Bug#839182: postgresql-9.4-postgis-2.2 and postgresql-9.4-postgis-2.1 cannot be installed simultaneously

[Markus Wanner]

Control: tags -1 +confirmed

Hello Greg,

On 09/29/2016 11:59 PM, Greg Burek wrote:
> Is each version of postgis-scripts incompatible with other versions of
> postgis? 

Yes.

Longer answer: the base issue here is that PostGIS is a single
extension, so PostgreSQL wants exactly *one* file from a scripts package
that defines what to do for `CREATE EXTENSION postgis`. These scripts
packages all ship that one file, therefore they are not possible
co-installable and must conflict.

> Is postgis-2.3-scripts not backwards compatible with postgis-2.2?

If the extension is already created for a given database, PostgreSQL
doesn't need the -scripts package(s) at all. You could (in theory)
remove them.

In practice, we made the extension package depend on its exact -scripts
counterpart, which makes the postgresql-X.Y-postgis-M.N packages
non-co-installable as well. We need to fix that.

Thanks for your report, I wasn't aware of this issue so far.

Kind Regards

Markus Wanner