[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:  Lars Aksel Opsahl  |      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):

 Just to complete the picture, the debugging logs continue to the precision
 reduction heuristics which end up with the garbage result. Detailed logs
 are in https://github.com/libgeos/geos/issues/924#issuecomment-1593160531

 It turns out this problem is 2-fold:

  1. GEOMETRYCOLLECTION should not be passed to ST_Difference but GEOS
 fails to report this ---> https://github.com/libgeos/geos/issues/925
  2. GEOS attempts to still support the operation goes too far --->
 https://github.com/libgeos/geos/issues/924
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Ticket URL: <https://trac.osgeo.org/postgis/ticket/5401#comment:17>
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