Issues:
1. Fix setType calls
2. Changing from default to all and editing again, default is still selected.
3. Uncheck all options causes error.
4. Doesn't seem to be restricting based upon option.
5. Picked all and got coding error with the database thing.
6. Bad title: https://github.com/samhemelryk/moodle/commit/wip-MDL-37500-m25#L1R157
7. Amend comments - should only be removed once 2.5 is the minimum version for an upgrade.
8. Document the defaultsharing option.
Outcomes:
1. Fixed - copy paste error.
2. Fixed - mforms was applying the default value despite a value being provided. A quirk of elements with array names.
3. Fixed - validation now requires at least one option to be selected.
4. Fixed - issue rose from definitions not being re-parsed. cache/admin.php now reparses the first time a user visits the page.
5. Fixed - better purging of definitions when working with them anonymously. Unit test added.
6. Fixed - new string added and used.
7. Fixed - comments amended.
New issue to address parsing of definitions during upgrade.
New issue to add debugging notice if definition sets only one possible sharing option and that option is user input.
get_plugin_list was calling clean_param($pluginname, PARAM_PLUGIN) a
lot (600+ times per page), and that is much slower than you would guess.
A specific function for this case, (which we then also use from
clean_param) is a performance win.
Bug: There was no way to create an instance of a lock plugin for use
within Moodle.
Solution: Implemented management interfaces as part of cache/admin.php
to allow for instances to be added and deleted.
This was done in along the same lines of adding store instances.
This change is a large change to the way sessions are handled
within MUC after it was discovered that session did not function
as expected when any store other than the default session store
was being used.
As part of this change the session loader has been largely
customised in order to consolidate session data for the loader.
The unit tests have also being greatly increased to provide
better coverage for sessions.
