[postgis-devel] Making SFCGAL mandatory

[Regina Obe]

> -----Original Message-----
> From: postgis-devel [mailto:postgis-devel-bounces at lists.osgeo.org] On Behalf
> Of Sebastiaan Couwenberg
> Sent: Monday, November 12, 2018 1:57 AM
> To: postgis-devel at lists.osgeo.org
> Subject: Re: [postgis-devel] Making SFCGAL mandatory
> 
> On 11/12/18 7:38 AM, Darafei "Kom?pa" Praliaskouski wrote:
> > This year Ubuntu Bionic was released without SFCGAL because of build
> > failures for last release.
> >
> > As a consequence, we can't assume anyone with recent distro will have
> > SFCGAL-enabled PostGIS until year 2023, when Bionic is End-Of-Life.
> 
> Where "distro" means Ubuntu.
> 
> There are more distributions out there with and without sfcgal.
> 
> Debian stretch has it, and Debian buster will have it too unless something
> breaks sfcgal between now and the freeze in a few months.
> 
> > I propose changing PostGIS build so that it requires SFCGAL, but that
> > dependency can be switched off by --without-sfcgal, much like it is
> > already with raster, so that this story doesn't repeat, or at least
> > there is some more visibility of the issue on the packaging side.
> >
> > Any objections? :)
> 
> Yes!
> 
> SFCGAL is too fragile to be a mandatory dependency of PostGIS. It also lacks
> upstream development.
> 
> Until those issues are resolved, it cannot be a required dependency of PostGIS
> unless you want to risk distributions to not ship with postgis due to CGAL
> updates breaking SFCGAL again.
> 
> If that would affect RedHat/CentOS you have to wait even longer for the new
> release to include it again than is the case with Ubuntu LTS releases.
> 
> Kind Regards,
> 
> Bas
> 
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 [Regina Obe] 

-1 to making mandatory
I object too similar reasons as Bas.  I don't feel SFCGAL is stable enough to make it a required or even a default.

In the past SFCGAL has been broken sometimes and has taken a while for it to be rebuilt.
It's deep reliance on CGAL which itself doesn't seem to care about breaking people's stuff scares me.

In past on some platforms because it had that openscenegraph requirement for its gui, meant large hordes of dependencies had to be dragged in to support it.

The only unfortunate thing I see with it, is unlike raster which is a completely separate lib file, it is tangled in with the postgis lib when built.
I suspect we can't fix this that the whole backend switch thing requires it to be that way.  So that would make it much harder for packagers to have a version with and without SFCGAL.