diff --git a/src/Symfony/Component/Form/ButtonBuilder.php b/src/Symfony/Component/Form/ButtonBuilder.php
index ce30b0ab26..2f0cbee06d 100644
--- a/src/Symfony/Component/Form/ButtonBuilder.php
+++ b/src/Symfony/Component/Form/ButtonBuilder.php
@@ -710,7 +710,7 @@ class ButtonBuilder implements \IteratorAggregate, FormBuilderInterface
      */
     public function hasAttribute($name)
     {
-        return isset($this->attributes[$name]);
+        return array_key_exists($name, $this->attributes);
     }
 
     /**
@@ -723,7 +723,7 @@ class ButtonBuilder implements \IteratorAggregate, FormBuilderInterface
      */
     public function getAttribute($name, $default = null)
     {
-        return isset($this->attributes[$name]) ? $this->attributes[$name] : $default;
+        return array_key_exists($name, $this->attributes) ? $this->attributes[$name] : $default;
     }
 
     /**
@@ -785,7 +785,7 @@ class ButtonBuilder implements \IteratorAggregate, FormBuilderInterface
      */
     public function hasOption($name)
     {
-        return isset($this->options[$name]);
+        return array_key_exists($name, $this->options);
     }
 
     /**
@@ -798,7 +798,7 @@ class ButtonBuilder implements \IteratorAggregate, FormBuilderInterface
      */
     public function getOption($name, $default = null)
     {
-        return isset($this->options[$name]) ? $this->options[$name] : $default;
+        return array_key_exists($name, $this->options) ? $this->options[$name] : $default;
     }
 
     /**
diff --git a/src/Symfony/Component/Form/FormConfigBuilder.php b/src/Symfony/Component/Form/FormConfigBuilder.php
index 7d297ed33d..c52b4169e8 100644
--- a/src/Symfony/Component/Form/FormConfigBuilder.php
+++ b/src/Symfony/Component/Form/FormConfigBuilder.php
@@ -392,7 +392,7 @@ class FormConfigBuilder implements FormConfigBuilderInterface
      */
     public function hasAttribute($name)
     {
-        return isset($this->attributes[$name]);
+        return array_key_exists($name, $this->attributes);
     }
 
     /**
@@ -400,7 +400,7 @@ class FormConfigBuilder implements FormConfigBuilderInterface
      */
     public function getAttribute($name, $default = null)
     {
-        return isset($this->attributes[$name]) ? $this->attributes[$name] : $default;
+        return array_key_exists($name, $this->attributes) ? $this->attributes[$name] : $default;
     }
 
     /**
@@ -448,7 +448,7 @@ class FormConfigBuilder implements FormConfigBuilderInterface
      */
     public function hasOption($name)
     {
-        return isset($this->options[$name]);
+        return array_key_exists($name, $this->options);
     }
 
     /**
@@ -456,7 +456,7 @@ class FormConfigBuilder implements FormConfigBuilderInterface
      */
     public function getOption($name, $default = null)
     {
-        return isset($this->options[$name]) ? $this->options[$name] : $default;
+        return array_key_exists($name, $this->options) ? $this->options[$name] : $default;
     }
 
     /**