Hi! On Fri, 2010-04-30 at 12:56:08 +0200, David Kalnischkies wrote: > The problem: > To compare versions with the same version number apt generates > a hash over a few informations which are available online and > in dpkgs status file: all dependencies and the installation size. > (as these are likely to change if this is another version)
[...] > we can see that dpkg in his status file drops the zero-epoch. > This doesn't change the semantic as zero-epoch and no epoch are > considered equal, but as apt uses the string without deeper > parsing at this stage this is a big difference in the hash. > ( can be seen in apt-pkg/deb/deblistparser.cc VersionHash() ) The same problem arises with non-significant zeros before digits, for example: 0.001 == 0.1 == 00:000.1 Although this might be trickier to see in the wild, as dpkg itself would not normalize these versions, but an unknowing packager could generate those (somehow) thinking they are different. > Quick&Dirty workaround is to drop the zero-epoch in the package > so the Packages and status file are equal again. (cc'ed perl group > and last uploader, maybe they want to do that) > > The real solution is to either tell apt to strip out the zero-epoch for > the hash or to tell dpkg to not remove the zero-epoch in status. > It is relatively easy for apt to ignore the epoch for the hash as it is > a simple hash and we don't need to care about false positive removes > so apt still doesn't need to do expensive parsing here, but i want > to ask dpkg maintainers (cc'ed and titled to grep their attension) > for their opinion as this is maybe something they want to change > instead in their logic for consistence… > (through no zero epoch could be a change to be consistence…). I don't think dpkg should stop removing the zero-epoch, it would be redundant and confusing information. But it might be a good idea to make dpkg-gencontrol for example drop it on output. And it seems that apt might need to consider the other equivalent versions too. regards, guillem -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
