[postgis-devel] liblwgeom symbols exported by postgis module

[Paragon Corporation]

strk,

I think Debian folks are most affected by this since they change our code to
dynamically link.  So I'm most concerned what they think

Do other package maintainers switch to dynamic linking postgis lib.

1) For things like the command line tools -- shp2gpsql, raster2pgsql and so
forth, I'm much less concerned about the name staying the same across
2.minor cause well we never versioned those anyway so they get overwritten
with each minor
And they don't change enough to be of much concern. Mostly bug fixes minor
enhancements.

2) For statically linking PostGIS 2.2, the whole thing becomes a non-issue
if we don't export symbols


Now there is one question I have for Sebastian and rest of Debian crew about
how they manage PostGIS distributions.  You say you only distribute one
version of PostGIS per PostgreSQL release.

Does this mean:

a) Since you shipped PostgreSQL 9.4 with PostGIS 2.1, you will never be
shipping PostGIS 2.2 for PostgreSQL 9.4?  
That would really suck since there would be no easy path to upgrade for
users.

or
b) Since you consider it a standard upgrade when PostGIS 2.2 comes out your
PostgreSQL 9.4 offering will then switch to PostGIS 2.2 and you'll uninstall
PostGIS 2.1?
This option would have me a bit concerned as it would mean peoples PostGIS
databases would be broken until they rush to do a 

ALTER EXTENSION postgis UPDATE;

On all of them -- so that would be a disclaimer we would need to flag.
The uninitiated user would be panick stricken - and worst yet if they had
just some sys admin with no PostgreSQL/PostGIS experience doing the standard
system upgrade all packages they could be down for hours.

or

c) Since you consider it a standard upgrade when PostGIS 2.2 comes out your
PostgreSQL 9.4 offering will then switch to PostGIS 2.2, but you'll keep
PostGIS 2.1 if installed?
- for selfish reasons I would prefer this (since it means we have more users
being able to use 2.2 (and can focus more attention on our newer offering)
though not necessarily the best solution for everyone
Since they could be running with an outdated 2.1 unless they are experienced
users.


Thanks,
Regina

-----Original Message-----
From: postgis-devel-bounces at lists.osgeo.org
[mailto:postgis-devel-bounces at lists.osgeo.org] On Behalf Of Sandro Santilli
Sent: Wednesday, September 30, 2015 3:34 PM
To: PostGIS Development Discussion <postgis-devel at lists.osgeo.org>;
Sebastiaan Couwenberg <sebastic at xs4all.nl>
Subject: Re: [postgis-devel] liblwgeom symbols exported by postgis module

So I've tried locally with mixing -release and -version-info so that we
produce (on Linux):

 liblwgeom-2.2.so.2.2.0
 liblwgeom-2.2.so.2 -> liblwgeom-2.2.so.2.2.0  liblwgeom.so ->
liblwgeom-2.2.so.2.2.0

With:

 Library soname: [liblwgeom-2.2.so.2]

How do you like that ?

I haven't access to BSD machines to see what would happen there.
Should I commit the change for broader testing ?

--strk;

On Wed, Sep 30, 2015 at 08:51:26PM +0200, Sandro Santilli wrote:
> On Wed, Sep 30, 2015 at 01:38:21PM -0400, Paragon Corporation wrote:
> 
> > So our liblwgeom versioning should ideally follow our minor 
> > versioning as I had originally asked for.
> 
> ...
> 
> > But normally liblwgeom-2.so would always be what you get with 2.2.x
> 
> With the current setup, liblwgeom.so.2 is what you get with any 2.x.x.
> Shall we break the application binary interface, for example by 
> changing the type of an argument (think BOX2D vs. GBOX which happened 
> with 2.0.0) then we'll have to encode that brokage by changing soname to
liblwgeom.so.3.
> 
> As long as changes are backward compatible there's no need to ever 
> change the SONAME. This worked for the C-API of GEOS since it was 
> introduced, with the single SONAME "libgeos_c.so.1" ever existed from
> GEOS-2.2.0 (2005) to GEOS-3.5.0 (2015).
> 
> That said, if we want to _pretend_ we break the ABI on every Minor 
> release (just so not to think about it) I guess we could do that, but 
> what would that buy us, exactly ?
> 
> --strk;
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