I disagree. Being strict about the policy is a good thing - it gives you a predictable result.
That said, you could install zsh/release and that does do some switching of candidates to make that work. I don't like that. It also does not work entirely reliably. I just closed two or three of these bugs as Won't Fix or Invalid or something. One exception I'd consider to be a valid thing is to switch candidates of packages from the same source package, but that only helps for a limited number of problems. We are in desperate need of a new solver, and I hope to get https://salsa.debian.org/apt-team/apt-solver-kalel/ working eventually. But even there, by default, we're strict about policy. You'd get an option to relax policy and determine a best solution where there is no strict solution available. But that should require an explicit opt-in. I do not plan to backport that solver to older releases, except as an EDSP (external dependency solver protocol) solver. But solvers like that are remarkably slow. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to apt in Ubuntu. https://bugs.launchpad.net/bugs/1788486 Title: apt behaviour with strict dependencies Status in apt package in Ubuntu: Confirmed Status in apt source package in Xenial: Confirmed Status in apt source package in Bionic: Confirmed Bug description: [Impact] We notice that situation while investigating a security update using Landscape, but it also applies to 'apt' outside the Landscape context. 'apt' should be smarter to detect/install packages with strict dependencies such as systemd[1] when a version is specified for upgrade (Ex: $ apt-get install systemd=229-4ubuntu-21.1). It should automatically install the dependencies (if any) from that same version as well instead of failing trying to install the highest version available (if any) while installing the specified version for the one mentionned : ======================== $ apt-get install systemd=229-4ubuntu-21.1 .... "systemd : Depends: libsystemd0 (= 229-4ubuntu21.1) but 229-4ubuntu21.4 is to be installed" ========================= To face that problem : - Package with lower version should be found in -security ( Ex: systemd/229-4ubuntu21.1 ) - Package with higher version should be found in -updates ( Ex: systemd/229-4ubuntu21.4 ) - Package should have strict dependencies ( Ex: libsystemd0 (= ${binary:Version}) ) - The upgrade should only specify version for the package, without it's dependencies. (Ex: $ apt-get install systemd=229-4ubuntu-21.1" #systemd without libsystemd0 depends) Using systemd is a good reproducer, I'm sure finding other package with the same situation is easy. It has been easily reproduced with systemd on Xenial and Bionic so far. [1] debian/control Depends: ${shlibs:Depends}, ${misc:Depends}, libsystemd0 (= ${binary:Version}), ... [Workaround] If package + dependencies are specified, the upgrade work just fine : Ex: $ apt-get install systemd=229-4ubuntu-21.1 libsystemd0=229-4ubuntu-21.1 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/apt/+bug/1788486/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
