[PostGIS] #6064: Silent topology corruption with topology.ST_AddEdgeModFace (was: Silent topology corruption with topology.TopoGeo_addLinestring)

[PostGIS]

#6064: Silent topology corruption with topology.ST_AddEdgeModFace
-----------------------+--------------------
  Reporter:  strk      |      Owner:  strk
      Type:  defect    |     Status:  new
  Priority:  medium    |  Milestone:
 Component:  topology  |    Version:  master
Resolution:            |   Keywords:
-----------------------+--------------------
Changes (by strk):

 * summary:  Silent topology corruption with topology.TopoGeo_addLinestring
     => Silent topology corruption with topology.ST_AddEdgeModFace


Old description:

> As of commit [67ff872e2d4b8b46e6d412dae592e89480fc668c/git] a topology
> can be corrupted without exception by using TopoGeo_addLinestring.
>
> Test attached.
>
> This is a spin-off of #6062
>
> Full version:
> {{{
> POSTGIS="3.7.0dev 3.6.0rc2-417-g67ff872e2" [EXTENSION] PGSQL="180"
> GEOS="3.14.2dev-CAPI-1.20.5" PROJ="9.6.0 NETWORK_ENABLED=OFF
> URL_ENDPOINT=https://cdn.proj.org USER_WRITABLE_DIRECTORY=/tmp/proj
> DATABASE_PATH=/usr/share/proj/proj.db" (compiled against PROJ 9.6.0)
> LIBXML="2.9.14" LIBJSON="0.18" LIBPROTOBUF="1.5.1" WAGYU="0.5.0
> (Internal)" TOPOLOGY
> }}}

New description:

 As of commit [67ff872e2d4b8b46e6d412dae592e89480fc668c/git] a topology can
 be corrupted without exception by using ST_AddEdgeModFace.

 Test attached.

 This is a spin-off of #6062

 Full version:
 {{{
 POSTGIS="3.7.0dev 3.6.0rc2-417-g67ff872e2" [EXTENSION] PGSQL="180"
 GEOS="3.14.2dev-CAPI-1.20.5" PROJ="9.6.0 NETWORK_ENABLED=OFF
 URL_ENDPOINT=https://cdn.proj.org USER_WRITABLE_DIRECTORY=/tmp/proj
 DATABASE_PATH=/usr/share/proj/proj.db" (compiled against PROJ 9.6.0)
 LIBXML="2.9.14" LIBJSON="0.18" LIBPROTOBUF="1.5.1" WAGYU="0.5.0
 (Internal)" TOPOLOGY
 }}}

--
Comment:

 Further simplification of the test, completely removing the code that
 takes care of noding. This one ONLY uses `ST_AddEdgeModFace`:
 {{{
 SELECT NULL FROM topology.CreateTopology ('t6064');

 SELECT topology.ST_AddIsoNode('t6064', 0, 'POINT(17.42207545158684
 69.11091383590066)'); -- n1
 SELECT topology.ST_AddIsoNode('t6064', 0, 'POINT(17.622976580401446
 69.12848944101118)'); -- n2
 SELECT topology.ST_AddIsoNode('t6064', 0, 'POINT(17.42207545158653
 69.11091383590062)'); -- n3

 SELECT 't6064.1', count(*) FROM topology.ST_AddEdgeModFace('t6064',
 1, 2,
 'LINESTRING(
   17.42207545158684 69.11091383590066,
   17.422075702665087 69.11091383235977,
   17.579930758184094 69.12294910230447,
   17.622976580401446 69.12848944101118
 )');


 SELECT 't6064.2', count(*) FROM topology.ST_AddEdgeModFace('t6064',
 3,1,
 'LINESTRING(
   17.42207545158653 69.11091383590062,
   17.42207545158684 69.11091383590066
 )');
 -- valid thus far

 -- Silently corrupts topology, updating edge 1 side faces as it thinks
 -- left side is a new face (it isn't).
 -- The code finds rings on BOTH sides of this new edge to be
 counterclockwise
 -- but instead only one side of them is.
 --
 -- This is likely due to the presence of very long dangling edges.
 --
 SELECT 't6064.3', count(*) FROM topology.ST_AddEdgeModFace('t6064',
 1, 3,
 'LINESTRING(
   17.42207545158684 69.11091383590066,
   17.42207570266477 69.11091383235974,
   17.42207545158653 69.11091383590062
 )'
 );
 }}}
-- 
Ticket URL: <https://trac.osgeo.org/postgis/ticket/6064#comment:7>
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