[postgis-devel] Versioning and Branching Rationale

[strk at refractions.net]

After a long session with our excellent System Architect we
finally have a *simple* versioning scheme (thanks, Paul).

Versions unification
--------------------

PostGIS core has a SINGLE version.
No more SCRIPTS version.

Upgrades 
--------

Upgrades between MINOR.MICRO releases only require
sourcing the `lwpostgis_upgrade.sql' script:

	psql -f lwpostgis_upgrade.sql <spatial_db>

Upgrades between MAJOR releases require dump/reload
as described in the HARD UPGRADE section of the manual.

Parallel installations
----------------------

Parallel MAJOR PostGIS release installations are
supported on *all* architectures.

Parallel MINOR PostGIS release installations are
NOT supported (altought technically possible on
most archs).

Version printing functions
--------------------------

PostGIS version returned by sql functions
always refer to the unified version numbers.

This includes:
	postgis_version()
	postgis_full_version()
	postgis_lib_version()
	postgis_scripts_released()
	postgis_scripts_installed()

The postgis_scripts_installed() is a procedural
function, with version hard-coded in its body.
This allows checking of lib/scripts matching.
The check is performed automatically by
postgis_full_version() warning you in case you
forgot to upgrade an existing spatial db.

The postgis_lib_version() and postgis_scripts_released()
functions will return the same value.

The postgis_version() function will retain its format
for backward compatibility. This means that MICRO
version will NOT be shown.


Branching
---------

CVS branches will only be defined for MAJOR releases.
Branches between MINOR.MICRO releases will be avoided.
As a consequence the 1.0 branch is abandoned and 1.0.x
installations will not be considered in any special way.

Currently supported branches are: 0.x and 1.0.
For historical reasons these are respectively tagged
as: pgis_0_9_0 and HEAD.


--strk;

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