>From what I see, the real problem here is that plasma-discover's "upgrade" functionality is acting like a "aptitude full-upgrade", removing whatever's necessary, possible removing half your system, instead of acting like a "aptitude safe-upgrade", which would hold the problematic packages, and not remove anything.
Obviously, the second way would be much safer, and it would still result in a proper upgrade on Debian Stable, or in the other suites as long as there are no big migrations happening. The thing is, a user upgrading with this program, might end up destroying their system. I'd consider this 'grave'. Also, the OP for this bug is not the first one to have this same catastrophe happening. I remember someone on #debian-kde or #debian-qt-kde with this same problem, and rightfully, hating plasma-discover's guts. Cheers! -- Development blog: https://jancoding.wordpress.com
