Re: Debian Family, GNAT version map

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

Vasiliy Molostov writes on comp.lang.ada:
> Patrick писал(а) в своём письме Tue,
> 14 Aug 2012 11:17:47 +0400:
>
>> I am running xubuntu(I am a gnome 3 refugee ). I just encountered
>> this bug: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=564232
>>
>> I just installed debian as a VM and it is already fixed there.
>>
>> There are so many versions of linux and even so many debian
>> variations. I am wondering if anyone has tried to document the
>> different versions?
>>
>> I could try to put together some sort of list?

Debian has a "Derivatives Census" [1] where maintainers of derivatives
can volunteer to document their work.  However, the nature of free
software means there is no way to be sure that all derivatives are
listed there.

[1] http://wiki.debian.org/Derivatives/Census

This census contains no derivative aimed for Ada programmers.  The only
distribution that is specifically designed for Ada programmers is Debian
itself.  Thus the support for Ada in every derivative will, by
definition, lag behind that in Debian.

>> gnatmake --version does not give the specific build, is there a flag
>> for this?

dpkg -l gnat*

> I have used libre.adacore.com GNAT, downloaded by hand and installed
> by GNAT script on ubuntu distro (both 64 & 32 versions) and was able
> to build polyorb without any problem - got all examples working.
>
> Only one thing I have got erroneous was TLS dependency on libssl.a
> against libssl.so (2011, don't know as of 2012 since only just have
> upgraded for now)
>
> I wonder what they are doing in the debian with packaging so these
> become unstable?

The GPL Edition from AdaCore contains a coordinated snapshot of the
sources of everything, notably the compiler and PolyORB which are very
tightly coupled.  PolyORB relies on special support for Annex E built
into the compiler and runtime library.  This works well for those who
can and will recompile most everything from source and accept the pure
GPL for the Ada runtime library.

Debian does not use GNAT GPL Edition, instead it uses the GCC compiler
from the Free Software Foundation, whose runtime library grants the
Runtime Library Exception.  The relase cycle of the FSF is different
from that of GNAT GPL Edition; thus no release of GCC from the FSF is
identical to any GNAT GPL Edition (see Debian Policy for Ada, section
2.3.4[2]).

[2] http://people.debian.org/~lbrenta/debian-ada-policy.html#Timeline-of-GNAT-releases

Because of the tight coupling between PolyORB and GNAT, no PolyORB GPL
Edition can work out of the box with a release of GNAT from the FSF.
Some patching is always necessary.  The PolyORB pakage maintainer
chooses a revision of PolyORB from AdaCore's Subversion repository (as
opposed to a GPL Edition) so that it matches the FSF compiler better.
This is explained in the changelog of the polyorb package in Debian:

   * new upstream version : 2.8~20110207 (Subversion revision 170156) chosen
     because it immediately precedes a change of
     System.Partition_Interface.PCS_Version, which requires gnat > 4.6.
     - use 0f4393e4f6d42f8d093a29b8fa35aebf4eb4a5f4 from
       com.adacore.polyorb.debian

However the PolyORB maintainer, Xavier Grave, goes to great lengths that
this package is very stable; IIUC he uses it in mission-critical
programs (narval).

-- 
Ludovic Brenta.