On 14 August 2017 at 13:48, Ralf Mardorf <silver.bullet@xxxxxxxx> wrote: > On Mon, 14 Aug 2017 14:03:45 +0200, mpan wrote: > >> why does a package from official repositories mentions what version > >> of a dependency is required? > >Because it may be that it is working only with that particular > >version. > > That doesn't explain why it is needed or in any way useful for a package > provided by official Arch repositories? Partial upgrades are > unsupported [1]. Actually it could be vary annoying, if packages now > start including the version of a dependency. I didn't notice that > packages mention dependency versions for at least the last 4 years [2]. > It's not the only dummy package I'm using for at least that long. > Yes, partial upgrades are unsupported, but in practice this still happens, usually not deliberately. For instance, I will quite often do a "pacman -S <package>" without doing a full system update first, assuming that *probably* nothing important has changed since the last update. It's a sloppy practice, but humans cut corners: it happens. When a plugin relies on a potentially unstable ABI (not many applications offer stable ABIs), specifying that the plugin package requires that exact version of the application will ensure that mistakes like this don't happen. If I see an error like "package x requires y=1.2.3" when installing a package, the first thing I'll try is a system update, an obscure segfault is avoided, and everyone's happy. So the failsafe does the job. It's good defensive practice by the packaging team, I think. Paul
