On 2022-09-29 Guillem Jover wrote:
> On Wed, 2022-09-28 at 21:41:59 +0800, Jia Tan wrote:
> > […] The
> > interface for liblzma and xz for the multi threaded decoder does not
> > have any planned changes, so things could probably be developed and
> > tested using 5.3.3.
>
> Ah, thanks, that's reassuring then. It's one of the things I was
> worried about when having to decide whether to merge the patch I've
> got implementing this support into dpkg. So, once the alpha version
> has been packaged for Debian experimental, I'll test the patch and
> commit it.
There are no planned changes but that isn't a *promise* that there won't
be any changes before 5.4.0.
I don't track API or ABI compatibility within development releases and
thus binaries linked against shared liblzma from one alpha/beta release
won't run with liblzma from the next alpha/beta *if* they depend on
unstable symbols (symbol versioning stops it). This includes the xz
binary itself and would include dpkg too if it uses the threaded
decoder.
Sometimes it can be worked around with distro-specific patches but
that's extra hassle and can go wrong too. Please don't end up with a
similar result that happened with RHEL/CentOS 7 which ended up
affecting users of other distributions too (this is included in 5.2.7):
https://git.tukaani.org/?p=xz.git;a=commitdiff;h=913ddc5572b9455fa0cf299be2e35c708840e922
So while I encourage testing, one needs to be careful when it can
affect critical tools in the operating system. :-)
--
Lasse Collin
