[H-GEN] SMALL RPM PROBLEM

[Jason Parker-Burlingham]

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Greg Black <gjb at gbch.net> writes:

> Jason Parker-Burlingham wrote:
> 
> | Well that's just silly.  A package manager shouldn't let you do that
> | (just as dpkg doesn't; foo-1.3 is an upgrade and will replace
> | foo-1.2).
> Here we hit a real stumbling block for any package manager.  I
> have no idea how best to solve it, but I already know I don't
> like the "solutions" I have seen.
> 
> Just because I am installing foo-1.3, that doesn't mean I no
> longer want foo-1.2 and it certainly doesn't mean I want foo-1.3
> to suddenly prevent me from having continued access to foo-1.2.
> Any package manager that tries to enforce such rules is broken.

Yeah, I think that RedHat may have tried to address this in the past,
or maybe they still do.  I haven't touched one of their boxes in a
long time and I try to stick with what I know, to keep disinformation
to a minimum.

The trick here---and this is more for general edification instead of
being addressed to Greg---is that debs are named according a pretty
strict scheme, and as long as they don't conflict (through declared
metadata) or try to own the same files, you're dandy.

For the most part it works pretty well.  I have a couple of versions
of Python, and maybe two versions of Perl installed, and as
many as three versions of the same kernel (same source, differenent
.config files) installed at once.

However, unless we're talking about major infrastructure like Perl,
Python and kernels, or libraries, you are indeed pretty much out of
luck.  And there sure *are* times I'd like to be able to *not* have a
bunch of differing versions of the same program installed!

> In some cases, I build by hand from source because I'm a tester
> for the software (e.g., bash);

You use bash?  Somehow I had you marked for a C Shell user.

Oh dear.  No need for a shell advocacy thread, people!  Stand down!

> I'm not against package systems and I do use them extensively.
> I don't think they're perfect and I think they do some things
> really badly.

Yeah.  I learned how badly the Debian stuff sucks for me when I tried
to write some software that would automatically rebuild a package from
source as new versions arrived on a mirror.  Eugh.  (The problem's
mostly been solved, but it takes better minds than mine.)

I think the very real problem is that package managers suffer from
poorly designed interfaces, just like lots of other software.  A
design looks good on paper and it might even be implemented
properly---I think dpkg fits that bill---but even if that matches what
the user expects, it'll need to be future-proof, too.

> [1] The Python people did make some incompatible changes in the
>     syntax accepted by the parser

I'd be a little more horrified by those changes if Perl 6 wasn't
starting to look like a *whole new and different language* rather than
a (small or large) improvement on what went before.

jason
-- 
``I may have agreed to something involving a goat.''  -- CJ

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