transition: geos (spatialite->postgis->gdal->spatialite circular dependency)

[Sebastiaan Couwenberg <sebastic@xs4all.nl>]

On 17-08-15 21:50, Sebastiaan Couwenberg wrote:
> I've completed the rebuilds of first dependency level, we need to
> untangle the spatialite->postgis->gdal->spatialite circular dependency
> to make the build dependencies for all these packages installable with
> the new libgeos-c1v5 package.
> 
> gdal (1.10.1+dfsg-9 / 1.11.2+dfsg-1~exp4) cannot be built because the
> build dependencies cannot be installed. It at least needs spatialite to
> be rebuilt with the new geos to not pull in the old libgeos-c1.
> 
> [...]
> 
> postgis (2.1.8+dfsg-1) will also need gdal & spatialite to be rebuilt
> with the new geos packages before its build dependencies can be installed.
> 
> [...]
> 
> spatialite (4.3.0-1) needs postgis to be rebuilt with the new geos, so
> but postgis requires gdal & spatialite to be rebuilt first. To untangle
> this circular dependency we need to dropping the liblwgeom dependency to
> allow spatialite to rebuild with the new geos, after which we can
> rebuild gdal and postgis, reinstate the liblwgeom dependency in
> spatialite and rebuild spatialite & gdal again. Splitting liblwgeom into
> a separate source package may be an option with PostGIS 2.2.
> 
> I need to think this issue through some more. It's not specific to the
> GEOS 3.5.0 update, and affects 3.4.2 v5 libraries for the GCC 5
> transition too.

To deal with the spatialite->postgis->gdal->spatialite circular
dependency the process should probably be:

 * Upload geos to unstable to start the GCC 5 transition
 * Upload spatialite (4.3.0-2) to unstable, drops liblwgeom dependency
 * File RC bug on spatialite (4.3.0-2) about liblwgeom regression to
   prevent testing migration, and have the RC bug block the geos
   transition bug (#791045) too
 * BinNMU gdal with spatialite (4.3.0-2) in unstable
 * BinNMU postgis with rebuilt gdal & spatialite in unstable
 * Upload spatialite (4.3.0-3) to unstable, reinstates liblwgeom
   dependency
 * BinNMU gdal with spatialite (4.3.0-3) in unstable
 * BinNMU postgis with rebuilt gdal & spatialite in unstable

I'm CC'ing this message to the geos transition bugreport too, for
earlier messages in this thread on the debian-gis list see:

https://lists.debian.org/debian-gis/2015/08/msg00054.html

Kind Regards,

Bas

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