Added comment about the use of postgis_lib_version in version checker

(last commit log was incomplete)

git-svn-id: http://svn.osgeo.org/postgis/trunk@2212 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/utils/postgis_proc_upgrade.pl b/utils/postgis_proc_upgrade.pl
index 43509e92cd6f5b76d5f0953eab4ff889bb002559..59b3881f97fc62a31eff5bbc31dea9d3d8ad8301 100755 (executable)
--- a/utils/postgis_proc_upgrade.pl
+++ b/utils/postgis_proc_upgrade.pl
@@ -100,6 +100,18 @@ DECLARE
        old_majmin text;
        new_majmin text;
 BEGIN
+       --
+       -- This uses postgis_lib_version() rather then
+       -- postgis_scripts_installed() as in 1.0 because
+       -- in the 1.0 => 1.1 transition that would result
+       -- in an impossible upgrade:
+       --
+       --   from 0.3.0 to 1.1.0
+       --
+       -- Next releases will still be ok as
+       -- postgis_lib_version() and postgis_scripts_installed()
+       -- would both return actual PostGIS release number.
+       -- 
        SELECT into old_scripts postgis_lib_version();
        SELECT into new_scripts ''NEWVERSION'';
        SELECT into old_majmin substring(old_scripts from 1 for 4);