Matt Zimmerman wrote:
> Practically speaking, the differences in compatibility between Ubuntu and
> Debian is of as much concern as those between Debian stable and Debian
> unstable. New interfaces are added in unstable constantly, and software is
> adapted to use them. Binary packages from unstable are rarely installable
> on stable without upgrading other supporting packages. Third party
> packagers must choose whether to provide builds for stable (if the package
> builds), unstable or both. So far, this has not resulted in a problem for
> Debian.
Except unstable is capable of running packages built on stable, and
stable is to some extent (partial upgrades) capable of running packages
built on unstable. And if it doesn't work, a dependency will tell you it
doesn't work. And Debian is able to decide we want to make it work better
and fix things. So I don't think your analogy holds up very well.
> The cost of guaranteeing ABI compatibility is high, and the benefit to free
> software is marginal. It is a problem for proprietary software vendors to
> be concerned with, and we should leave it to them. We have more important
> work to do, and we're doing it in source code form.
If I were only interested in source code, I would not be a contributor
to this distribution. I am interested in whole, working systems which
are accessible to end users.
> "Debian packages just work, in the environment for which they were intended"
No, Debian packages just work, if dpkg allows you to install them on
your system.
Unless, now, they happen to be built by someone running the other
distribution.
> This has nothing to do with binary compatibility, and everything to do
> with rigorous packaging practices (which is the true basis for this
> selling point).
I agree that ABI compatability is only part of the picture, though it
seems like one of the more important parts. However, the other parts of
the picture suffer from similar problems.
Just as a random example, Ubuntu's fork of debhelper has a hack[1] in
dh_buildeb to run pkgstriptranslations, an Ubuntu-specific command which
removes mo files from usr/share/locale. That works ok until Debian adds
a pkgstriptranslations that does something else. Or until the Debian
version of debhelper is installed on someone's Ubuntu system and begins
building packages without calling this tool.
> It has never "just worked" to mix and match binary packages from
> different releases of Debian, or packages from different Debian
> derivatives.
No other distribution has ever seen the need to fork debhelper (and
modify/fork 1500 other packages), or recompile the entire Debian archive
from scratch. No other distribution except perhaps Knoppix has attracted
enough users and developers to make compatability issues more than minor
annoyances. People didn't start talking about "rpm hell" until Mandrake
or the like showed up.
--
see shy jo
[1] which I would not accept into debhelper if asked because it violates
design principles of dh_builddeb
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