Re: [tlug] Well now I'm hosed - Dapper/Edgy died

["Stephen J. Turnbull" <stephen@example.com>]

Dave writes:

 > Dapper/Edgy died

Undoubtedly Edgy Eft just molted, and is hibernating until spring
arrives.  Then you'll meet again.  :-p

Godwin Stewart writes:

 > Dave, I know this comment doesn't help you, but your current
 > predicament with circular dependencies is the main reason I cannot
 > abide package-based distros.

The problem isn't packages, which can easily be source-oriented, as
several have pointed out.  It's dependencies themselves.

What Lusers want is automation, and what they desperately want to
avoid is thinking about their system(s).[1]  Luser-oriented distros
therefore *require* all prequisites for almost all features, and in
practice don't really support "recommend" or "suggest".  This requires
careful testing to avoid deadlocks, because it turns out to be
impossible in practice to avoid versioned prerequisites.  Apparently
it is the case that a small amount of testing will remove almost all
deadlocks, because Luser-oriented distros never have easy ways to
break them (at least not that are documented in the error messages
delivered by package managers).  This kind of setup is amenable to
binary packages, which are also very attractive to Lusers because
they're relatively fast to install.  The problem, of course, is that
if the automation fails, you're hosed; there's little support for
non-distro-developers to resolve problems.

AutoConfuse[tm] is basically a framework for implementing distros (eg,
GNU itself) that are source-based, with a diametrically opposite
approach to prequisites: if a prerequisite isn't present, then the
relevant feature will not be available in the package as built.  This
is an excellent way for someone who wants to run a really tight ship
to function, because configure scripts normally allow you to request
features, and will stop and tell you to install prerequisites for
requested features.  At that point you decide whether to do this or to
back off on the feature request.  The problem with this approach (at
the pure AutoConfuse level) is that things that really should be
automated (eg, fetching and building prerequisite packages) aren't.

What Debian (and its derivatives) are doing is to build more
intelligent dependency analysis into the PMS.  Unfortunately, they
aren't building display features into it.  (What I have in mind is
gitk from the Git version control system.[2])  I'm not sure what Red
Hat and Microsoft's Linux division do; I suspect that they have some
analytical tools but mostly depend on careful testing against the
release-in-progress.

What Gentoo and the *BSDs do is to start from the AutoConfuse strategy
and work forward, providing automatic download and build for
prerequisite packages.  Gentoo's portage is especially nice because
the USE flag system allows you to specify general characteristics of
the system that you want (eg, USE="-GNOME" to avoid the Generally Not
Operable Multimedia Environment), in a config file for defaults while
overriding them on the package install command line when you want.
(It's possible to do this in many cases with the pkgsrc-style
makefiles, but Gentoo makes it a *documented* feature.)

I think this latter approach is more robust in general, except that
the USE flag implementation isn't going to scale much farther as it
is.  (Too many use flags, too ill-defined, often not implemented in
any given package.)  The main thing that prevents this from being the
obvious way to go is that it's not very compatible with binary
packages, which is going to continue to be desirable for people with
lower-end systems.[3]


Footnotes: 
[1]  N.B.  This doesn't mean that Lusers are unintelligent or lazy; it
is often a rational choice to be a Luser.  For example, if you are
bucho or torishimariyaku, it's atarimae. ;-)

[2]  Sad, isn't it?  The kernel developers can work out those graphs
in their heads; it's Lusers in dependency-deadlock that really need
these tools.  *Usually* "dpkg purge --force <erroring-package>" will
work, but sometimes it's more complex than that.  A visualization of
the dependency graph would really help.

[3]  I gave a student with a 1.5GHz Celeron system and 256MB of RAM an
Ubuntu live CD; it took 45 minutes just to start OOo's Write.  She's
suddenly not very eager to use Linux....