MAGETWO-61786: Implementation

Author: Bohdan Korablov

app/code/Magento/Config/Model/Config/Structure/AbstractElement.php

@@ -218,7 +218,9 @@ public function getPath($fieldPrefix = '')
      * Get instance of ElementVisibilityInterface.
      *
      * @return ElementVisibilityInterface
-     * @deprecated
+     * @deprecated Added to not break backward compatibility of the constructor signature
+     *             by injecting the new dependency directly.
+     *             The method can be removed in a future major release, when constructor signature can be changed.
      */
     public function getElementVisibility()
     {

app/code/Magento/Config/Model/Config/Structure/ConcealInProductionConfigList.php

@@ -8,12 +8,26 @@
 use Magento\Framework\App\State;
 
 /**
- * Contains list of elements paths which should be hidden or disabled on Configuration page in Production mode.
+ * Defines status of visibility of form elements on Store > Settings > Configuration page
+ * in Admin Panel in Production mode.
  */
 class ConcealInProductionConfigList implements ElementVisibilityInterface
 {
     /**
-     * The list of paths of form elements in the structure.
+     * The list of form element paths with concrete visibility status.
+     *
+     * E.g.
+     *
+     * ```php
+     * [
+     *      'general/locale/code' => ElementVisibilityInterface::DISABLED,
+     *      'general/country' => ElementVisibilityInterface::HIDDEN,
+     * ];
+     * ```
+     *
+     * It means that:
+     *  - field Locale (in group Locale Options in section General) will be disabled
+     *  - group Country Options (in section General) will be hidden
      *
      * @var array
      */
@@ -28,7 +42,7 @@ class ConcealInProductionConfigList implements ElementVisibilityInterface
 
     /**
      * @param State $state The object that has information about the state of the system
-     * @param array $configs The list of paths of form elements in the structure
+     * @param array $configs The list of form element paths with concrete visibility status.
      */
     public function __construct(State $state, array $configs = [])
     {
@@ -73,7 +87,7 @@ public function isDisabled($path)
     /**
      * Returns normalized path.
      *
-     * @param string $path The path will be normalized
+     * @param string $path The path to be normalized
      * @return string The normalized path
      */
     private function normalizePath($path)

app/code/Magento/Config/Model/Config/Structure/ElementVisibilityComposite.php

@@ -9,7 +9,7 @@
 
 /**
  * Contains list of classes which implement ElementVisibilityInterface for
- * checking of visibility of form elements on Configuration page.
+ * checking of visibility of form elements on Store > Settings > Configuration page in Admin Panel.
  */
 class ElementVisibilityComposite implements ElementVisibilityInterface
 {

app/code/Magento/Config/Model/Config/Structure/ElementVisibilityInterface.php

@@ -6,7 +6,8 @@
 namespace Magento\Config\Model\Config\Structure;
 
 /**
- * Checks visibility of form elements on Configuration page by their paths in the structure.
+ * Checks visibility status of form elements on Store > Settings > Configuration page in Admin Panel
+ * by their paths in the structure.
  */
 interface ElementVisibilityInterface
 {