This is a bug fix for Entrance Exams management in Schedule & Details page.
The error is easy to reproduce:
You need to make sure that the following `FEATURES` flags are enabled:
Go to or create a new course, then go to "Schedule and Details" , enable an entrance exam for the course, you can leave the default score or change it.
Go to Content -> Outline and fill the entrance exam with a couple of courses, then create a normal unit in the course.
Go to the LMS and Enroll in the course with a new learner (without any staff privilege). You will only be able to see the entrance exam.
Go to Studio again, same course and then "Schedule and Details" change the enrollment date or any other data and save.
When you go back to the LMS, you will find out that the entrance exam is disabled now, and you can see all the course content, but in the "Schedule and Details" is still active.
What happens in the background, is that there is a bug in the settings handlers that is there is any pre requisite course set, iterates over all pre requisites and deletes them, but the problem is Entrance Exams are a type of pre requisite since they belong to the milestones app, and is getting deleted too.
The fix check the milestone namespace, and if it's an Entrance Exam skips it.
Co-Authored-By: Omar Al-Ithawi <email@example.com>