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.
This combines the following changes:
* Event for group member added
* Event for group member removed
* Event for group created
* Event for grouping created
* Event for group updated
* Event for grouping updated
* Event for group deleted
* Event for grouping deleted
* Adding tests for deleting functions
* Bulk remove of members uses low-level API
The reason for this is that a bulk event has no value from a logging
perspective as it is not granular. So now, the API is a bit slower,
but the information the events contain makes sense, beside this is
not (and should not be) used very often.
The reason why the events_trigger_legacy() is kept is because we
cannot create a new event for this, as we don't encourage developers
to created bulk events, for the reasons mentioned above.
I removed the call that gets the user record from the function
groups_remove_member() as it was not required and only appeared
to check if the user existed. It appears to be safe not to do
this check as nothing would fail down the line.
* Bulk unassign of groupings uses low-level API
As the previous commit, we keep the legacy event for now as it would
be wrong to create a new event to replace it.
Also, the code has been changed to call the low-level API to unassign
groups from groupins, even though at the moment there are no
events for that function.
* Bulk deletion of groups uses low-level API
Again, we keep the legacy event because replacing it would force
us to create a new event that does not make sense. See MDL-41312.
* Bulk deleting of groupings uses low-level API
* Asserting legacy event name in unit tests
* Minor SQL query and code improvements
