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

[Yavor Doganov]

Richard Frith-Macdonald wrote:
> On 20 May 2009, at 11:53, Yavor Doganov wrote:
> > The SONAME of a shared library should be bumped if and only if
> > there is ABI break
> 
> That's a matter of opinion.

Yes, the opinion of the library maintainer(s), which ideally should
conform to best practices.  The worst thing to do is to keep the same
SONAME when there's an ABI break.  Gratuitously bumping the SONAME is
not so bad, but it's a *big* annoyance to users and large binary
distributions who have to deal with library transitions, sometimes
inter-related and entangled in complicated ways.

> The fact is, most GNUstep libraries are still having to change.

No problem here.

> Even the base library needs to break binary compatibility
> occasionally in order to improve MacOS-X compatibility.
  ^^^^^^^^^^^^

"Occasionally", you say.  If I understand correctly, you say that
between 1.13 and 1.19 (for example) not all soname bumps were
warranted.  If so, we agree here, and that's the core of the problem.

Anyway, I am not qualified enough to argue with you -- someone with
enough spare time, skills and affinity to archaelogy could eventually
examine the diffs and prove/disprove the claim.

> Most ABI changes are minor and won't effect most applications ... but  
> we still need to change the soname because we don't know whether there  
> are apps out there which will break.

That's the right thing to do, indeed, iff there is ABI breakage.