Re: Preparing to release 0.9.12

[Isaac <idunham@lavabit.com>]

On Thu, Jul 25, 2013 at 07:59:55PM +0300, Timo Teras wrote:
> On Thu, 25 Jul 2013 12:16:55 -0400
> Rich Felker <dalias@aerifal.cx> wrote:
> 
> > On Thu, Jul 25, 2013 at 10:44:59AM +0300, Timo Teras wrote:
> > > On Wed, 24 Jul 2013 16:02:21 -0400
> > > Rich Felker <dalias@aerifal.cx> wrote:
> > > 
> > > > The list of changes since 0.9.11 has grown quite large, and
> > > > although we haven't met some of the roadmap goals for 0.9.12,
> > > > others that were marked for 0.9.13 have already been finished. So
> > > > I think it's reasonable to aim to release very soon now. There
> > > > are still a few pending items I'd like to get committed before
> > > > the release:
> > > > 
> > > > - orc's getaddrinfo fix for AF_UNSPEC with NULL hostname
> > > > - Andre's ARM memcpy optimizations
> > > > - New crt1.c code for adding PIE support for more archs
> > > > - MAYBE the symlink direction issue...
> > > 
> > > Since the C++ ABI was fixed, it means that any current native musl
> > > toolchain will get C++ ABI breakage?
> > > 
> > > In this case the symlink direction issue would help with smoother
> > > transitions. It would be also crucial to start using proper SONAME
> > > versioning, so we could handle binary upgrades smoothly.
> > 
> > This would not help. The ABI between the application and musl's
> > libc.so has not changed since just after the initial public release,
> > except for some bugs that had arch-specific structures laid out wrong,
> > etc. -- and in this case, programs built before the fix were not
> > working at all anyway when using the affected feature.
> 
> The so versioning will not help for C++ related things. The most
> important use case I had in mind is that, package managers that use
> soversions for automatic dependencies, can insert proper "require
> version XXX or later of this .so". That is, if we built with musl X, we
> can detect that from .so, and record it. And later ensure that musl X-1
> will not satisfy the newly built package's dependencies. Especially
> important when we are introducing new symbols.
 

On Debian, there's the "symbols" system; this lists all symbols with the 
version they appeared in, and the tools look through the symbols and 
find the lowest version providing all the symbols.

But as a standard rule, _added_ symbols _do_ _not_ call for a new SONAME,
since they do not break the ABI.


--
Isaac Dunham