Log undeclared plugin only if it is not disabled

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

@@ -1,13 +1,15 @@
 <?php
 /**
- * Copyright © Magento, Inc. All rights reserved.
- * See COPYING.txt for license details.
+ * Copyright 2020 Adobe
+ * All Rights Reserved.
  */
 declare(strict_types=1);
 
 namespace Magento\Framework\Interception;
 
 use Magento\Framework\App\Filesystem\DirectoryList;
+use Magento\Framework\App\ObjectManager;
+use Magento\Framework\App\State;
 use Magento\Framework\Config\ReaderInterface;
 use Magento\Framework\Config\ScopeInterface;
 use Magento\Framework\Interception\ObjectManager\ConfigInterface;
@@ -104,6 +106,11 @@ class PluginListGenerator implements ConfigWriterInterface, ConfigLoaderInterfac
      */
     private $scopePriorityScheme;
 
+    /**
+     * @var State
+     */
+    private State $appState;
+
     /**
      * @var array
      */
@@ -119,6 +126,7 @@ class PluginListGenerator implements ConfigWriterInterface, ConfigLoaderInterfac
      * @param LoggerInterface $logger
      * @param DirectoryList $directoryList
      * @param array $scopePriorityScheme
+     * @param State|null $appState
      */
     public function __construct(
         ReaderInterface $reader,
@@ -129,7 +137,8 @@ public function __construct(
         ClassDefinitions $classDefinitions,
         LoggerInterface $logger,
         DirectoryList $directoryList,
-        array $scopePriorityScheme = ['global']
+        array $scopePriorityScheme = ['global'],
+        ?State $appState = null
     ) {
         $this->reader = $reader;
         $this->scopeConfig = $scopeConfig;
@@ -140,6 +149,7 @@ public function __construct(
         $this->logger = $logger;
         $this->directoryList = $directoryList;
         $this->scopePriorityScheme = $scopePriorityScheme;
+        $this->appState = $appState ?? ObjectManager::getInstance()->get(State::class);
     }
 
     /**
@@ -366,9 +376,12 @@ public function trimInstanceStartingBackslash(&$plugins)
     public function filterPlugins(array &$plugins)
     {
         foreach ($plugins as $name => $plugin) {
-            if (empty($plugin['instance'])) {
+            if (!isset($plugin['instance'])) {
                 unset($plugins[$name]);
-                $this->logger->info("Reference to undeclared plugin with name '{$name}'.");
+                // Log the undeclared plugin when it is not disabled or when the app is in Developer mode.
+                if ($this->appState->getMode() === State::MODE_DEVELOPER || !($plugin['disabled'] ?? false)) {
+                    $this->logger->debug("Reference to undeclared plugin with name '{$name}'.");
+                }
             }
         }
     }