Add test exposing UnitOfWork merge bug

tests/Doctrine/Tests/ORM/Functional/MergeCompositeToOneKeyTest.php

@@ -0,0 +1,62 @@
+<?php
+
+namespace Doctrine\Tests\ORM\Functional;
+
+use Doctrine\ORM\Mapping\JoinColumn;
+
+class MergeCompositeToOneKeyTest extends \Doctrine\Tests\OrmFunctionalTestCase
+{
+    protected function setUp()
+    {
+        parent::setUp();
+        $this->_schemaTool->createSchema(array(
+            $this->_em->getClassMetadata(__NAMESPACE__ . '\MergeCompositeToOneKeyCountry'),
+            $this->_em->getClassMetadata(__NAMESPACE__ . '\MergeCompositeToOneKeyState'),
+        ));
+    }
+
+    public function testIssue()
+    {
+        $country = new MergeCompositeToOneKeyCountry();
+        $country->country = 'US';
+        $state = new MergeCompositeToOneKeyState();
+        $state->state = 'CA';
+        $state->country = $country;
+
+        $this->_em->merge($country);
+        $this->_em->merge($state);
+    }
+}
+
+/**
+ * @Entity
+ */
+class MergeCompositeToOneKeyCountry
+{
+    /**
+     * @Id
+     * @Column(type="string", name="country")
+     * @GeneratedValue(strategy="NONE")
+     */
+    public $country;
+}
+
+/**
+ * @Entity
+  */
+class MergeCompositeToOneKeyState
+{
+    /**
+     * @Id
+     * @Column(type="string")
+     * @GeneratedValue(strategy="NONE")
+     */
+    public $state;
+
+    /**
+     * @Id
+     * @ManyToOne(targetEntity="MergeCompositeToOneKeyCountry")
+     * @JoinColumn(name="country", referencedColumnName="country")
+     */
+    public $country;
+}