XMLDB Check indexes error

[levemar]

When you upgrade student quiz from an earlier version, and you go to XMLDB editor > Check indexes, it displays an error that there is a missing index.

To reproduce, in Moodle 3.11 (although you can have the same error after upgrading both Moodle and Student quiz from 3.11 to 4.x, it is easier to explain using a single moodle version) :

• Install studentquiz v4.6.0 (or some other earlier versions)
• In site administration, go to XMLDB editor and click on Check indexes
• Everything is fine for the state_history table :
  
• Upgrade studentquiz to v4.7.1 (for example)
• There are now some errors :
  
  

This probably has to do with this dropping of the index in upgrade.php

Maybe it was not the good way to drop the index? Or it indicates that something should also be changed in install.xml?

Thanks,
Marie-Eve