correctly disconnecting associated objects from the source when associating with a new one

lib/sequelize/associations/has-one.js

@@ -5,6 +5,10 @@ var HasOne = module.exports = function(srcModel, targetModel, options) {
   this.source = srcModel
   this.target = targetModel
   this.options = options
+  this.accessors = {
+    get: Utils._.camelize('get_' + (this.options.as || this.target.tableName)),
+    set: Utils._.camelize('set_' + (this.options.as || this.target.tableName))
+  }
 }
 
 // the id is in the target table
@@ -14,15 +18,14 @@ HasOne.prototype.injectAttributes = function() {
   this.identifier = this.options.foreignKey || Utils._.underscoredIf(this.source.tableName + "Id", this.options.underscored)
   newAttributes[this.identifier] = { type: DataTypes.INTEGER }
   Utils._.extend(this.target.attributes, Utils.simplifyAttributes(newAttributes))
-
+  
   return this
 }
 
 HasOne.prototype.injectGetter = function(obj) {
-  var self     = this
-    , accessor = Utils._.camelize('get_' + (this.options.as || this.target.tableName))
+  var self = this
 
-  obj[accessor] = function() {
+  obj[this.accessors.get] = function() {
     var id    = obj.id
       , where = {}
     
@@ -34,12 +37,25 @@ HasOne.prototype.injectGetter = function(obj) {
 }
 
 HasOne.prototype.injectSetter = function(obj) {
-  var self     = this
-    , accessor = Utils._.camelize('set_' + (this.options.as || this.target.tableName))
+  var self = this
   
-  obj[accessor] = function(associatedObject) {
-    associatedObject[self.identifier] = this.id
-    return associatedObject.save()
+  obj[this.accessors.set] = function(associatedObject) {
+    var customEventEmitter = new Utils.CustomEventEmitter(function() {
+      obj[self.accessors.get]().on('success', function(oldObj) {
+        if(oldObj) {
+          oldObj[self.identifier] = null
+          oldObj.save()
+        }
+
+        associatedObject[self.identifier] = obj.id
+        associatedObject.save().on('success', function() {
+          customEventEmitter.emit('success', '')
+        }).on('failure', function(err) {
+          customEventEmitter.emit('failure', err)
+        })
+      })
+    })
+    return customEventEmitter
   }
   
   return this

lib/sequelize/utils.js

@@ -120,4 +120,7 @@ var Utils = module.exports = {
     })
     return result
   }
-}
\ No newline at end of file
+}
+
+Utils.CustomEventEmitter = function(fct) { fct() }
+Utils.addEventEmitter(Utils.CustomEventEmitter)
\ No newline at end of file

test/Model/has-one.js

@@ -70,5 +70,33 @@ module.exports = {
         })
       })
     })
+  },
+  'it should correctly unset the obsolete objects': function(exit) {
+    var User = sequelize.define('User' + parseInt(Math.random() * 99999999), { username: Sequelize.STRING })
+    var Task = sequelize.define('Task' + parseInt(Math.random() * 99999999), { title: Sequelize.STRING })
+    
+    User.hasOne(Task, {as: 'Task'})
+    
+    User.sync({force: true}).on('success', function() {
+      Task.sync({force: true}).on('success', function() {
+        User.create({username: 'name'}).on('success', function(user) {
+          Task.create({title: 'snafu'}).on('success', function(task) {
+            Task.create({title: 'another task'}).on('success', function(task2) {
+              user.setTask(task).on('success', function() {
+                user.getTask().on('success', function(_task) {
+                  assert.eql(task.title, _task.title)
+                  user.setTask(task2).on('success', function() {
+                    user.getTask().on('success', function(_task2) {
+                      assert.eql(task2.title, _task2.title)
+                      exit(function(){})
+                    })
+                  })
+                })
+              })
+            })
+          })
+        })
+      })
+    })
   }
 }
\ No newline at end of file