This achieves a massive clean-up. It simplifies comples code in a number
of places. It allows some methods and functions to be moved to a more
appropriate home (for example cannot_review_message to the quiz class).
It moves more logic out of the renderer.
This avoids the problem that you cannot send messages in transactions.
It also means that the quiz submission will not be prevented, and the
message will still be sent eventually, if any part of the messaging
system is giving intermittent errors when the student wants to submit
their quiz.
This was implemented by Matt Petro of the University of Wisconsin - Madison Engineering
School and Math Department. Many thanks. Reviewed by and committed by Tim Hunt.
This adds a new Overrides tab to the UI, with sub-tabs Group overrides and User overrides.
Each of those lists all the overrides that currently exist, and lets you manage them and
create more.
When a quiz is being attempted, the override that applies to the current user is combined
with the current quiz settings loaded from the quiz table (normally called $quiz).
If there are both user and group overrides, then just the specific user override is used (more specific).
If the user is in several groups, then the overrides are combined to give the most permissive set of options.
There is one new database table quiz_overrides, to store the overrides.
MDL-15537 - create oo attemptlib.php to hold shared code between attempt, summary and review.php
MDL-15541 - Refactor starting a new attempt into a new file startattempt.php
MDL-15538 - Rework attempt.php to use attemptlib.php
