comps discussion at fudcon and the future

seth vidal skvidal at fedoraproject.org
Wed Jan 14 21:12:30 UTC 2009


On Wed, 2009-01-14 at 16:08 -0500, Josh Boyer wrote:
> On Wed, Jan 14, 2009 at 02:51:52PM -0500, seth vidal wrote:
> >
> >On saturday at fudcon we had a small talk (meaning there were only 4 of
> >us there: Jeroen, Jeremy, James, and Me) about the future of comps and
> >what we need.
> >
> >We came up with a fairly radical departure that will take some work to
> >implement and probably won't land for F11 but it is worth discussing a
> >bit now. Please read through the whole thing before jumping all over it.
> >
> >
> >Problems we see:
> >- browsing packages is a difficult problem when you have 10000+ pkgs.
> >- comps has a lot of meanings and it is not obvious what they all are/do
> >- conditional pkgs (which provide a way of saying "install pkgX only 
> >  if pkgY is installed) are several colors of doom b/c they aren't a 
> >  dependency relationship and creates clutter on systems.
> >- users expect groups to be more persistent on their systems and to act
> >  more like pkgs (ie: yum update should update groups, too)
> >- optional/default/mandatory pkgs are confusing and not useful to most
> >  people - the types are only useful when browsing, not when installing.
> >
> >
> >We're still going to have a comps/groups file in the metadata but we'll
> >be removing package types. If a package is a member of a group then
> >that's it. It's in the group.
> >
> >When someone goes to install the group: 'yum groupinstall
> >mygroup-of-fun' or 'yum install @mygroup-of-fun' then yum will grab the
> >comps/groups file from each repo, look if the group you're requesting is
> >there. If so it will create a metapkg rpm (a package containing only
> >requirements) on the packages that exist in the repositories that are
> >listed in that group. Then it will depsolve and install that pkg. The
> >package name will be @mygroup-of-fun. The package version will be a hash
> >of the contents of the package along with a timestamp. It needs to be
> >timestamp-based so the version is increasing so we can 'update' these
> >pkgs.
> >
> >We'll make sure that yum knows about @pkgs to be looked up against the
> >comps file (which should be  significantly smaller now).
> 
> Bear with this question, but...
> 
> I often find myself doing "yum install <some group>" and messing around
> with that a bit.  Then I typically find that I only really want 1/2 the
> group or something.
> 
> With the metapkg installed, won't I have to yum remove that in order to
> remove any individual packages from in that group?  If so, will yum go
> into a depsolving erasure spree and try to remove the whole group
> instead of just the package or two I listed?

No, not if the remove-with-leaves plugin is not installed.

Remember:

yum install foo

foo requires bar
so bar is installed.

yum remove foo

only foo is removed. bar stays, unless you have remove-with-leaves
installed.


-sv





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