Fix expression-based ST_MapAlgebra resulting in regression failures on some machines

git-svn-id: http://svn.osgeo.org/postgis/trunk@11277 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/raster/rt_pg/rt_pg.c b/raster/rt_pg/rt_pg.c
index 762907546ee1d1d02c698a92cc5c075ba2585a60..b2204205d597e9e69c98db4f60d2e7a656c726ba 100644 (file)
--- a/raster/rt_pg/rt_pg.c
+++ b/raster/rt_pg/rt_pg.c
@@ -15348,7 +15348,7 @@ static int rtpg_nmapalgebra_rastbandarg_process(rtpg_nmapalgebra_arg arg, ArrayT
 
                /* see if this is a copy of an existing pgraster */
                for (j = 0; j < i; j++) {
-                       if (arg->pgraster[i] == arg->pgraster[j]) {
+                       if (!arg->isempty[j] && (arg->pgraster[i] == arg->pgraster[j])) {
                                POSTGIS_RT_DEBUG(4, "raster matching existing same raster found");
                                arg->raster[i] = arg->raster[j];
                                arg->ownsdata[i] = 0;