Fix overlay op regression with mixed GeometryCollection on 3.9 branch (…

…#1050)

* Fix overlay op regression with mixed GeometryCollection on 3.9 branch
* Test overlay op with mixed GeometryCollection

NEWS

@@ -18,6 +18,7 @@ xxxx-xx-xx
   - Remove undefined behaviour in use of null PrecisionModel (GH-931, Jeff Walton)
   - Skip over testing empty distances for mixed collections (GH-979, Paul Ramsey)
   - Add missing cstdint headers (GH-990, GH-743, Regina Obe, Sergei Trofimovich)
+  - HeuristicOverlay: Fix overlay op regression (GH-1050, Mike Taves)
 
 
 ## Changes in 3.9.4

src/geom/HeuristicOverlay.cpp

@@ -421,7 +421,8 @@ HeuristicOverlay(const Geometry* g0, const Geometry* g1, int opCode)
 
         return ret;
     }
-    catch(const geos::util::TopologyException& ex) {
+    catch(const geos::util::IllegalArgumentException& ex) {
+        // Mixed GeometryCollection; see GH-1050
         ::geos::ignore_unused_variable_warning(ex);
 
 #if GEOS_DEBUG_HEURISTICOVERLAY

tests/unit/capi/GEOSDifferenceTest.cpp

@@ -40,5 +40,33 @@ void object::test<1>()
     GEOSGeom_destroy(result);
 }
 
+/**
+* Mixed GeometryCollection types permitted at a high-level
+*/
+template<>
+template<>
+void object::test<2>()
+{
+    GEOSGeometry* a = GEOSGeomFromWKT("GEOMETRYCOLLECTION (POINT (51 -1), LINESTRING (52 -1, 49 2))");
+    GEOSGeometry* b = GEOSGeomFromWKT("POINT (2 3)");
+
+    ensure(a);
+    ensure(b);
+
+    GEOSGeometry* ab = GEOSDifference(a, b);
+    GEOSGeometry* ba = GEOSDifference(b, a);
+
+    ensure(ab);
+    ensure(ba);
+
+    ensure_geometry_equals(ab, a);
+    ensure_geometry_equals(ba, b);
+
+    GEOSGeom_destroy(a);
+    GEOSGeom_destroy(b);
+    GEOSGeom_destroy(ab);
+    GEOSGeom_destroy(ba);
+}
+
 } // namespace tut