[PostGIS] #5782: TopoGeo_addLinestring corrups topology: adjacent edges 33 and -32 bind different face (1 and 0)

[PostGIS]

#5782: TopoGeo_addLinestring corrups topology: adjacent edges 33 and -32 bind
different face (1 and 0)
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  Reporter:  Lars Aksel Opsahl  |      Owner:  strk
      Type:  defect             |     Status:  new
  Priority:  high               |  Milestone:  PostGIS 3.4.4
 Component:  topology           |    Version:
Resolution:                     |   Keywords:
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Comment (by strk):

 What I can tell is that GEOS finds the correct edge being closer.
 Here's a simple test:

 {{{
 A='LINESTRING(18.00678831099686 69.0404811833497,18.006784630996860
 69.04045431334970,18.00677727099686 69.0404005833497)'
 B='LINESTRING(18.00677727099686 69.0404005833497,18.006780950996863
 69.04042744334969,18.00678831099686 69.0404811833497)'
 Q='POINT(18.006691126034692 69.04048768506776)'

 AQ_geos=$(geosop -a "$A" -b "$Q" distance)
 AQ_pgis=$(psql -XtAc "SELECT ST_Distance('$A', '$Q')")
 BQ_geos=$(geosop -a "$B" -b "$Q" distance)
 BQ_pgis=$(psql -XtAc "SELECT ST_Distance('$B', '$Q')")

 echo "PostGIS:"
 echo " A-Q: $AQ_pgis"
 echo " B-Q: $BQ_pgis"

 echo "GEOS:"
 echo " A-Q: $AQ_geos"
 echo " B-Q: $BQ_geos"
 }}}

 The results I get:
 {{{
 PostGIS:
  A-Q: 9.716835623285099e-05
  B-Q: 9.716835623092273e-05
 GEOS:
  A-Q: 9.7168356230588148e-05
  B-Q: 9.7168356230827946e-05
 }}}

 Basically PostGIS finds B being closer to Q while GEOS finds A being
 closer to Q.
 In our case the GEOS answer would be more appropriate.

 What we are using to find the closest edge is the `<->` operator.
-- 
Ticket URL: <https://trac.osgeo.org/postgis/ticket/5782#comment:18>
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