DDC-1211 - Fix bug with empty numeric literal

lib/Doctrine/ORM/Query/Expr/Base.php

@@ -55,7 +55,7 @@ abstract class Base
 
     public function add($arg)
     {
-        if ( ! empty($arg) || ($arg instanceof self && $arg->count() > 0)) {
+        if ( $arg !== null || ($arg instanceof self && $arg->count() > 0)) {
             // If we decide to keep Expr\Base instances, we can use this check
             if ( ! is_string($arg)) {
                 $class = get_class($arg);

tests/Doctrine/Tests/ORM/QueryBuilderTest.php

@@ -681,4 +681,32 @@ class QueryBuilderTest extends \Doctrine\Tests\OrmTestCase
         
         $this->assertEquals('SELECT u FROM Doctrine\Tests\Models\CMS\CmsUser u INNER JOIN u.groups g', $qb->getDQL());
     }
+    
+    /**
+     * @group DDC-1211
+     */
+    public function testEmptyStringLiteral()
+    {
+        $expr = $this->_em->getExpressionBuilder();
+        $qb = $this->_em->createQueryBuilder()
+            ->select('u')
+            ->from('Doctrine\Tests\Models\CMS\CmsUser', 'u')
+            ->where($expr->eq('u.username', $expr->literal("")));
+        
+        $this->assertEquals("SELECT u FROM Doctrine\Tests\Models\CMS\CmsUser u WHERE u.username = ''", $qb->getDQL());
+    }
+    
+    /**
+     * @group DDC-1211
+     */
+    public function testEmptyNumericLiteral()
+    {
+        $expr = $this->_em->getExpressionBuilder();
+        $qb = $this->_em->createQueryBuilder()
+            ->select('u')
+            ->from('Doctrine\Tests\Models\CMS\CmsUser', 'u')
+            ->where($expr->eq('u.username', $expr->literal(0)));
+        
+        $this->assertEquals('SELECT u FROM Doctrine\Tests\Models\CMS\CmsUser u WHERE u.username = 0', $qb->getDQL());
+    }
 }