[5.4][6.0] Fix installation error on Windows

installation/src/Model/CleanupModel.php

@@ -10,6 +10,7 @@
 
 namespace Joomla\CMS\Installation\Model;
 
+use Joomla\Filesystem\Exception\FilesystemException;
 use Joomla\Filesystem\File;
 use Joomla\Filesystem\Folder;
 
@@ -33,15 +34,48 @@ class CleanupModel extends BaseInstallationModel
      */
     public function deleteInstallationFolder()
     {
-        $return = Folder::delete(JPATH_INSTALLATION) && (!file_exists(JPATH_ROOT . '/joomla.xml') || File::delete(JPATH_ROOT . '/joomla.xml'));
+        // First, we try to delete the installation folder
+        try {
+            Folder::delete(JPATH_INSTALLATION);
+        } catch (FilesystemException $e) {
+            /**
+             * Windows quirk: The installation folder may fail to delete because
+             * index.php, though already deleted, remains locked by PHP until
+             * the request ends. If no subfolders and only that file is present,
+             * we can assume the deletion effectively successful and continue cleanup.
+             */
+            if (PHP_OS_FAMILY === 'Windows') {
+                $files   = Folder::files(JPATH_INSTALLATION);
+                $folders = Folder::folders(JPATH_INSTALLATION);
+
+                if (\count($folders) > 0 || \count($files) > 1) {
+                    return false;
+                }
+            } else {
+                return false;
+            }
+        }
+
+        // Remove file joomla.xml in root folder if it exists
+        if (file_exists(JPATH_ROOT . '/joomla.xml')) {
+            try {
+                File::delete(JPATH_ROOT . '/joomla.xml');
+            } catch (FilesystemException $e) {
+                return false;
+            }
+        }
 
         // Rename the robots.txt.dist file if robots.txt doesn't exist
-        if ($return && !file_exists(JPATH_ROOT . '/robots.txt') && file_exists(JPATH_ROOT . '/robots.txt.dist')) {
-            $return = File::move(JPATH_ROOT . '/robots.txt.dist', JPATH_ROOT . '/robots.txt');
+        if (!file_exists(JPATH_ROOT . '/robots.txt') && file_exists(JPATH_ROOT . '/robots.txt.dist')) {
+            try {
+                File::move(JPATH_ROOT . '/robots.txt.dist', JPATH_ROOT . '/robots.txt');
+            } catch (FilesystemException $e) {
+                return false;
+            }
         }
 
         clearstatcache(true, JPATH_INSTALLATION . '/index.php');
 
-        return $return;
+        return true;
     }
 }