[postgis-devel] [PostGIS] #210: segmentation faults in lwgeom_geos.c:pgis_union_geometry_array

[PostGIS]

#210: segmentation faults in lwgeom_geos.c:pgis_union_geometry_array
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  Reporter:  dfuhriman  |       Owner:  robe         
      Type:  defect     |      Status:  assigned     
  Priority:  medium     |   Milestone:  postgis 1.3.7
 Component:  postgis    |     Version:  trunk        
Resolution:             |    Keywords:               
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Comment (by robe):

 Mark,

 I'm happy with this one for at least an RC.  I guess I misread your
 message thank goodness. I get same results for old as I did before and my
 all null make line no longer crashes.

 There is one example that is different from the old - and the error is not
 because of this patch, but of course because of the error checking we are
 doing.  I personally think both the 1.3 and the 1.4 answers are wrong in
 this case, but as to whether the 1.4 answer is wrong is debatable.

 If you call ST_MakeLine on a single point which could happen if you have a
 1 row table.

 In 1.3 -- you get a magical one pointed line:
 SELECT ST_AsText(ST_MakeLine(ST_GeomFromTExt('POINT(1 1)'))) ;

 LINESTRING(1 1)

 yes I thought it was very cool too. Many budding geometry Frankensteins
 will be unhappy they can no longer pull this off.

 In 1.4 you get
 ERROR:  geometry requires more points

 I personally think if you have one point in a make line -- it should just
 return NULL, but I'm not strongly feeling about this except for the fact
 it will break code in cases where only one record has been put in.

 Cool I can still create a line with identical points which is same
 behavior as 1.3.

 SELECT ST_IsValid(ST_MakeLine(the_geom))
 FROM (VALUES (ST_GeomFromTExt('POINT(1 1)')), (ST_GeomFromTExt('POINT(1
 1)') ) ) As foo(the_geom) ;

 I think this patch may be a winner so go ahead and commit it if Paul is
 okay.

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/210#comment:35>
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