Handle ordinates for empty IGeometryCollection (npgsql#2258)

austindrenski · web-flow · commit 3fa2162ef32b · 2018-12-10T00:14:04.000-05:00
See: npgsql/efcore.pg/pull/732
diff --git a/src/Npgsql.NetTopologySuite/NpgsqlPostGisWriter.cs b/src/Npgsql.NetTopologySuite/NpgsqlPostGisWriter.cs
@@ -508,8 +508,8 @@ private static Ordinates CheckOrdinates(IGeometry geometry)
                 return CheckOrdinates(((ILineString)geometry).CoordinateSequence);
             if (geometry is IPolygon)
                 return CheckOrdinates((((IPolygon)geometry).ExteriorRing).CoordinateSequence);
-            if (geometry is IGeometryCollection)
-                return CheckOrdinates(geometry.GetGeometryN(0));
+            if (geometry is IGeometryCollection collection)
+                return collection.Count == 0 ? Ordinates.None : CheckOrdinates(collection.GetGeometryN(0));
 
             Assert.ShouldNeverReachHere();
             return Ordinates.None;
diff --git a/test/Npgsql.PluginTests/NetTopologySuiteTests.cs b/test/Npgsql.PluginTests/NetTopologySuiteTests.cs
@@ -149,6 +149,12 @@ public static IEnumerable TestCases {
                     "st_multi(st_makepolygon(st_makeline(ARRAY[st_makepoint(1,1),st_makepoint(2,2),st_makepoint(3,3),st_makepoint(1,1)])))"
                 );
 
+                yield return new TestCaseData(
+                    Ordinates.None,
+                    GeometryCollection.Empty,
+                    "st_geomfromtext('GEOMETRYCOLLECTION EMPTY')"
+                );
+
                 yield return new TestCaseData(
                     Ordinates.None,
                     new GeometryCollection(new IGeometry[]
