Hi, I have found another bug if I'm not mistaken in core data. When we are using a derived attribute in our xcdatamodel file after making the mapping file there is an error:
Can't find mapping model for migration
If you are looking to reproduce the bug I made a super simple example app at my branch in the link below:
https://github.com/hamed8080/LeitnerBox/tree/fix_migration
Keep that in mind if I remove the derived attribute and afterward make a migration with a new mapping file, it works correctly!
