When upgrading an extension to use mixins, existing managed entities get deleted
I noticed while working on https://github.com/systopia/de.systopia.eck/pull/53/commits/66e1be252f3743aad35c3d028b628f3ea721948d that when switching from the master branch (without mixins) to the working branch (with mixins) that upon clearing caches all managed entities would be deleted and recreated.
In some cases that's not a big deal, but in this case it's quite a problem because of cascading deletes. The option group is a managed entity, so all user-created option values get destroyed in the process!
It must be an order-of-operations thing, where the managed entities get reconciled before the info.xml
file gets scanned for mixins.