[postgis-tickets] [PostGIS] #3464: ERROR: lwt_ChangeEdgeGeom could not construct face X, on the left of edge Y

[PostGIS]

#3464: ERROR: lwt_ChangeEdgeGeom could not construct face X, on the left of edge Y
-----------------------+----------------------------
  Reporter:  strk      |      Owner:  strk
      Type:  defect    |     Status:  new
  Priority:  medium    |  Milestone:  PostGIS Future
 Component:  topology  |    Version:  trunk
Resolution:            |   Keywords:  robustness
-----------------------+----------------------------

Comment (by strk):

 So with r14690 I added the "side-location conflict" check, although with
 different wording:
 {{{
 psql:bug3464.sql:21: ERROR:  corrupted topology: new edge starts in face 1
 and ends in face 0
 }}}

 The message, as usual, doesn't really contain enough info to know what's
 going on, but the point is that the topology is found to be corrupted
 because the edge-adding function first checks for edge/edge crossing and
 finds none, but then finds that the edge started in a face and ended in
 another, according to topology metadata.

 Now I suspect the edge-crossing check is giving a false negative here,
 because the topology isn't really invalid, but rather that component line
 is crossing (almost in parallel) an existing topology edge.

 As the edge-crossing check uses Relate, there might be a bug in GEOS
 Relate, not finding a puntual intersection.

--
Ticket URL: <https://trac.osgeo.org/postgis/ticket/3464#comment:14>
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