Re: HEADS-UP: Library version number bumps

On Wed, Sep 29, 2004 at 07:27:10PM +1000, Tim Robbins wrote:
> On Tue, Sep 28, 2004 at 11:05:46PM -0400, Ken Smith wrote:
> > 
> > >From the "Better late than never" Department...
> > 
> > It looks like we should probably bump the version of a couple of
> > the system libraries.  With LOTS of help from Kris it looks like
> > this is the list we think needs a version bump, with the version
> > from 4.X being placed in compat4x:
> > 
> >        libgnuregex.so.2
> >        libhistory.so.4
> >        libm.so.2
> >        libncurses.so.5
> >        libopie.so.2
> >        libpcap.so.2
> >        libreadline.so.4
> >        libwrap.so.3
> > 
> > The bumps will be coming soon...
> 
> Why do they need to be bumped? Why use the version from 4.x? It sounds like
> this will break a lot of 5.x binaries.
> 

They need to be bumped because the internal workings of the libraries
have changed in such a way that a 4.X executable will either be
un-dynamically-linkable, will fail ungracefully (seg-fault, etc),
or (worse) run but it makes assumptions that are no longer valid
thus producing incorrect results.  By putting the older versions of
the libraries in the compat directory the dynamic linker will find
and link to those instead when starting the executable and since we
will have taken them from a 4.X system the executable should run just
fine.

Normally development cycles are "much more sane" (Scott's usual phrasing
for it :-) so at least in theory they're much shorter, and we don't
usually have as many "end-user-type-people" using a development branch
as we have now with the 5.X series.  So the fact we do this sort of thing
hasn't been a huge issue before - the developers should know how to cope
with it.  You're right - there can be 5.X based binaries that will have
problems.  At this point we need to decide which old executables break
and we're opting to break the 5.X executables - at least those users
had a little bit of a warning they were using a not-for-production-use
system.  We're not particularly happy about needing to do this.

-- 
						Ken Smith
- From there to here, from here to      |       kensmith_at_cse.buffalo.edu
  there, funny things are everywhere.   |
                      - Theodore Geisel |