Fix for issue #12

src/SaveRelationsBehavior.php

@@ -228,7 +228,7 @@ class SaveRelationsBehavior extends Behavior
     public function _saveModelRecord(ActiveRecord $model, ModelEvent $event, $pettyRelationName, $relationName)
     {
         $this->_validateRelationModel($pettyRelationName, $relationName, $model, $event);
-        if ($event->isValid && count($model->dirtyAttributes)) {
+        if ($event->isValid && (count($model->dirtyAttributes) || $model->isNewRecord)) {
             Yii::trace("Saving {$pettyRelationName} relation model", __METHOD__);
             $model->save(false);
         }
@@ -241,12 +241,7 @@ class SaveRelationsBehavior extends Behavior
      * @param ActiveRecord $relationModel
      * @param ModelEvent $event
      */
-    private function _validateRelationModel(
-        $pettyRelationName,
-        $relationName,
-        ActiveRecord $relationModel,
-        ModelEvent $event
-    )
+    private function _validateRelationModel($pettyRelationName, $relationName, ActiveRecord $relationModel, ModelEvent $event)
     {
         /** @var ActiveRecord $model */
         $model = $this->owner;
@@ -312,7 +307,7 @@ class SaveRelationsBehavior extends Behavior
                             $model->link($relationName, $actualModels[$key]);
                         }
                     } else { // Has one relation
-                        if ($this->_oldRelationValue[$relationName] != $model->{$relationName}) {
+                        if ($this->_oldRelationValue[$relationName] !== $model->{$relationName}) {
                             if ($model->{$relationName} instanceof ActiveRecord) {
                                 $model->link($relationName, $model->{$relationName});
                             } else {

tests/SaveRelationsBehaviorTest.php

@@ -6,8 +6,11 @@ namespace tests;
 use lhs\Yii2SaveRelationsBehavior\SaveRelationsBehavior;
 use RuntimeException;
 use tests\models\Company;
+use tests\models\DummyModel;
+use tests\models\DummyModelParent;
 use tests\models\Link;
 use tests\models\Project;
+use tests\models\ProjectLink;
 use tests\models\ProjectNoTransactions;
 use tests\models\User;
 use Yii;
@@ -33,6 +36,7 @@ class SaveRelationsBehaviorTest extends \PHPUnit_Framework_TestCase
         $db->createCommand()->dropTable('link_type')->execute();
         $db->createCommand()->dropTable('link')->execute();
         $db->createCommand()->dropTable('project_link')->execute();
+        $db->createCommand()->dropTable('dummy')->execute();
         parent::tearDown();
     }
 
@@ -94,6 +98,12 @@ class SaveRelationsBehaviorTest extends \PHPUnit_Framework_TestCase
             'PRIMARY KEY(project_id, user_id)'
         ])->execute();
 
+        // Dummy
+        $db->createCommand()->createTable('dummy', [
+            'id'        => $migration->primaryKey(),
+            'parent_id' => $migration->integer()
+        ])->execute();
+
         /**
          * Insert some data
          */
@@ -136,7 +146,6 @@ class SaveRelationsBehaviorTest extends \PHPUnit_Framework_TestCase
             [1, 4],
             [2, 2]
         ])->execute();
-
     }
 
     /**
@@ -427,4 +436,20 @@ class SaveRelationsBehaviorTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals(1, count($project->users), 'Project should have 1 users after assignment');
     }
 
+    public function testChangeHasOneRelationWithAnotherObject()
+    {
+        $dummy_a = new DummyModel();
+        $dummy_b = new DummyModel();
+        $dummy_a->save();
+        $dummy_b->save();
+        $dummy_a->children = $dummy_b;
+        $dummy_b->children = $dummy_a;
+        $this->assertTrue($dummy_a->save(), 'Dummy A could not be saved');
+        $this->assertTrue($dummy_b->save(), 'Dummy B could not be saved');
+        $dummy_c = new DummyModel();
+        //$this->assertTrue($dummy_c->save(), 'Dummy C could not be saved');
+        $dummy_a->children = $dummy_c;
+        $this->assertTrue($dummy_a->save(), 'Dummy A could not be saved');
+    }
+
 }