On 07/10/2021 11:01, Jakub Jelinek wrote:
On Thu, Oct 07, 2021 at 11:56:45AM +0200, Andreas Schwab wrote:
On Okt 07 2021, Alastair McKinstry wrote:
I strongly advise against this -- identical SONAMEs for the libraries on
all architectures is a key assumption on all Debian-based distributions
and designs
Even glibc has differing sonames on some architectures. And libgcc_s,
too.
Yeah, lib[cm].so.6 on most arches and lib[cm].so.6.1 on ia64 or alpha.
At least on Fedora I don't see a problem having libgfortran.so.5 on
most arches and libgfortran.so.6 on ppc64le. And then next year or two/3
switch to libgfortran.so.7 everywhere.
SOVERSION (Major release) (and hence SONAME) change tracking are key to
tracking the task of rebuilds/porting when incompatible changes happen
in libraries
(see https://release.debian.org/transitions/ and
https://wiki.debian.org/Teams/ReleaseTeam/Transitions for examples of
the process).
lib[cm] on ia64 and alpha work in that libc has not changed major
version in many years, and neither ia64 or alpha are currently "release
candidates" in Debian, which we need to keep rebuilds in sync. Even so,
the exception handling needed for them is a wart seen across the distro
dependency trees.
To make upgrades work, we have policy that it's possible that two
versions of a library with different SONAME can co-exist on a users'
system (package libgfortran5 "just" ships the libgfortran.so.5 file,
libgfortran6 can co-exist with it), but a given source package only
provides one of these library packages, and there is only one -dev
package (eg libgfortran-dev pointing libgfortran.so -> libgfortan.so.6).
A transition (eg gcc-11 to gcc-12 moving into the 'testing' staging
distro) updates libgfortran-dev to point to 6, drops libgfortran5 from
the Debian archive (but doesn't delete the package libgfortran5 from the
users' computer) and we rebuild and transition simultaneously all
packages that depend on libgfortran5.
So if we introduce libgfortran6 for ppc64le (with potential ABI changes
such as KIND) we rely on libgfortran5 disappearing for our transition
scripts to work, and testing the transition process. We can special-case
it just for one arch/package but its significant work and really painful.
A simple soname/soversion transition across all archs is much preferred.
Jakub
Alastair
--
Alastair McKinstry, <alast...@sceal.ie>, <mckins...@debian.org>,
https://diaspora.sceal.ie/u/amckinstry
Misentropy: doubting that the Universe is becoming more disordered.
