[PostGIS] #5612: Regression failure with CG_Visibility

[PostGIS]

#5612: Regression failure with CG_Visibility
--------------------+---------------------------
 Reporter:  robe    |      Owner:  lbartoletti
     Type:  defect  |     Status:  new
 Priority:  medium  |  Milestone:  PostGIS 3.5.0
Component:  sfcgal  |    Version:  master
 Keywords:          |
--------------------+---------------------------
 This is only relevant for systems running SFCGAL 1.5.0+ and related to
 commit of https://git.osgeo.org/gitea/postgis/postgis/pulls/156

 On GHA all the runners running SFCGAL master and CGAL 4.6 are failing
 regression


 {{{
  Visibility point in polygon|POLYGON((3 2,1 2,0 4,0 0,3 2))
  Visibility point in polygon with hole|POLYGON((0 1.67,0.2 1.8,0.9
 1.8,1.93 1.29,3 2,1 2,0 4,0 1.67))
 -Visibility segment in polygon|POLYGON((1 2,0 4,0 0,4 0,4 4,1 2))
 +Visibility segment in polygon|POLYGON((1 2,0 4,1 0,4 4,4 0,4 4,1 2))
  Visibility segment in polygon with hole|POLYGON((19 -2,12 6,14 14,10.43
 7.57,11 7,11 6,10 6,9.56 6,9 5,1 2,4.67 2.33,8 4,10 3,9.87 2.81,12 3,19
 -2))
 }}}


 On winnie, I don't know if a fluke or what, but PG16 is passing fine
 https://winnie.postgis.net/job/PostGIS_EDB_Regress_winnie/17940/consoleFull
 , and it's running SFCGAL 1.5.0 released, CGAL 4.6 released

 the PG15 is running the exact same copy of the SFCGAL/CGAL (they are
 pointing at the same files), but the PG15 run is failing with same issue
 as the GHAs that are running against master SFCGAL

 https://winnie.postgis.net/job/PostGIS_EDB_Regress_winnie/17941/consoleFull
 {{{
  ./sfcgal/regress/visibility .. failed (diff expected obtained:
 /projects/postgis/tmp/3.5.0dev_pg15_geos3.13_gdal3.7.1w64/test_172_diff)
 -----------------------------------------------------------------------------
 --- ./sfcgal/regress/visibility_expected        2023-11-15
 01:06:51.527511000 -0500
 +++ /projects/postgis/tmp/3.5.0dev_pg15_geos3.13_gdal3.7.1w64/test_172_out
 2023-11-15 14:13:33.448220200 -0500
 @@ -1,4 +1,4 @@
  Visibility point in polygon|POLYGON((3 2,1 2,0 4,0 0,3 2))
  Visibility point in polygon with hole|POLYGON((0 1.67,0.2 1.8,0.9
 1.8,1.93 1.29,3 2,1 2,0 4,0 1.67))
 -Visibility segment in polygon|POLYGON((1 2,0 4,0 0,4 0,4 4,1 2))
 +Visibility segment in polygon|POLYGON((1 2,4 4,4 0,4 4,4 0,0 4,1 2))
  Visibility segment in polygon with hole|POLYGON((19 -2,12 6,14 14,10.43
 7.57,11 7,11 6,10 6,9.56 6,9 5,1 2,4.67 2.33,8 4,10 3,9.87 2.81,12 3,19
 -2))
 -----------------------------------------------------------------------------
 }}}

 The polygons are definitely different.
-- 
Ticket URL: <https://trac.osgeo.org/postgis/ticket/5612>
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