Previously the role assignment url was used when a role was selected, but
this page doesn't enrol users into the course (its the old 1.9 way
before we had the enrollments table).
Preferences pages cancel and continue buttons should lead back to preferences page.
Site pages should have consistent headers and breadcrumbs.
Hide the "Preferences" node in the navigation.
Part of MDL-45774
List of changes:
* New OOP API using PHP namespace \core\session\.
* All handlers now update the sessions table consistently.
* Experimental DB session support in Oracle.
* Full support for session file handler (filesystem locking required).
* New option for alternative session directory.
* Official memcached session handler support.
* Workaround for memcached version with non-functional gc.
* Improved security - forced session id regeneration.
* Improved compatibility with recent PHP releases.
* Fixed borked CSS during install in debug mode.
* Switched to file based sessions in new installs.
* DB session setting disappears if DB does not support sessions.
* DB session setting disappears if session handler specified in config.php.
* Fast purging of sessions used in request only.
* No legacy distinction - file, database and memcached support the same functionality.
* Session handler name included in performance info.
* Fixed user_loggedin and user_loggedout event triggering.
* Other minor bugfixing and improvements.
* Fixed database session segfault if MUC disposed before $DB.
Limitations:
* Session access time is now updated right after session start.
* Support for $CFG->sessionlockloggedinonly was removed.
* First request does not update userid in sessions table.
* The timeouts may break badly if server hosting forces PHP.ini session settings.
* The session GC is a lot slower, we do not rely on external session timeouts.
* There cannot be any hooks triggered at the session write time.
* File and memcached handlers do not support session lock acquire timeouts.
* Some low level PHP session functions can not be used directly in Moodle code.
Capability checks are performed at the top of the page and do not need
to be completed again.
Search is an expected feature for users and it was confusion to only
appear after 3 pages. This has been changed to enable search when
there are more records than are visible on the screen. If users
are unable to use browser search, they will be able to use Moodle's
search.
