[Form] Changed isset() to array_key_exists() to be consistent with ParameterBag

Author: webmozart

ButtonBuilder.php

@@ -710,7 +710,7 @@ public function getAttributes()
      */
     public function hasAttribute($name)
     {
-        return isset($this->attributes[$name]);
+        return array_key_exists($name, $this->attributes);
     }
 
     /**
@@ -723,7 +723,7 @@ public function hasAttribute($name)
      */
     public function getAttribute($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 @@ public function getOptions()
      */
     public function hasOption($name)
     {
-        return isset($this->options[$name]);
+        return array_key_exists($name, $this->options);
     }
 
     /**
@@ -798,7 +798,7 @@ public function hasOption($name)
      */
     public function getOption($name, $default = null)
     {
-        return isset($this->options[$name]) ? $this->options[$name] : $default;
+        return array_key_exists($name, $this->options) ? $this->options[$name] : $default;
     }
 
     /**

FormConfigBuilder.php

@@ -392,15 +392,15 @@ public function getAttributes()
      */
     public function hasAttribute($name)
     {
-        return isset($this->attributes[$name]);
+        return array_key_exists($name, $this->attributes);
     }
 
     /**
      * {@inheritdoc}
      */
     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;
     }
 
     /**
@@ -448,15 +448,15 @@ public function getOptions()
      */
     public function hasOption($name)
     {
-        return isset($this->options[$name]);
+        return array_key_exists($name, $this->options);
     }
 
     /**
      * {@inheritdoc}
      */
     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;
     }
 
     /**