[PostGIS] #5947: Crash in ST_ModEdgeHeal

[PostGIS]

#5947: Crash in ST_ModEdgeHeal
----------------------+---------------------------
 Reporter:  strk      |      Owner:  strk
     Type:  defect    |     Status:  new
 Priority:  blocker   |  Milestone:  PostGIS 3.5.4
Component:  topology  |    Version:  3.5.x
 Keywords:  garden    |
----------------------+---------------------------
 From garden test (make garden):

 {{{
 (gdb) bt
 #0  0x0000556a68009d8a in repalloc ()
 #1  0x00007fd5a890b6d7 in ptarray_append_ptarray
 (pa1=pa1 at entry=0x556a7b7737f8, pa2=0x556a7b773a58,
 gap_tolerance=gap_tolerance at entry=0) at ptarray.c:235
 #2  0x00007fd5a8946d15 in _lwt_HealEdges (topo=topo at entry=0x556a7b7732e8,
 eid1=eid1 at entry=22, eid2=eid2 at entry=163, modEdge=modEdge at entry=1) at
 topo/lwgeom_topo.c:4643
 #3  0x00007fd5a894a51a in lwt_ModEdgeHeal (topo=topo at entry=0x556a7b7732e8,
 e1=e1 at entry=22, e2=e2 at entry=163) at topo/lwgeom_topo.c:4822
 #4  0x00007fd5a8908d84 in ST_ModEdgeHeal (fcinfo=0x556a7b8f84a8) at
 postgis_topology.c:4704
 }}}

 The "offending query" is:
 {{{
 SELECT RemoveUnusedPrimitives('topo_test');
 }}}

 Topology contains a lot of EMPTY edges (which should probably not be
 allowed)
-- 
Ticket URL: <https://trac.osgeo.org/postgis/ticket/5947>
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