VoronoiLines hangs indefinitely on multipoint

[robe]

I tested on 3.8.0 (still have to test on 3.8.1) but definitely an issue on GEOS head.

SELECT ST_VoronoiLines('MULTIPOINT(-10 40,5 40,20 40,35 40,50 40,-10 55,5 55,20 55,35 55,50 55,-10 70,5 70,20 70,35 70,50 70)'::geometry, 20.1, 'POINT(-11.1111111 40)'::geometry)

See related PostGIS ticket

​https://trac.osgeo.org/postgis/ticket/4726

Raul's trace

#0  0x00007fc3eacf126c in geos::triangulate::quadedge::Vertex::isCCW (this=<optimized out>, b=..., c=...) at ../../../include/geos/triangulate/quadedge/Vertex.h:226
#1  geos::triangulate::quadedge::Vertex::rightOf (this=0x55bba48b9720, e=...) at Vertex.cpp:83
#2  0x00007fc3eace807c in geos::triangulate::IncrementalDelaunayTriangulator::insertSite (this=<optimized out>, v=...) at IncrementalDelaunayTriangulator.cpp:90
#3  0x00007fc3eace7e4b in geos::triangulate::IncrementalDelaunayTriangulator::insertSites (this=0x7ffe3cf96408, vertices=...) at IncrementalDelaunayTriangulator.cpp:40
#4  0x00007fc3eace9f5d in geos::triangulate::VoronoiDiagramBuilder::create (this=0x7ffe3cf964b8) at VoronoiDiagramBuilder.cpp:93
#5  0x00007fc3eacea45b in geos::triangulate::VoronoiDiagramBuilder::getDiagramEdges (this=0x7ffe3cf964b8, geomFact=...) at VoronoiDiagramBuilder.cpp:122
#6  0x00007fc3eba9c83e in GEOSVoronoiDiagram_r::$_188::operator() (this=<optimized out>) at geos_ts_c.cpp:3261
#7  execute<GEOSVoronoiDiagram_r::$_188, (decltype(nullptr))0>(GEOSContextHandle_HS*, GEOSVoronoiDiagram_r::$_188&&) (extHandle=0x55bba48b88b0, f=...) at geos_ts_c.cpp:379
#8  GEOSVoronoiDiagram_r (extHandle=0x55bba48b88b0, g1=0x55bba48b6840, env=0x55bba48e6f40, tolerance=20.100000000000001, onlyEdges=1) at geos_ts_c.cpp:3253
#9  0x00007fc3ebc02ecb in lwgeom_voronoi_diagram (g=<optimized out>, env=0x7ffe3cf965c0, tolerance=20.100000000000001, output_edges=-1534355264) at lwgeom_geos.c:1926
#10 0x00007fc3ebb3267e in ST_Voronoi (fcinfo=0x55bba48fbb20) at lwgeom_geos.c:3465
#11 0x000055bba3c126e1 in ExecInterpExpr (state=<optimized out>, econtext=<optimized out>, isnull=0x7ffe3cf9675f) at execExprInterp.c:625
#12 0x000055bba3c45874 in ExecEvalExprSwitchContext (state=0x55bba48fba48, econtext=0x55bba48fb770, isNull=0x7ffe3cf9675f) at ../../../src/include/executor/executor.h:307
[...]

(gdb) c
Continuing.
^C
Program received signal SIGINT, Interrupt.
geos::triangulate::quadedge::Vertex::isCCW (this=<optimized out>, b=..., c=...) at ../../../include/geos/triangulate/quadedge/Vertex.h:227
227                    > (b.p.y - p.y) * (c.p.x - p.x);
(gdb) bt
#0  geos::triangulate::quadedge::Vertex::isCCW (this=<optimized out>, b=..., c=...) at ../../../include/geos/triangulate/quadedge/Vertex.h:227
#1  geos::triangulate::quadedge::Vertex::rightOf (this=0x55bba48b9ee0, e=...) at Vertex.cpp:83
#2  0x00007fc3eace807c in geos::triangulate::IncrementalDelaunayTriangulator::insertSite (this=<optimized out>, v=...) at IncrementalDelaunayTriangulator.cpp:90
#3  0x00007fc3eace7e4b in geos::triangulate::IncrementalDelaunayTriangulator::insertSites (this=0x7ffe3cf96408, vertices=...) at IncrementalDelaunayTriangulator.cpp:40
#4  0x00007fc3eace9f5d in geos::triangulate::VoronoiDiagramBuilder::create (this=0x7ffe3cf964b8) at VoronoiDiagramBuilder.cpp:93
#5  0x00007fc3eacea45b in geos::triangulate::VoronoiDiagramBuilder::getDiagramEdges (this=0x7ffe3cf964b8, geomFact=...) at VoronoiDiagramBuilder.cpp:122
#6  0x00007fc3eba9c83e in GEOSVoronoiDiagram_r::$_188::operator() (this=<optimized out>) at geos_ts_c.cpp:3261
#7  execute<GEOSVoronoiDiagram_r::$_188, (decltype(nullptr))0>(GEOSContextHandle_HS*, GEOSVoronoiDiagram_r::$_188&&) (extHandle=0x55bba48b88b0, f=...) at geos_ts_c.cpp:379
#8  GEOSVoronoiDiagram_r (extHandle=0x55bba48b88b0, g1=0x55bba48b6840, env=0x55bba48e6f40, tolerance=20.100000000000001, onlyEdges=1) at geos_ts_c.cpp:3253
#9  0x00007fc3ebc02ecb in lwgeom_voronoi_diagram (g=<optimized out>, env=0x7ffe3cf965c0, tolerance=20.100000000000001, output_edges=-1534355264) at lwgeom_geos.c:1926
#10 0x00007fc3ebb3267e in ST_Voronoi (fcinfo=0x55bba48fbb20) at lwgeom_geos.c:3465
[...]