Fix #1216 and the fallback theme

.phpstan.dist.neon

@@ -77,33 +77,33 @@ parameters:
             # @todo add classes to widgets
             message: '#^Variable \$this might not be defined\.$#'
             paths:
-                - app/design/adminhtml/default/default/template/api/usernroles.phtml
-                - app/design/adminhtml/default/default/template/dashboard/searches.phtml
-                - app/design/adminhtml/default/default/template/dashboard/store/switcher.phtml
-                - app/design/adminhtml/default/default/template/empty.phtml
-                - app/design/adminhtml/default/default/template/overlay_popup.phtml
-                - app/design/adminhtml/default/default/template/popup.phtml
-                - app/design/adminhtml/default/default/template/promo/form.phtml
-                - app/design/adminhtml/default/default/template/rating/stars/detailed.phtml
-                - app/design/adminhtml/default/default/template/review/add.phtml
-                - app/design/adminhtml/default/default/template/sales/billing/agreement/form.phtml
-                - app/design/adminhtml/default/default/template/sales/items/renderer/default.phtml
-                - app/design/adminhtml/default/default/template/sales/order/shipment/create/items/renderer/configurable.phtml
-                - app/design/adminhtml/default/default/template/sales/order/totals/discount.phtml
-                - app/design/adminhtml/default/default/template/sales/order/totals/due.phtml
-                - app/design/adminhtml/default/default/template/sales/order/totals/footer.phtml
-                - app/design/adminhtml/default/default/template/sales/order/totals/grand.phtml
-                - app/design/adminhtml/default/default/template/sales/order/totals/item.phtml
-                - app/design/adminhtml/default/default/template/sales/order/totals/main.phtml
-                - app/design/adminhtml/default/default/template/sales/order/totals/paid.phtml
-                - app/design/adminhtml/default/default/template/sales/order/totals/refunded.phtml
-                - app/design/adminhtml/default/default/template/sales/order/totals/shipping.phtml
-                - app/design/adminhtml/default/default/template/sales/order/totals/subtotal.phtml
-                - app/design/adminhtml/default/default/template/sales/order/view/tracking.phtml
-                - app/design/adminhtml/default/default/template/system/info.phtml
-                - app/design/adminhtml/default/default/template/tax/class/page/edit.phtml
-                - app/design/adminhtml/default/default/template/tax/toolbar/class/save.phtml
-                - app/design/adminhtml/default/default/template/tax/toolbar/rule/save.phtml
+                - app/design/adminhtml/base/default/template/api/usernroles.phtml
+                - app/design/adminhtml/base/default/template/dashboard/searches.phtml
+                - app/design/adminhtml/base/default/template/dashboard/store/switcher.phtml
+                - app/design/adminhtml/base/default/template/empty.phtml
+                - app/design/adminhtml/base/default/template/overlay_popup.phtml
+                - app/design/adminhtml/base/default/template/popup.phtml
+                - app/design/adminhtml/base/default/template/promo/form.phtml
+                - app/design/adminhtml/base/default/template/rating/stars/detailed.phtml
+                - app/design/adminhtml/base/default/template/review/add.phtml
+                - app/design/adminhtml/base/default/template/sales/billing/agreement/form.phtml
+                - app/design/adminhtml/base/default/template/sales/items/renderer/default.phtml
+                - app/design/adminhtml/base/default/template/sales/order/shipment/create/items/renderer/configurable.phtml
+                - app/design/adminhtml/base/default/template/sales/order/totals/discount.phtml
+                - app/design/adminhtml/base/default/template/sales/order/totals/due.phtml
+                - app/design/adminhtml/base/default/template/sales/order/totals/footer.phtml
+                - app/design/adminhtml/base/default/template/sales/order/totals/grand.phtml
+                - app/design/adminhtml/base/default/template/sales/order/totals/item.phtml
+                - app/design/adminhtml/base/default/template/sales/order/totals/main.phtml
+                - app/design/adminhtml/base/default/template/sales/order/totals/paid.phtml
+                - app/design/adminhtml/base/default/template/sales/order/totals/refunded.phtml
+                - app/design/adminhtml/base/default/template/sales/order/totals/shipping.phtml
+                - app/design/adminhtml/base/default/template/sales/order/totals/subtotal.phtml
+                - app/design/adminhtml/base/default/template/sales/order/view/tracking.phtml
+                - app/design/adminhtml/base/default/template/system/info.phtml
+                - app/design/adminhtml/base/default/template/tax/class/page/edit.phtml
+                - app/design/adminhtml/base/default/template/tax/toolbar/class/save.phtml
+                - app/design/adminhtml/base/default/template/tax/toolbar/rule/save.phtml
                 - app/design/frontend/base/default/template/bundle/catalog/product/list/partof.phtml
                 - app/design/frontend/base/default/template/bundle/catalog/product/view/options/notice.phtml
                 - app/design/frontend/base/default/template/catalog/category/page.phtml

app/code/core/Mage/Adminhtml/Controller/Action.php

@@ -153,15 +153,15 @@ public function preDispatch()
     {
         // get legacy theme choice form backend config
         if (Mage::getStoreConfigFlag('admin/design/use_legacy_theme')) {
-            $theme = Mage::getConfig()->getNode('stores/admin/design/theme/default');
+            $package = Mage::getConfig()->getNode('stores/admin/design/package/name');
         } else {
-            $theme = Mage::getConfig()->getNode('stores/admin/design/theme/openmage');
+            $package = Mage::getConfig()->getNode('stores/admin/design/package/openmage');
         }
 
         Mage::getDesign()
             ->setArea($this->_currentArea)
-            ->setPackageName((string) Mage::getConfig()->getNode('stores/admin/design/package/name'))
-            ->setTheme((string) $theme);
+            ->setPackageName((string) $package)
+            ->setTheme((string) Mage::getConfig()->getNode('stores/admin/design/theme/default'));
         foreach (['layout', 'template', 'skin', 'locale'] as $type) {
             if ($value = (string) Mage::getConfig()->getNode("stores/admin/design/theme/{$type}")) {
                 Mage::getDesign()->setTheme($type, $value);

app/code/core/Mage/Adminhtml/etc/config.xml

@@ -230,10 +230,10 @@
             <design>
                 <package>
                     <name>default</name>
+                    <openmage>openmage</openmage>
                 </package>
                 <theme>
                     <default>default</default>
-                    <openmage>openmage</openmage>
                 </theme>
             </design>
         </admin>

app/code/core/Mage/Core/Model/Design/Fallback.php

@@ -88,11 +88,24 @@ public function getFallbackScheme($area, $package, $theme)
         $cacheKey = $area . '/' . $package . '/' . $theme;
 
         if (!isset($this->_cachedSchemes[$cacheKey])) {
+
+            //First we have to check if theme exists
+            $path = $area . DS . $package . DS . $theme;
+            $fallback = false;
+            if (!is_dir(Mage::getBaseDir('design') . DS . $path)) {
+                //Fallback to default
+                $theme = (string) Mage::getConfig()->getNode('stores/admin/design/theme/default');
+                $fallback = true;
+            }
             if ($this->_isInheritanceDefined($area, $package, $theme)) {
                 $scheme = $this->_getFallbackScheme($area, $package, $theme);
             } else {
                 $scheme = $this->_getLegacyFallbackScheme();
             }
+            if ($fallback) {
+                $first = array_shift($scheme);
+                $scheme = array_merge([$first], [['_package' => $package, '_theme' => $theme]], $scheme);
+            }
 
             $this->_cachedSchemes[$cacheKey] = $scheme;
         }

app/code/core/Mage/Core/Model/Layout/Update.php

@@ -433,6 +433,7 @@ public function getFileLayoutUpdatesXml($area, $package, $theme, $storeId = null
         $layoutXml = null;
         $elementClass = $this->getElementClass();
         $updatesRoot = Mage::app()->getConfig()->getNode($area . '/layout/updates');
+        $updatesRoot = $this->addFallbackThemesLayoutUpdates($updatesRoot);
         Mage::dispatchEvent('core_layout_update_updates_get_after', ['updates' => $updatesRoot]);
         $updates = $updatesRoot->asArray();
         $themeUpdates = Mage::getSingleton('core/design_config')->getNode("$area/$package/$theme/layout/updates");
@@ -473,4 +474,43 @@ public function getFileLayoutUpdatesXml($area, $package, $theme, $storeId = null
         }
         return simplexml_load_string('<layouts>' . $layoutStr . '</layouts>', $elementClass);
     }
+
+    /**
+     * Add layout files added via theme.xml to layout updates
+     * for all themes that are parents of this theme.
+     */
+    public function addFallbackThemesLayoutUpdates(Mage_Core_Model_Config_Element $updates)
+    {
+        /* @var $designPackage Mage_Core_Model_Design_Package */
+        $designPackage = Mage::getSingleton('core/design_package');
+        /* @var $fallback Mage_Core_Model_Design_Fallback */
+        $fallback = Mage::getModel('core/design_fallback');
+
+        $fallbacks = $fallback->getFallbackScheme($designPackage->getArea(), $designPackage->getPackageName(), $designPackage->getTheme('layout'));
+
+        for ($i = count($fallbacks) - 1; $i >= 0; $i--) {
+            $fallback = $fallbacks[$i];
+            if (!isset($fallback['_package'], $fallback['_theme'])) {
+                continue;
+            }
+
+            $fallbackPackage = $fallback['_package'];
+            $fallbackTheme = $fallback['_theme'];
+
+            $themeUpdateGroups = Mage::getSingleton('core/design_config')->getNode("{$designPackage->getArea()}/$fallbackPackage/$fallbackTheme/layout/updates");
+
+            if (!$themeUpdateGroups) {
+                continue;
+            }
+
+            foreach ($themeUpdateGroups as $themeUpdateGroup) {
+                foreach ($themeUpdateGroup->asArray() as $key => $themeUpdate) {
+                    $updateNode = $updates->addChild($key);
+                    $updateNode->addChild('file', $themeUpdate['file']);
+                }
+            }
+        }
+
+        return $updates;
+    }
 }

app/design/adminhtml/base/default/etc/theme.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0"?>
+<!--
+/**
+ * OpenMage
+ *
+ * This source file is subject to the Academic Free License (AFL 3.0)
+ * that is bundled with this package in the file LICENSE_AFL.txt.
+ * It is also available at https://opensource.org/license/afl-3-0-php
+ *
+ * @category    design
+ * @package     default_default
+ * @copyright   Copyright (c) 2006-2020 Magento, Inc. (https://www.magento.com)
+ * @copyright   Copyright (c) 2022 The OpenMage Contributors (https://www.openmage.org)
+ * @license     https://opensource.org/licenses/afl-3.0.php  Academic Free License (AFL 3.0)
+ */
+-->
+<theme>
+    <parent />
+</theme>