Magento Framework - Performance improvements

 - cache parents list in Code/Reader/ClassReader.php
 - replace array_key_exists() by isset() (2nd a bit faster, but that will change in PHP 7.4)

Author: andrey-legayev

lib/internal/Magento/Framework/Code/Reader/ClassReader.php

@@ -7,6 +7,8 @@
 
 class ClassReader implements ClassReaderInterface
 {
+    private $parentsCache = [];
+
     /**
      * Read class constructor signature
      *
@@ -54,6 +56,10 @@ public function getConstructor($className)
      */
     public function getParents($className)
     {
+        if (isset($this->parentsCache[$className])) {
+            return $this->parentsCache[$className];
+        }
+
         $parentClass = get_parent_class($className);
         if ($parentClass) {
             $result = [];
@@ -75,6 +81,9 @@ public function getParents($className)
                 $result = [];
             }
         }
+
+        $this->parentsCache[$className] = $result;
+
         return $result;
     }
 }

lib/internal/Magento/Framework/Interception/PluginList/PluginList.php

@@ -138,7 +138,7 @@ public function __construct(
     protected function _inheritPlugins($type)
     {
         $type = ltrim($type, '\\');
-        if (!array_key_exists($type, $this->_inherited)) {
+        if (!isset($this->_inherited[$type])) {
             $realType = $this->_omConfig->getOriginalInstanceType($type);
 
             if ($realType !== $type) {

lib/internal/Magento/Framework/ObjectManager/Definition/Runtime.php

@@ -45,7 +45,7 @@ public function __construct(\Magento\Framework\Code\Reader\ClassReaderInterface
      */
     public function getParameters($className)
     {
-        if (!array_key_exists($className, $this->_definitions)) {
+        if (!isset($this->_definitions[$className])) {
             $this->_definitions[$className] = $this->_reader->getConstructor($className);
         }
         return $this->_definitions[$className];