[postgis-tickets] [PostGIS] #5401: ST_Difference silently giving us wrong results

[PostGIS]

#5401: ST_Difference silently giving us wrong results
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  Reporter:  laopsahl  |      Owner:  pramsey
      Type:  defect    |     Status:  new
  Priority:  medium    |  Milestone:  PostGIS 3.3.4
 Component:  postgis   |    Version:  3.3.x
Resolution:            |   Keywords:
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Comment (by strk):

 The referenced data is in these files:
    - https://gitlab.com/nibioopensource/resolve-overlap-and-
 gap/-/blob/develop/src/test/sql/regress/data/all_area.sql
    - https://gitlab.com/nibioopensource/resolve-overlap-and-
 gap/-/blob/develop/src/test/sql/regress/data/used_area.sql

 The query runs a difference between the UNION of used area polygons and
 the COLLECTION of all area polygons. This is technically an unsupported
 overlay operation as it involves collections. The fact it works is
 accidental and currently under discussion here:
 https://github.com/libgeos/geos/issues/797

 That said, the result on my system is acceptable. I'm running:

 POSTGIS="3.4.0dev 3.3.0rc2-960-g8b6d264b9"
 GEOS="3.12.0dev-CAPI-1.18.0"
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Ticket URL: <https://trac.osgeo.org/postgis/ticket/5401#comment:4>
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