Re: Debian Family, GNAT version map

[Ludovic Brenta <ludovic@ludovic-brenta.org>]

Patrick writes on comp.lang.ada:
> I was hoping you would reply :)
>
> So I did as you had suggested and ran dpkg -l gnat*.
>
> I am on Xubuntu(I am planning on switching) and I got this:
>
>
> :dpkg -l gnat*
> Desired=Unknown/Install/Remove/Purge/Hold
> | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
> |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
> ||/ Name           Version        Description
> +++-==============-==============-============================================
> ii  gnat           4.6ubuntu1     GNU Ada compiler
> ii  gnat-4.6       4.6.3-1ubuntu4 GNU Ada compiler
> ii  gnat-4.6-base  4.6.3-1ubuntu4 GNU Ada compiler (common files)
> ii  gnat-gps       5.0-6          integrated development environment for C and
> ii  gnat-gps-commo 5.0-6          integrated development environment for C and
> ii  gnat-gps-doc   5.0-6          integrated development environment for C and

[I removed the lines concerning packages not installed on your system]

> The part here that worries me is the 4.6.3-1ubuntu4 portion. I am
> guessing other downstream Debian derivatives do not just take the
> prebuilt "debian-debian" binaries wholesale but instead recompile the
> sources again.

Not only that, they also occasionally change the sources; that's why
they introduce a new version number.  The other potential problem with
derivatives is their disregard for the release cycles of Debian.  I plan
and do all of my work so that each *stable* release of Debian contains a
consistent and (as far as feasible) bug-free Ada platform.  However,
between releases, there is no guarantee that the packages in Debian
*unstable* or *testing* are consistent with one another.  This is
particularly true between the time I upload a new gnat (the first
package in a transition) and the time I upload gnat-gps (usually the
last package in a transition because it depends on many other packages).
So, if a derivative distribution takes a "snapshot" of Debian unstable,
what you get might really be very... unstable.

FYI, here is what I have on my Debian testing, upgraded today:

ii  gnat             4.6      GNU Ada compiler
ii  gnat-4.6         4.6.3-5  GNU Ada compiler
ii  gnat-4.6-base    4.6.3-5  GNU Ada compiler (common files)
ii  gnat-4.6-sjlj    4.6.3-5  GNU Ada compiler (setjump/longjump runtime library)
ii  gnat-gps         5.0-12   integrated development environment for C and Ada
ii  gnat-gps-common  5.0-12   integrated development environment for C and Ada (common files)
ii  gnat-gps-dbg     5.0-12   integrated development environment for C and Ada (debugging symbols)
ii  gnat-gps-doc     5.0-12   integrated development environment for C and Ada (documentation)

> It may be hard to know if the package is now the same as the 4.6.3
> Debian version. If the packager had trouble with something they could
> modify something and introduce bugs.

No, it's not hard to know.  If the version number is different then the
package is different.  Read /usr/share/doc/gnat-4.6/changelog.Debian.gz
to know what the downstream packager changed.

> Do you have any suggestions on how to track combat version skewing or
> is this largely a non-issue?

Ubuntu has introduced subtle problems in the past but recent releases
have been fairly solid AFAICS.  I cannot be positive because I receive
almost no feedback from Ubuntu users or packagers.  So, use Debian
stable and stop worrying about forced upgrades :)

You can also use Debian testing part of the time (i.e. before a
transition starts and after it is complete).  Usually I announce the
transition starts and ends here on comp.lang.ada and on
debian-ada@lists.debian.org.

> It would be pretty easy for me to set up a bunch of distros under
> VirtualBox and then run dpkg -l gnat* on them but I guess it may not
> be that easy...

VirtualBox is overkill, you can use chroot instead, see
http://lists.debian.org/debian-ada/2010/02/msg00003.html for a recipe.

-- 
Ludovic Brenta.