This issue is part of the course hierarch project.

Issue goals

Steps to reproduce:

1. Enable mod_subsection
2. Create a course with at least one subsection instance.
3. Disable mod_subsection
4. What should happen: the course is displayed.
5. What happens: it throws an exception.

The fix you also decide what happens with the delegated sections activities when mod_subsection is disabled. They could be:

• hidden from the course page.
• display the subsections as normal sections at the end of the course.
• Any other creative solution.

Update: the final decision from UX is to show the subsections as orphaned sections when mod_subplugin is disabled. This situation should be extremely rare and we already have an implementation for orphaned sections (they are treated as stealth sections with limited options).