Passing the same object means enrol_cohort does not recognise a change
in role when an edit or batch course upload operation is done.
* enrol/editinstance.php was modifying $instance before passing it to
enrol_plugin::update_instance() so the latter never sees a difference
versus $data. This is redundant since update_instance() is doing the
same thing a second time.
* admin/tool/uploadcourse/classes/course.php is passing the same object
as both arguments to enrol_plugin::update_instance().
There is an expectation that update_enrol_plugin_data() is to mutate its
$instance argument and then return it based on how derived classes in
enrol_guest and enrol_self behave, so cloning $instance within
update_enrol_plugin_data() before mutating it isn't an option.
Jonathon Fowler
1a3a89b90f