[postgis-devel] PSC Vote: Drop the minor in the postgis lib files

[Regina Obe]

As mentioned before, though I forget if I got enough consensus to move
forward.

I would like the minor of our lib file dropped in 3.0

So that would mean 

1) The installed lib file would be called  postgis-3 for 3.0, 3.1, 3.2  etc.
rtpostgis-3, postgis_topology-3 etc.
2) The extension version would still contain the minor and micro as it
always has
3) We would have a special switch in the .configure (by default turned off),
for development purposes called:

--add-lib-minor  (that's my current favorite, though I'm open to changing
the name)

This is mostly a development switch so developers can test say 3.0, 3.1 in
the same postgres instance (different databases) or for those folks who want
to run both and compile their own postgis.


-- What this solves

1) Much smoother pg_upgrade for users.  Right now whenever anyone needs to
use pg_upgrade, they need to install  an older postgis in their newer
install or use a hack to symlink the old name to the new name
2) By dropping the Minor, this pain goes away, and also means we don't need
to always support newer versions of PostgreSQL on older versions of PostGIS
as long as we release before the PostgreSQL version.


-- What we give up
1) We need to be very careful not to remove C functions exposed in SQL
scripts that are referenced in older versions of the same major.  So that
means 3.1 can't remove any C - SQL API exposed functions we introduced in
3.0, though it can add more.
  If we need remove said functions, we need to stub those functions with an
error code but keep the signature.

The reason why this is necessary is that during pg_upgrade, the upgrade
script recreates the extension from what was already installed by installing
each function, so if during install, it hits a function that can't find it's
C-function mate, upgrade will fail.

Note helper functions we have that just get called internally by our other
functions we can rename all we like.


+1 to push forward (after all the bots are happy again).



Thanks,
Regina