[Ubuntu] GDAL reverse dependency rebuilds (was: GRASS 7.0.5 and the GDAL GRASS plugin)

[Sebastiaan Couwenberg]

On 10/02/2016 11:58 PM, Even Rouault wrote:
> Le dimanche 02 octobre 2016 23:53:47, Sebastiaan Couwenberg a écrit :
>> The incremented version in the build dependencies and the virtual GRASS
>> ABI package are required for the package in UbuntuGIS too. UbuntuGIS
>> still uses GDAL 2.1.0 instead of 2.1.1 as in Debian, so the GDAL version
>> does not need to be incremented nor should the 2.1.1 version from Debian
>> be used (updating GDAL to a new version requires a rebuild of its
>> reverse dependencies).
> 
> Just chimming in on this remark. Except if we mess up things, GDAL X.Y.z shoud 
> be binary compatible with GDAL X.Y.Z, even at the C++ level, so normally you 
> shouldn't have to rebuild reverse dependencies

The experience with gdal in Debian hasn't been that great, that's why
the packaging now using a virtual ABI package that changes for every
release (even micro/patch releases). The changes between 2.1.0 and 2.1.1
weren't very worrying (no removed symbols for example, only a couple new
C++ symbols), to be better safe than sorry a transition was still done
and all packages using any C++ symbols were rebuilt. The update to GCC 6
caused a number of symbols changes mostly related to pairs, the reverse
dependencies have not been rebuilt for that because no issues have
surfaced yet. It shows that not all C++ symbols changes break the ABI,
but also that tracking those changes is hard.

Having the C & C++ interfaces provides by separate libraries like GEOS
and libLAS do for example should help if all reverse dependencies manage
to limit themselves to C library, but experience with GOES & libLAS
shows that too many projects still use the C++ library.

Kind Regards,

Bas

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