages/ember-data/tests/integration/relationships/belongs-to-test.js

@@ -984,3 +984,63 @@ test("Model's belongsTo relationship should be created during 'get' method", fun
     ok(user._internalModel._relationships.has('favouriteMessage'), "Newly created record with relationships in params passed in its constructor should have relationships");
   });
 });
+
+
+//
+test("relationship assignment is tracked", function () {
+  var book, author, anotherAuthor;
+
+  run(function() {
+    book = env.store.push({
+      data: {
+        id: '1',
+        type: 'book',
+        attributes: {
+          name: "A book with one true author?"
+        },
+        relationships: {
+          author: {
+            data: {
+              id: '2',
+              type: 'author'
+            }
+          }
+        }
+      }
+    });
+    author = env.store.push({
+      data: {
+        id: '2',
+        type: 'author',
+        attributes: {
+          name: 'Stanley'
+        }
+      }
+    });
+
+    anotherAuthor = env.store.push({
+      data: {
+        id: '3',
+        type: 'author',
+        attributes: {
+          name: 'Aaron'
+        }
+      }
+    });
+  });
+
+
+  run(function() {
+    equal(book.hasDirtyRelationships(), false, "Book should not have dirty relationships on load");
+
+    book.set('author', anotherAuthor);
+    equal(book.hasDirtyRelationships(), true, "Book has dirty relationships when new author is assigned");
+
+    equal(book.get('author'), anotherAuthor, "Book has another author assigned");
+
+    book.rollback();
+    equal(book.hasDirtyRelationships(), false, "Book does not have dirty relationships when new author assignment is rolled back");
+    equal(book.get('author'), author, "Book rolls back author");
+  });
+});
+