MDL-74967 core: deprecate groupmember hack from USER object

lib/modinfolib.php

@@ -287,11 +287,6 @@ class course_modinfo {
      */
     private function get_groups_all() {
         if (is_null($this->groups)) {
-            // NOTE: Performance could be improved here. The system caches user groups
-            // in $USER->groupmember[$courseid] => array of groupid=>groupid. Unfortunately this
-            // structure does not include grouping information. It probably could be changed to
-            // do so, without a significant performance hit on login, thus saving this one query
-            // each request.
             $this->groups = groups_get_user_groups($this->course->id, $this->userid);
         }
         return $this->groups;

lib/moodlelib.php

@@ -4883,23 +4883,6 @@ function get_complete_user_data($field, $value, $mnethostid = null, $throwexcept
         }
     }
 
-    $sql = "SELECT g.id, g.courseid
-              FROM {groups} g, {groups_members} gm
-             WHERE gm.groupid=g.id AND gm.userid=?";
-
-    // This is a special hack to speedup calendar display.
-    $user->groupmember = array();
-    if (!isguestuser($user)) {
-        if ($groups = $DB->get_records_sql($sql, array($user->id))) {
-            foreach ($groups as $group) {
-                if (!array_key_exists($group->courseid, $user->groupmember)) {
-                    $user->groupmember[$group->courseid] = array();
-                }
-                $user->groupmember[$group->courseid][$group->id] = $group->id;
-            }
-        }
-    }
-
     // Add cohort theme.
     if (!empty($CFG->allowcohortthemes)) {
         require_once($CFG->dirroot . '/cohort/lib.php');

lib/upgrade.txt

@@ -3,6 +3,8 @@ information provided here is intended especially for developers.
 
 === 4.1 ===
 
+* The $USER->groupmember hack that fills the user object with the groups that the user belongs to has been removed.
+  Please use the Groups API function groups_get_user_groups() to fetch the cached list of groups the user is a member of.
 * The method ensure_adhoc_task_qos() in lib/classes/task/manager.php  has been deprecated, please use get_next_adhoc_task()
   instead.
 * New setting $CFG->enrolments_sync_interval controls the minimum time in seconds between re-synchronization of enrollment via enrol_check_plugins.