2015-09-22 20:40 GMT+01:00 Grześ Andruszkiewicz <gandr...@gmail.com>: > Hi, > > This problem occurs every time a new stable Debian is released. As a > workaround I always have to do aptitude dist-upgrade at some point (after > upgrading selected packages in a safe way).
It happens only with upgrades of releses since about the time that you reported this, or from much more long ago? (Say, 2005). > Now I am running Debian stable, so my APT policy is (600, 'testing'), (700, > 'stable'), (50, 'unstable') > > Unfortunately we just had a release, so the next opportunity to replicate > the problem will be in a few years time. What kind of debugging output > should I collect if/when it happens next time? I never experienced this myself because I haven't dist-upgraded in the last few years. I usually run systems with unstable/testing, and upgrade often and many times upgrading selected packages, as you said above, always guiding the solution interactively. Sometimes it takes a while to calculate solutions, but not more than a few seconds. Probably the information given is enough, I could attempt to reproduce it using older releases. The problem is to find time and gain experience to tackle it; there may be exactly one person in the world with enough experience in aptitude's resolver (his creator), and he left long ago. I think that the problem is that the possible universe of solutions is vast, like a game of chess or guessing passwords, and the resolver fails to find quick solutions. Problems that make this worse are things like enabling multi-arch or adding a full suite like unstable or testing -- doubles the number of packages (equivalent to growing the chess board, or guessing passwords with more characters), and the number of possible solutions for upgrades grows exponentially. If you upgrade from one vesion of stable to the next, and if you are not doing this already, probably disabling the other releases and keeping only stable it will help to cut down dramatically the number of solutions that aptitude has to explore. Maybe this still means many hours, though. And maybe previously installed packages (local, or of testing and unstable) cause some problems that make fully automatic solutions impossible or very costly to calculate. But still, it's the best advice that I can give for the time being. Cheers. -- Manuel A. Fernandez Montecelo <manuel.montez...@gmail.com>
