diff --git a/src/Symfony/Component/Routing/Generator/UrlGenerator.php b/src/Symfony/Component/Routing/Generator/UrlGenerator.php
index 307b5a588f..18edd160dd 100644
--- a/src/Symfony/Component/Routing/Generator/UrlGenerator.php
+++ b/src/Symfony/Component/Routing/Generator/UrlGenerator.php
@@ -23,7 +23,6 @@ use Symfony\Component\HttpKernel\Log\LoggerInterface;
  * UrlGenerator generates a URL based on a set of routes.
  *
  * @author Fabien Potencier <fabien@symfony.com>
- * @author Tobias Schultze <http://tobion.de>
  *
  * @api
  */
@@ -133,10 +132,13 @@ class UrlGenerator implements UrlGeneratorInterface, ConfigurableRequirementsInt
     protected function doGenerate($variables, $defaults, $requirements, $tokens, $parameters, $name, $absolute)
     {
         $variables = array_flip($variables);
-        $mergedParams = array_replace($this->context->getParameters(), $defaults, $parameters);
+
+        $originParameters = $parameters;
+        $parameters = array_replace($this->context->getParameters(), $parameters);
+        $tparams = array_replace($defaults, $parameters);
 
         // all params must be given
-        if ($diff = array_diff_key($variables, $mergedParams)) {
+        if ($diff = array_diff_key($variables, $tparams)) {
             throw new MissingMandatoryParametersException(sprintf('The "%s" route has some missing mandatory parameters ("%s").', $name, implode('", "', array_keys($diff))));
         }
 
@@ -144,26 +146,30 @@ class UrlGenerator implements UrlGeneratorInterface, ConfigurableRequirementsInt
         $optional = true;
         foreach ($tokens as $token) {
             if ('variable' === $token[0]) {
-                if (!$optional || !array_key_exists($token[3], $defaults) || (string) $mergedParams[$token[3]] !== (string) $defaults[$token[3]]) {
-                    // check requirement
-                    if (!preg_match('#^'.$token[2].'$#', $mergedParams[$token[3]])) {
-                        $message = sprintf('Parameter "%s" for route "%s" must match "%s" ("%s" given).', $token[3], $name, $token[2], $mergedParams[$token[3]]);
-                        if ($this->strictRequirements) {
-                            throw new InvalidParameterException($message);
-                        }
+                if (false === $optional || !array_key_exists($token[3], $defaults) || (isset($parameters[$token[3]]) && (string) $parameters[$token[3]] != (string) $defaults[$token[3]])) {
+                    if (!$isEmpty = in_array($tparams[$token[3]], array(null, '', false), true)) {
+                        // check requirement
+                        if ($tparams[$token[3]] && !preg_match('#^'.$token[2].'$#', $tparams[$token[3]])) {
+                            $message = sprintf('Parameter "%s" for route "%s" must match "%s" ("%s" given).', $token[3], $name, $token[2], $tparams[$token[3]]);
+                            if ($this->strictRequirements) {
+                                throw new InvalidParameterException($message);
+                            }
 
-                        if ($this->logger) {
-                            $this->logger->err($message);
-                        }
+                            if ($this->logger) {
+                                $this->logger->err($message);
+                            }
 
-                        return null;
+                            return null;
+                        }
+                    }
+
+                    if (!$isEmpty || !$optional) {
+                        $url = $token[1].$tparams[$token[3]].$url;
                     }
 
-                    $url = $token[1].$mergedParams[$token[3]].$url;
                     $optional = false;
                 }
-            } else {
-                // static text
+            } elseif ('text' === $token[0]) {
                 $url = $token[1].$url;
                 $optional = false;
             }
@@ -187,7 +193,7 @@ class UrlGenerator implements UrlGeneratorInterface, ConfigurableRequirementsInt
         }
 
         // add a query string if needed
-        $extra = array_diff_key($parameters, $variables);
+        $extra = array_diff_key($originParameters, $variables, $defaults);
         if ($extra && $query = http_build_query($extra, '', '&')) {
             $url .= '?'.$query;
         }
diff --git a/src/Symfony/Component/Routing/Tests/Generator/UrlGeneratorTest.php b/src/Symfony/Component/Routing/Tests/Generator/UrlGeneratorTest.php
index 236015f976..f001067a53 100644
--- a/src/Symfony/Component/Routing/Tests/Generator/UrlGeneratorTest.php
+++ b/src/Symfony/Component/Routing/Tests/Generator/UrlGeneratorTest.php
@@ -74,15 +74,12 @@ class UrlGeneratorTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals('/app.php/testing', $url);
     }
 
-    /**
-     * @expectedException Symfony\Component\Routing\Exception\InvalidParameterException
-     */
     public function testRelativeUrlWithNullParameterButNotOptional()
     {
         $routes = $this->getRoutes('test', new Route('/testing/{foo}/bar', array('foo' => null)));
-        // This must raise an exception because the default requirement for "foo" is "[^/]+" which is not met with these params.
-        // Generating path "/testing//bar" would be wrong as matching this route would fail.
-        $this->getGenerator($routes)->generate('test', array(), false);
+        $url = $this->getGenerator($routes)->generate('test', array(), false);
+
+        $this->assertEquals('/app.php/testing//bar', $url);
     }
 
     public function testRelativeUrlWithOptionalZeroParameter()
@@ -93,13 +90,6 @@ class UrlGeneratorTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals('/app.php/testing/0', $url);
     }
 
-    public function testNotPassedOptionalParameterInBetween()
-    {
-        $routes = $this->getRoutes('test', new Route('/{slug}/{page}', array('slug' => 'index', 'page' => 0)));
-        $this->assertSame('/app.php/index/1', $this->getGenerator($routes)->generate('test', array('page' => 1)));
-        $this->assertSame('/app.php/', $this->getGenerator($routes)->generate('test'));
-    }
-
     public function testRelativeUrlWithExtraParameters()
     {
         $routes = $this->getRoutes('test', new Route('/testing'));
@@ -175,15 +165,6 @@ class UrlGeneratorTest extends \PHPUnit_Framework_TestCase
         $this->getGenerator($routes)->generate('test', array('foo' => 'bar'), true);
     }
 
-    /**
-     * @expectedException Symfony\Component\Routing\Exception\InvalidParameterException
-     */
-    public function testGenerateForRouteWithInvalidParameter()
-    {
-        $routes = $this->getRoutes('test', new Route('/testing/{foo}', array(), array('foo' => '1|2')));
-        $this->getGenerator($routes)->generate('test', array('foo' => '0'), true);
-    }
-
     public function testGenerateForRouteWithInvalidOptionalParameterNonStrict()
     {
         $routes = $this->getRoutes('test', new Route('/testing/{foo}', array('foo' => '1'), array('foo' => 'd+')));
@@ -215,15 +196,6 @@ class UrlGeneratorTest extends \PHPUnit_Framework_TestCase
         $routes = $this->getRoutes('test', new Route('/testing/{foo}', array(), array('foo' => 'd+')));
         $this->getGenerator($routes)->generate('test', array('foo' => 'bar'), true);
     }
-    
-    /**
-     * @expectedException Symfony\Component\Routing\Exception\InvalidParameterException
-     */
-    public function testRequiredParamAndEmptyPassed()
-    {
-        $routes = $this->getRoutes('test', new Route('/{slug}', array(), array('slug' => '.+')));
-        $this->getGenerator($routes)->generate('test', array('slug' => ''));
-    }
 
     public function testSchemeRequirementDoesNothingIfSameCurrentScheme()
     {
@@ -257,15 +229,6 @@ class UrlGeneratorTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals('/app.php/foo', $this->getGenerator($routes)->generate('test', array('default' => 'foo')));
     }
 
-    public function testQueryParamSameAsDefault()
-    {
-        $routes = $this->getRoutes('test', new Route('/test', array('default' => 'value')));
-
-        $this->assertSame('/app.php/test?default=foo', $this->getGenerator($routes)->generate('test', array('default' => 'foo')));
-        $this->assertSame('/app.php/test?default=value', $this->getGenerator($routes)->generate('test', array('default' => 'value')));
-        $this->assertSame('/app.php/test', $this->getGenerator($routes)->generate('test'));
-    }
-
     public function testUrlEncoding()
     {
         // This tests the encoding of reserved characters that are used for delimiting of URI components (defined in RFC 3986)