When assign is configured to use separate groups, and team submission is switched off, then you once you try to switch to an empty group in a grading table, you get an error 'Coding error detected, it must be fixed by a programmer: moodle_database::get_in_or_equal() does not accept empty arrays'.
Steps to reproduce:
- Create a group with no members
- Create a grouping that includes that group
- Create an assignment with the following settings.
- Switch 'Team submission' to 'Off'
- Switch 'Group mode' to 'Separate groups'
- Select the grouping you created
- Make sure that 'available for group members only' is checked.
- Click Save and display
- Go to Grading table
- Choose your empty group in group selector
Expected result: It should display "Nothing to display"
Actual result: The following error occurs on a broken page.
The error also occurs when you select "None" as the grouping in the assignment settings. Then the error occurs immediately when you go to the grading page.