[PostGIS] #5899: pg_upgrade fails restore geography because spatial_ref_sys does not exist

[PostGIS]

#5899: pg_upgrade fails restore geography because spatial_ref_sys does not exist
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  Reporter:  robe     |      Owner:  pramsey
      Type:  defect   |     Status:  new
  Priority:  medium   |  Milestone:  PostGIS 3.2.9
 Component:  postgis  |    Version:  3.4.x
Resolution:           |   Keywords:
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Comment (by robe):

 I think the failure is happening here -

 https://git.osgeo.org/gitea/postgis/postgis/src/branch/master/postgis/gserialized_typmod.c#L344
 call to srid_check_latlong

 I'm thinking some of these possible solutions:

 1) Any spatial_ref_sys check should confirm the table exists and is not
 empty otherwise just return success with a warning.  This would also take
 care of those situations where people are using ST_Transform on their
 indexes or have check constraints checking spatial_ref_sys and pg_upgrade
 doesn't create spatial_ref_sys or populate spatial_ref_sys before trying
 to load user data.

 2) Change srid_check_latlong, to hard-code some common known long lats (or
 read from proj.db) and check against that before resorting to reading
 spatial ref sys.
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Ticket URL: <https://trac.osgeo.org/postgis/ticket/5899#comment:1>
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