[postgis-devel] Upgrade paths (again)

[Sandro Santilli]

On Thu, Sep 15, 2022 at 11:32:02AM +0800, Julien Rouhaud wrote:

> This problem would also exit
> today if any change to postgis_extensions_upgrade() is needed, but I'm assuming
> that the odds to need a change there are hopefully very low.

In the various versions of postgis_extensions_upgrade() we have
had the following expectances:

  Existance of <cur>--<cur>next and <cur>next--<cur> paths
   (only needed to upgrade to same Major.Minor.Micro versions)

  Existance of ANY--<cur> path
   (used to upgrade from any previous versions)

The change I'm proposing in the "upgrade-paths" branch keeps
the ANY--<cur> path thus still works with old releases.

The change I'm proposing drastically reduces the amount of files
possibly installed on people machines, becuase the *SAME* set of
"upgrade-from-old-version" files would be contained by each and
every future release of PostGIS, that is:

  <old>--ANY

So instead of having:

  <old>--v1
  <old>--v2
  <old>--v3

For each version you ever installed on your system (I do understand
this is only happening on developers machines, not machines using
packages), you'd have a single one.

Separately, I'm working on an upstream patch that would allow us to
ONLY ever install a single upgrade path for each new version of PostGIS:

  %--<cur>

See https://commitfest.postgresql.org/38/3654/

--strk;