ST_IsValidDetail and ST_IsValidReason POLYGON CRASH

[robe]

SELECT ST_IsValidDetail(ST_GeomFromText('POLYGON EMPTY',4326)) CRASH:

Again other empties don't seem to crash: e.g. SELECT ST_IsValidDetail(ST_GeomFromText('MULTIPOLYGON EMPTY',4326));

returns: (t₎

SELECT ST_IsValidDetail(ST_GeomFromText('LINESTRING EMPTY',4326)); returns (t₎

some return not supported.

[robe]

SELECT ST_IsValidReason(ST_GeomFromText('POLYGON EMPTY',4326)) also crashes.

{{{ --this works as long as you don't introduce POLYGON EMPTY SELECT ST_IsValidReason(geom), ST_IsValidDetail(geom) FROM (SELECT ST_GeomFromText('POINT EMPTY',4326)

UNION ALL SELECT ST_GeomFromText('MULTIPOINT EMPTY',4326) UNION ALL SELECT ST_GeomFromText('MULTIPOLYGON EMPTY',4326) UNION ALL SELECT ST_GeomFromText('LINESTRING EMPTY',4326)

UNION ALL SELECT ST_GeomFromText('MULTILINESTRING EMPTY',4326) )

As foo(geom);

}}}

[robe]

sorry formatting got messed up -- this crashes SELECT ST_IsValidReason(ST_GeomFromText('POLYGON EMPTY',4326));

--this works as long as you don't introduce POLYGON EMPTY

  SELECT ST_IsValidReason(geom), ST_IsValidDetail(geom) FROM (SELECT ST_GeomFromText('POINT EMPTY',4326)

    UNION ALL SELECT ST_GeomFromText('MULTIPOINT EMPTY',4326) UNION ALL SELECT ST_GeomFromText('MULTIPOLYGON EMPTY',4326) UNION ALL SELECT ST_GeomFromText('LINESTRING EMPTY',4326)

    UNION ALL SELECT ST_GeomFromText('MULTILINESTRING EMPTY',4326) )

    As foo(geom);

[pramsey]

It looks pretty easy if one knows what the form of a GEOS empty polygon is. In the case of LWGEOM, it's coming in with nrings == 0 and rings == NULL, so it crashes when it tries to dereference rings[0]. Instead of de-referencing it should be checking for nrings == 0 and in that case constructing an empty polygon.

It looks like both the LINESTRING and POINT cases work because they are going in with a non-null POINTARRAY that has npoints == 0 and *serialized_ptlist == NULL. So the GEOS interpretation of "empty" is working in those cases. Any help you can provide, appreciated.

For GEOS 3.3 you've provided nice easy createEmpty signatures, but what happened for pre-3.3? We did pass in empty geometry collections, right? I've got GEOS 3.2 and it's handling every other empty just fine.

[pramsey]

Fixed in trunk at r7491. See also #1065.