Fix bug where subfolders of special folders could have been duplicated on folder list

CHANGELOG

@@ -1,6 +1,8 @@
 CHANGELOG Roundcube Webmail
 ===========================
 
+- Fix bug where subfolders of special folders could have been duplicated on folder list
+
 RELEASE 1.4.6
 -------------
 - Installer: Fix regression in SMTP test section (#7417)

program/lib/Roundcube/rcube_imap.php

@@ -4390,10 +4390,17 @@ class rcube_imap extends rcube_storage
      */
     protected function sort_folder_specials($folder, &$list, &$specials, &$out)
     {
-        foreach ($list as $key => $name) {
+        $count = count($list);
+
+        for ($i = 0; $i < $count; $i++) {
+            $name = $list[$i];
+            if ($name === null) {
+                continue;
+            }
+
             if ($folder === null || strpos($name, $folder.$this->delimiter) === 0) {
                 $out[] = $name;
-                unset($list[$key]);
+                $list[$i] = null;
 
                 if (!empty($specials) && ($found = array_search($name, $specials)) !== false) {
                     unset($specials[$found]);
@@ -4401,8 +4408,6 @@ class rcube_imap extends rcube_storage
                 }
             }
         }
-
-        reset($list);
     }
 
     /**

tests/Framework/Imap.php

@@ -17,4 +17,65 @@ class Framework_Imap extends PHPUnit_Framework_TestCase
 
         $this->assertInstanceOf('rcube_imap', $object, "Class constructor");
     }
+
+    /**
+     * Folder sorting
+     */
+    function test_sort_folder_list()
+    {
+        $_SESSION['imap_delimiter'] = '.';
+        $_SESSION['imap_namespace'] = [
+            'personal' => null,
+            'other' => [['Other Users.', '.']],
+            'shared' => [['Shared.', '.']],
+        ];
+
+        foreach (array('drafts', 'sent', 'junk', 'trash') as $mbox) {
+            rcube::get_instance()->config->set("$mbox_mbox", ucfirst($mbox));
+        }
+
+        $object = new rcube_imap;
+
+        $result = $object->sort_folder_list([]);
+        $this->assertSame([], $result);
+
+        $result = $object->sort_folder_list(['B', 'A']);
+        $this->assertSame(['A', 'B'], $result);
+
+        $folders = [
+            'Trash',
+            'Sent',
+            'ABC',
+            'Drafts',
+            'INBOX.Trash',
+            'INBOX.Junk',
+            'INBOX.Sent',
+            'INBOX.Drafts',
+            'Shared.Test1',
+            'Other Users.Test2',
+            'Junk',
+            'INBOX',
+            'DEF',
+        ];
+
+        $expected = [
+            'INBOX',
+            'INBOX.Drafts',
+            'INBOX.Junk',
+            'INBOX.Sent',
+            'INBOX.Trash',
+            'Drafts',
+            'Sent',
+            'Junk',
+            'Trash',
+            'ABC',
+            'DEF',
+            'Other Users.Test2',
+            'Shared.Test1',
+        ];
+
+        $result = $object->sort_folder_list($folders);
+
+        $this->assertSame($expected, $result);
+    }
 }