[DDC-1087] Add missing resolution to IS NULL in EntityRepository when passing a null value as a criteria.

lib/Doctrine/ORM/Persisters/BasicEntityPersister.php

@@ -1206,7 +1206,7 @@ class BasicEntityPersister
             } else {
                 throw ORMException::unrecognizedField($field);
             }
-            $conditionSql .= (is_array($value)) ? ' IN (?)' : ' = ?';
+            $conditionSql .= (is_array($value)) ? ' IN (?)' : (($value === null) ? ' IS NULL' : ' = ?');
         }
         return $conditionSql;
     }
@@ -1291,6 +1291,10 @@ class BasicEntityPersister
         $params = $types = array();
 
         foreach ($criteria AS $field => $value) {
+            if ($value === null) {
+                continue; // skip null values.
+            }
+
             $type = null;
             if (isset($this->_class->fieldMappings[$field])) {
                 $type = Type::getType($this->_class->fieldMappings[$field]['type'])->getBindingType();

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

@@ -307,5 +307,18 @@ class EntityRepositoryTest extends \Doctrine\Tests\OrmFunctionalTestCase
 
         $repos->createNamedQuery('invalidNamedQuery');
     }
+
+    /**
+     * @group DDC-1087
+     */
+    public function testIsNullCriteria()
+    {
+        $repos = $this->_em->getRepository('Doctrine\Tests\Models\CMS\CmsUser');
+        $users = $repos->findBy(array('status' => null, 'username' => 'romanb'));
+
+        $params = $this->_sqlLoggerStack->queries[$this->_sqlLoggerStack->currentQuery]['params'];
+        $this->assertEquals(1, count($params), "Should only execute with one parameter.");
+        $this->assertEquals(array('romanb'), $params);
+    }
 }