On Tue, May 18, 2010 at 06:41:59PM +0200, David Kalnischkies wrote:
> No problem, i didn't understand me currently, too. ;)
> Just to add a bit more confus… clarification - i will
LOL
[ several APT/dpkg lists containing <awesome,1> package ]
> Communicating this to the converter seems at least for me a bit
> complicated as the converter will not know what the manager handles as
> the same and as a different version (and vice versa?).
Right, I now clearly see your point and the underlying problem (which I
missed before, thanks!). Let me rephrase to make sure we have the same
understanding of the issue:
« given that the package <p,1> (name, version) can appear in more than
one "package list", the fact that the solver will reply "install
p=1" is meaningless, as the upstream package manager won't know
*which* <p,1> it has to install »
My first temptation would be to say that individual package lists should
contain UUIDs, so that the downstream solver can annotate his solution
with those and the upstream package manager will be able to disambiguate
installation indication. Pragmatically, we don't have hopes to change
this soon, so we need another solution.
I see a solution that still preserves the "one pass" approach, not
adding any need of and ping-pong between package manager and solver. The
idea is that in the answer from the solver, you get package stanzas as
follows:
package: foo
version: 1.2.3-4
id: adgf31452135hkashdfa
installed: yes
The idea is that "id" is an optional property (defaulting to "") and
that the triple <package, version, id> uniquely identify a package for
APT; i.e.: it will be able to discriminate among multi-arch,
locally-rebuilt packages, and packages coming from different APT lists.
The point is now obviously which kind of 'id' should be used to ease
interaction with APT and friends. I see at least the following
possibilities, no idea what would be the most preferable:
1) id is the sha1/md5/... of the file the package comes from
2) id is the argc (on the cmdline) of the file the package comes from
3) id is the path of the file the package comes from
The advantage of (1) is that APT (I guess) already has some checksum of
packages list out of the APT-secure stuff, no idea whether they are
easily associable to individual packages though. Also, I don't know
whether some checksum of /var/lib/dpkg/status is available already or
not.
(2) is pretty damn easy and quite compact.
(3) is easy but not compact.
Would something like the above work?
Any other options?
Cheers.
--
Stefano Zacchiroli -o- PhD in Computer Science \ PostDoc @ Univ. Paris 7
zack@{upsilon.cc,pps.jussieu.fr,debian.org} -<>- http://upsilon.cc/zack/
Dietro un grande uomo c'è ..| . |. Et ne m'en veux pas si je te tutoie
sempre uno zaino ...........| ..: |.... Je dis tu à tous ceux que j'aime
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