Fix required field detection.

Fix required field detection to match documentation and behavior when
validating. Having `allowEmpty` in the first validation rule, makes the
field not 'required' as the field is allowed to be empty.

Fixes #3194

lib/Cake/Test/Case/View/Helper/FormHelperTest.php

@@ -107,8 +107,7 @@ class Contact extends CakeTestModel {
 		'imrequiredonupdate' => array('notEmpty' => array('rule' => 'alphaNumeric', 'on' => 'update')),
 		'imrequiredoncreate' => array('required' => array('rule' => 'alphaNumeric', 'on' => 'create')),
 		'imrequiredonboth' => array(
-			'required' => array('rule' => 'alphaNumeric', 'allowEmpty' => true),
-			'check' => array('rule' => 'alphaNumeric')
+			'required' => array('rule' => 'alphaNumeric'),
 		),
 		'string_required' => 'notEmpty',
 		'imalsorequired' => array('rule' => 'alphaNumeric', 'allowEmpty' => false),

lib/Cake/View/Helper/FormHelper.php

@@ -244,13 +244,16 @@ protected function _introspectModel($model, $key, $field = null) {
  * @return boolean true if field is required to be filled, false otherwise
  */
 	protected function _isRequiredField($validationRules) {
+		if (empty($validationRules) || count($validationRules) === 0) {
+			return false;
+		}
 		foreach ($validationRules as $rule) {
 			$rule->isUpdate($this->requestType === 'put');
-			if (!$rule->isEmptyAllowed()) {
-				return true;
+			if ($rule->isEmptyAllowed()) {
+				return false;
 			}
 		}
-		return false;
+		return true;
 	}
 
 /**