HausdorffDistance: Fix crash on collection with empty components

libgeos · Mar 1, 2023 · 05e6b8f · 05e6b8f
1 parent 9e295c0
commit 05e6b8f
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diff --git a/NEWS b/NEWS
@@ -4,6 +4,7 @@ Changes in 3.9.5
 - Bug fixes / improvements:
   - GEOSUnaryUnion: Fix crash on collection containing empty point (GH-830, Dan Baston)
   - IndexedFacetDistance: Fix crash with Inf coordinates (GH-821, Dan Baston)
+  - HausdorffDistance: Fix crash on collection containing empty point (GH-840, Dan Baston)
   - DistanceOp: Fix crash on collection containing empty point (GH-842, Dan Baston)
 
 

diff --git a/src/algorithm/distance/DistanceToPoint.cpp b/src/algorithm/distance/DistanceToPoint.cpp
@@ -40,6 +40,10 @@ DistanceToPoint::computeDistance(const geom::Geometry& geom,
                                  const geom::Coordinate& pt,
                                  PointPairDistance& ptDist)
 {
+    if (geom.isEmpty()) {
+        ptDist.initialize();
+        return;
+    }
     if(const LineString* ls = dynamic_cast<const LineString*>(&geom)) {
         computeDistance(*ls, pt, ptDist);
     }

diff --git a/tests/unit/algorithm/distance/DiscreteHausdorffDistanceTest.cpp b/tests/unit/algorithm/distance/DiscreteHausdorffDistanceTest.cpp
@@ -156,5 +156,21 @@ void object::test<5>
 }
 
 
+
+// Crash on collection with empty components
+// https://github.com/libgeos/geos/issues/840
+template<>
+template<>
+void object::test<7>
+()
+{
+    auto g1 = reader.read("GEOMETRYCOLLECTION (POINT EMPTY, LINESTRING (0 0, 1 1))");
+    auto g2 = reader.read("POINT (1 2)");
+    auto g3 = reader.read("LINESTRING (0 0, 1 1)");
+
+    ensure_equals(DiscreteHausdorffDistance::distance(*g1, *g2),
+                  DiscreteHausdorffDistance::distance(*g2, *g3));
+}
+
 } // namespace tut