Re: [Plplot-devel] Set the libplplotada_SOVERSION on the CMake command line

[Alan W. I. <Ala...@gm...>]

On 2020-11-15 07:36+0100 Rafael Laboissière wrote:

> Dear PLplot developers,
>
> Please find here attached a patch developed by Nicolas Boulenguez that we are 
> currently applying to the Debian package.  The patches regards the setting of 
> the libplplotada's shared object version.
>
> Here is the description of the patch, as written by Nicolas:
>
> “The SOVersion sometimes needs to evolve independently of the API (and thus, 
> is unrelated with semantic versioning), or even without knowledge by the 
> upstream author.  For example, a rebuild of the library with a different 
> compiler may break its ABI.
>
> This patch provides redistributors like Debian an easy way to set the 
> libplplotada_SOVERSION on the CMake command line, without patching CMake 
> files.
>
> This patch only affects the Ada library, but the suggestion applies to any 
> language allowing dynamic linking.
>
> As far as I know, the part added by _VERSION and the related symbolic links 
> are a complexity added by CMake (probably in order to follow the GNU libtool 
> conventions), but the linker only cares about the SOVERSION.”
>
> Please consider applying this patch to PLplot.

To Nicholas and Rafael:

I would be happy to cache *_SOVERSION variables for each of our
libraries to help packagers who are up against some ABI change for
their distribution.  However, packagers also would need to update the
*_VERSION variables as well if their distribution mandated some rule
for those such as semantic versioning (which is the set of library
SOVERSION/VERSION rules that libtool has adopted).  For example, if
*_VERSION remains uncached as now, then the VERSION result will
combine the packager's SOVERSION with a default suffix that is
consistent with the semantic versioning rules (e.g., the ".2.0" suffix
in ${plplotfortran_SOVERSION}.2.0) for the default SOVERSION supplied
by PLplot but *not* the SOVERSION supplied by the packager.  So I am
strongly leaning toward caching both *_SOVERSION and *_VERSION
variants of all library version variables.

@Nicholas:
Thanks for (indirectly) bringing this issue to our upstream attention.

@Rafael:

Historically (back in our autotools days) you were the PLplot guru on
library soversion/version issues.  So I would appreciate a comment
from you about whether you see any downside to my idea above to cache
both forms of library version variables to allow packagers to override
both.

@both:

Best wishes,

Alan
__________________________
Alan W. Irwin

Research affiliation with the Department of Physics and Astronomy,
University of Victoria, Victoria, BC, Canada.

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.org); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
__________________________

Linux-powered Science
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