Re: GEOS 3.8.0

On Thu, 2019-10-10 at 11:48 -0700, Paul Ramsey wrote:
> FYI, fresh meat for the pipeline:
> 
> https://lists.osgeo.org/pipermail/geos-devel/2019-October/009342.html

I think something went wrong with packaging there, causing problems for
people who upgrade their PostGIS installation.

Here is an account of the problem I had at a customer:
https://stackoverflow.com/a/61494358/6464308

Essentially, it should be impossible to have both geos37 and geos38
installed, because they both ship the library "libgeos_c" with the same
library major version, even though the libraries are binary incompatible.

"libgdal.so.26" from "gdal30-libs" is linked with this library from
GEOS 3.8, but if GEOS 3.7 is also installed and happens to be first on
the shared library path, it pulls the wrong one and fails with

/usr/gdal30/lib/libgdal.so.26: undefined symbol: GEOSMakeValid_r

Now it is easy to fix the problem by removing "geos37", but I think
that the packages should avoid the problem.

I leave the best solution to your discretion, but these are my ideas:

- Add dependencies that forbid both packages to be installed at the
  same time.

- Make sure that the GEOS 3.8 lib directory is always first on the
  shared library search path.

Yours,
Laurenz Albe