Merge branch 'master' into psr2

* master: (34 commits)
  fix color for noninstalled extensions
  show disabled extensions in gray
  warn about inaccessible repo api
  bugfix: access check was never cached
  First go on a CLI component for the extension manager
  use strict type comparison
  translation update
  translation update
  fix #dokuwiki__sitetools current item not in highlight due to Greebo change
  authplain: Add tests for group retrieval
  authplain: Add a simple method for retrieving user groups
  translation update
  Negative string offsets are allowed in PHP 7.1+ only
  improve memory check output
  fix and test php_to_byte() related to #2756 #2556
  translation update
  translation update
  translation update
  translation update
  translation update
  ...

1 files changed, 24 insertions, 0 deletions

diff --git a/lib/plugins/authplain/auth.php b/lib/plugins/authplain/auth.php
index 374e7179c..d95c86de2 100644
--- a/lib/plugins/authplain/auth.php
+++ b/lib/plugins/authplain/auth.php
@@ -46,6 +46,7 @@ class auth_plugin_authplain extends DokuWiki_Auth_Plugin
             }
             $this->cando['getUsers']     = true;
             $this->cando['getUserCount'] = true;
+            $this->cando['getGroups']    = true;
         }
 
         $this->pregsplit_safe = version_compare(PCRE_VERSION, '6.7', '>=');
@@ -319,6 +320,29 @@ class auth_plugin_authplain extends DokuWiki_Auth_Plugin
     }
 
     /**
+     * Retrieves groups.
+     * Loads complete user data into memory before searching for groups.
+     *
+     * @param   int   $start index of first group to be returned
+     * @param   int   $limit max number of groups to be returned
+     * @return  array
+     */
+    public function retrieveGroups($start = 0, $limit = 0)
+    {
+        $groups = [];
+
+        if ($this->users === null) $this->_loadUserData();
+        foreach($this->users as $user => $info) {
+            $groups = array_merge($groups, array_diff($info['grps'], $groups));
+        }
+
+        if($limit > 0) {
+            return array_splice($groups, $start, $limit);
+        }
+        return array_splice($groups, $start);
+    }
+
+    /**
      * Only valid pageid's (no namespaces) for usernames
      *
      * @param string $user