When attempting to do an offline update to Plasma 6.8 with discover it crapped out about half way. This left the system in a broken state. Fortunately it did not prevent the system from booting and I ran Timeshift, restored the system to Plasma 6.7.5 and tried an online update. This also crapped out about halfway with a cryptic and less than useful error message. Timeshifted again to restore it back to 6.7.5.
So then I ran the update from the terminal
sudo apt dist-upgrade
to see where it was dying, and things went south shortly after it unpacked libcre, which is a crate (object library) associated with Rust. Reading through the error messages, it was complaining that “such and such package depends on libcre.yadda.yadda.yadda but libcre is not configured”. This goes on for 20 or so more entries then kicks out a message that read “Exiting due to too many errors.”
At this point I realized I could solve this by simply forcing the system to configure the existing updates which I did with:
sudo dpkg --configure -a
This has the effect of forcing the system to configure everything that needs to be configured. It completed successfully.
From that point I simply ran
sudo apt dist-upgrade
again which then installed the rest of the system successfully. Rebooted and I was now happily working in Plasma 8.