Re: ABI Compatibility (was Re: Installation woes for the average user...)

[Yavor Doganov]

On Wed, May 20, 2009 at 11:24:39AM +0100, Richard Frith-Macdonald wrote:
> I think what you are describing (as the correct way to do things) is  
> what GNUstep already tries to do ... see 
> http://mediawiki.gnustep.org/index.php/GNUstep_release_policy for the 
> actual release policy details.

On the contrary -- this very policy is the problem.

The SONAME of a shared library should be bumped if and only if there is 
ABI break, not because of publicity reasons, big API additions, or 
anything else.  You can continue to version stable releases with even 
numbers and unstable releases with odd numbers and release them in any 
order you feel apropriate; the SONAME has absolutely nothing to do with 
the package version.

>>> How you version the releases and what is considered
>>> "stable" and "unstable" is completely orthogonal to the library
>>> versioning.
>
> is technically true, it's not what people expect in practice, and  
> therefor not policy.  The policy is to keep the main so version numbers 
> in sync with the main release version numbers, because that matches 
> normal expectations.

Name just one library -- just one -- on your GNU system that behaves 
this way.  Consider what would happen if glibc or glib/gtk+ bump the 
soname every six months...  I find it incredibly hard to believe that 
this is "normal expectation".

> However, I don't think there have been any recent releases which should 
> have changed the so number for any of the libraries.

I've made an experiment some time ago by altering the symlinks without 
recompiling anything.  Every GNUstep app in Debian worked out of the box 
(of course that's not a 100% proof that the new Base/GUI were ABI 
compatible).