MDL-21782 reworked enrolment framework, the core infrastructure is in place, the basic plugins are all implemented; see the tracker issue for list of unfinished bits, expect more changes and improvements during the next week

AMOS START
    MOV [sendcoursewelcomemessage,core_admin],[sendcoursewelcomemessage,enrol_self]
    MOV [configsendcoursewelcomemessage,core_admin],[sendcoursewelcomemessage_desc,enrol_self]
    MOV [enrolstartdate,core],[enrolstartdate,enrol_self]
    MOV [enrolenddate,core],[enrolenddate,enrol_self]
    CPY [welcometocourse,core],[welcometocourse,enrol_self]
    CPY [welcometocoursetext,core],[welcometocoursetext,enrol_self]
    MOV [notenrollable,core],[notenrollable,core_enrol]
    MOV [enrolenddaterror,core],[enrolenddaterror,enrol_self]
    MOV [enrolmentkeyhint,core],[passwordinvalidhint,enrol_self]
    MOV [coursemanager,core_admin],[coursecontact,core_admin]
    MOV [configcoursemanager,core_admin],[coursecontact_desc,core_admin]
    MOV [enrolledincourserole,core],[enrolledincourserole,enrol_manual]
    MOV [enrolme,core],[enrolme,core_enrol]
    MOV [unenrol,core],[unenrol,core_enrol]
    MOV [unenrolme,core],[unenrolme,core_enrol]
    MOV [enrolmentnew,core],[enrolmentnew,core_enrol]
    MOV [enrolmentnewuser,core],[enrolmentnewuser,core_enrol]
    MOV [enrolments,core],[enrolments,core_enrol]
    MOV [enrolperiod,core],[enrolperiod,core_enrol]
    MOV [unenrolroleusers,core],[unenrolroleusers,core_enrol]
AMOS END

lib/sessionlib.php

@@ -74,7 +74,7 @@ interface moodle_session {
      * @return void
      */
     public function write_close();
-    
+
     /**
      * Check for existing session with id $sid
      * @param unknown_type $sid
@@ -159,7 +159,7 @@ abstract class session_stub implements moodle_session {
         } catch (Exception $ignored) {
             // probably install/upgrade - ignore this problem
         }
-        
+
         if (NO_MOODLE_COOKIES) {
             return;
         }
@@ -372,7 +372,7 @@ class legacy_file_session extends session_stub {
         $sessionfile = clean_param("$CFG->dataroot/sessions/sess_$sid", PARAM_FILE);
         return file_exists($sessionfile);
     }
-    
+
 
 }
 
@@ -401,20 +401,20 @@ class database_session extends session_stub {
             }
         }
     }
-    
+
     public function session_exists($sid){
         global $CFG;
         try {
             $sql = "SELECT * FROM {sessions} WHERE timemodified < ? AND sid=? AND state=?";
             $params = array(time() + $CFG->sessiontimeout, $sid, 0);
-            
+
             return $this->database->record_exists_sql($sql, $params);
         } catch (dml_exception $ex) {
             error_log('Error checking existance of database session');
             return false;
         }
     }
-    
+
     protected function init_session_storage() {
         global $CFG;
 
@@ -878,7 +878,7 @@ function session_set_user($user) {
     unset($_SESSION['USER']->description); // conserve memory
     if (!isset($_SESSION['USER']->access)) {
         // check enrolments and load caps only once
-        check_enrolment_plugins($_SESSION['USER']);
+        enrol_check_plugins($_SESSION['USER']);
         load_all_capabilities();
     }
     sesskey(); // init session key