Bug#387706: - splitting mesa and mesa-legacy for libosmesa

[Yann Dirson]

Summary of the situation: libosmesa6 (offscreen opengl rendering)
is currently included inside
libgl1-mesa-swx11 (source: mesa) and libgl1-mesa-glide3 (source:
mesa-legacy).  Both packages conflict with any other libgl1 provider,
most notably libgl1-mesa-glx, which is a must-have on most modern
desktop boxes.  Thus, installing any package willing to do offscreen
rendering forbids the use of accelerated opengl for most of the world.

To make things worse, a libopengl6 package already exists, containing
what looks like very special-purpose versions of the lib using different
sonames, but I think we can mostly leave this as is (I just plan to
slightly improve the description so people stop being confused about it).

I have started to work on a package split for both mesa and mesa-legacy,
creating new packages libosmesa6-swx11{,-dev,dbg} and
libosmesa6-glide3{,-dev,dbg}, in which to move the relevant pieces from
libgl1-mesa-*.  Unfortunately, since the new package depend on
libgl1, we cannot add a compatibility depends libgl1-mesa-{swx11,glade3}
to depend on them: that means binNMU's won't be enough, source uploads
will be needed for packages using libosmesa.

Now for the impacted packages.  Looking for current libOSMesa.so.6 shlibs
entry in sid yields:

$ grep-aptavail --pattern='libgl1-mesa-swx11 | libgl1-mesa-glide3' -s Package
Package: tulip

That seems to mean I am the only one impacted (which should explain why
I am the first to raise the issue :).

OTOH, the shlibs line was fixed only recently, and it may be that some
packages have not been rebuilt already, and thus would have broken deps
at present.  I do not know of a tool to check that however, so I'd think
we could just suppose there aren't any of them.

I have a patch for mesa already (needs to update for yesterday's NMU),
mesa-legacy remains to do, but that'll be mostly a matter of
cut'n'paste:

mesa (6.5.1-0.1.1) unstable; urgency=low

  * Split libosmesa material into their own package (Closes: #387706):
    * new libosmesa6-swx11 along with -dev and -dbg.
    * libosmesa6-swx11 shlibs point to -glide3 alternative, to be provided
      by mesa-legacy 6.2.1-8.2.
    * declare new packages to replace relevant versions of packages which
      provided them (libgl1-mesa-swx11*, libgl1-mesa-glide3*)
    * replaces/conflicts with libosmesa6-glide3*.
    * remove debian/libgl1-mesa-swx11.shlibs now unneeded, in favor of
      dh_shlibdeps -V like what is done for other packages.  
  
  * Adapted package description for libosmesa6{,-dev} to make it more
    obvious they are not the standard libOSMesa libs.
  * Fixed dh_makeshlibs call to avoid false-positives due to common prefix
    in package names, by anchorint grep matches to end of line.

 -- Yann Dirson <dirson at debian.org>  Sat, 14 Oct 2006 15:23:29 +0200


I guess it's time to request wider feedback :)
-- 
Yann.