[postgis-devel] About EXTENSION from UNPACKAGED on PostgreSQL 13

[Sandro Santilli]

On Wed, Feb 26, 2020 at 08:55:03AM -0500, Stephen Frost wrote:
> Greetings,
> 
> * Darafei "Komяpa" Praliaskouski (me at komzpa.net) wrote:
> > PostGIS 2.5 had raster and vector blended together in single extension.
> > In PostGIS 3, they were split out into postgis and postgis_raster extensions.
> 
> For my 2c, at least, I still don't really get why that split was done.

It's pretty easy to understand: to let user decide what he needs and
what not.

> > Removal of FROM UNPACKAGED breaks PostGIS 2.5 -> 3.0 upgrade path, and
> > we haven't yet found a proper replacement since such removal wasn't
> > something we were expecting.
> 
> I agree that there probably isn't a very good path to allow an extension
> to be split up like that without having to drop some things.  An
> alternative would have been to *not* split up postgis, but rather to
> have a postgis_raster and a postgis_vector.  Adding in support for other
> ways to migrate a function from one extension to another would make
> sense too.

I think support for migrating an object between extensions DOES exist,
it's just that you cannot use it from extension upgrade scripts.

Anyway pgsql-hackers is not the right place for discussion.
On pgsql-hackers we only want to find a future-proof way to "package
existing objects into an extension".  If the syntax
`CREATE EXTENSION <extname> FROM UNPACKAGED` 
has gone, would it be ok for just:
`CREATE EXTENSION <extname>`
to intercept unpackaged objects and package them ?

--strk;