Bug#950859: cegui-mk2: FTBFS with boost171 and new cmake and symbol changes

[Dimitri John Ledkov]

Yes there is a way.

You can provide libcegui-mk2-x.y.z-boost171
And then rewrite shlib deps to require a dep on libcegui-mk2-x.y.z-boost171
( >= X.y.z)

That way things that build against this new lib get the right dep, and
whenever cegui is NMUed for new boost Abi autochanges.

However, when you switch to this scheme either the library package needs to
change name, or you need to declare breaks on your reverse deps, to prevent
partial upgrade

Boost does similar to encode python versions and icu. And many other deb
languages do similar things like ocaml, gch, etc.

On Sat, 8 Feb 2020, 17:48 Olek Wojnar, <olek at debian.org> wrote:

> Hi Dimitri,
>
> Thanks for the bug report, and thanks for the patch!
>
> On 2/7/20 8:49 AM, Dimitri John Ledkov wrote:
> > Package: cegui-mk2
> > Version: 0.8.7-5
> > Severity: serious
> > Tags: patch
> > Justification: ftbfs
> >
> > Dear Maintainer,
> >
> > cegui-mk2 ftbfs with new cmake & boost1.71 due to change in cmake
> > policy w.r.t. boost version detection (it is now more normal). See patch
> attached.
>
> Thank goodness for them making it more normal! I was not a fan of that
> old system.
>
> > I am currently in process of migrating to boost1.71 in Ubuntu, which
> > has not started yet in Debian but is upcoming.
> >
> > When built against boost1.71 symbols are dropped and changed. It seems
> > as if cegui-mk2 re-exports boost symbols, and thus boost abi change in
> > templates leakes in the change of cegui-mk2 libraries ABI change.
> >
> > How should this be handled?
> >
> > Is there a new upstream release of cegui that we can package in
> > experimental, always built against boost1.71 with new symbols?
>
> No, upstream has not done a new release in a while. Although I can (and
> plan to) package the current version in experimental once boost1.71
> lands there. Since I don't follow Boost, a notification in this bug
> report would be appreciated.
>
> > Or shall i just blindly update the symbols file, rebuild ember and
> > hope for the best?
> >
> > How was this handled in cegui-mk2 before, when boost changed without
> > cegui-mk2 new upstream releases?
>
> I've only recently taken a more-active role in maintaining this package.
> I think I previously only submitted a few NMUs. But, I believe that what
> you listed is exactly what happened. I know I saw that with Ember (which
> I *have* been maintaining for a while).
>
> If you have any suggestions for a better, less-reactive, way forward on
> this I'm certainly open to it!
>
> > I would like to avoid diverging ABI between ubuntu & debian here.
>
> Absolutely! I'm a big fan of keeping Debian and Ubuntu closely
> synchronized.
>
> -Olek
>
>
>