ST_Union(geom[]) should unary union single entry arrays

References #5677
postgis · Feb 26, 2024 · bd10d04 · bd10d04
1 parent c90e282
commit bd10d04
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diff --git a/NEWS b/NEWS
@@ -3,6 +3,7 @@ PostGIS 3.2.8
 
 * Bug Fixes  *
 
+ - #5677, ST_Union(geom[]) should unary union single entry arrays (Paul Ramsey)
 
 
 PostGIS 3.2.7

diff --git a/postgis/lwgeom_geos.c b/postgis/lwgeom_geos.c
@@ -518,22 +518,29 @@ Datum pgis_union_geometry_array(PG_FUNCTION_ARGS)
 	if ( count == 0 )
 		PG_RETURN_NULL();
 
+	/* Ok, we really need GEOS now ;) */
+	initGEOS(lwpgnotice, lwgeom_geos_error);
+
 	/* One geom, good geom? Return it */
 	if ( count == 1 && nelems == 1 )
 	{
 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wsign-compare"
 #endif
-		PG_RETURN_POINTER((GSERIALIZED *)(ARR_DATA_PTR(array)));
+		g = POSTGIS2GEOS((GSERIALIZED *)(ARR_DATA_PTR(array)));
 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
 #pragma GCC diagnostic pop
 #endif
+		g_union = GEOSUnaryUnion(g);
+		GEOSGeom_destroy(g);
+		if (!g_union) HANDLE_GEOS_ERROR("GEOSUnaryUnion");
+		GEOSSetSRID(g_union, srid);
+		gser_out = GEOS2POSTGIS(g_union, is3d);
+		GEOSGeom_destroy(g_union);
+		PG_RETURN_POINTER(gser_out);
 	}
 
-	/* Ok, we really need GEOS now ;) */
-	initGEOS(lwpgnotice, lwgeom_geos_error);
-
 	/*
 	** Collect the non-empty inputs and stuff them into a GEOS collection
 	*/