From 136e8e486f13e590da6096c196c49bc6ca272b2c Mon Sep 17 00:00:00 2001
From: Martin Davis <mtnclimb@gmail.com>
Date: Tue, 5 Dec 2023 12:53:12 -0800
Subject: [PATCH] Fix PreparedPolygonContains for GC with MultiPoint (#1008)

---
 src/geom/prep/AbstractPreparedPolygonContains.cpp | 14 ++++++--------
 tests/unit/geom/prep/PreparedGeometryTest.cpp     | 14 ++++++++++++++
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/src/geom/prep/AbstractPreparedPolygonContains.cpp b/src/geom/prep/AbstractPreparedPolygonContains.cpp
index cfc87436cd..f0dbdeacc3 100644
--- a/src/geom/prep/AbstractPreparedPolygonContains.cpp
+++ b/src/geom/prep/AbstractPreparedPolygonContains.cpp
@@ -186,7 +186,6 @@ bool AbstractPreparedPolygonContains::evalPointTestGeom(const Geometry *geom, Lo
     if (outermostLoc == Location::EXTERIOR) {
         return false;
     }
-
     // For the Covers predicate, we can return true
     // since no Points are on the exterior of the target
     // geometry.
@@ -195,19 +194,18 @@ bool AbstractPreparedPolygonContains::evalPointTestGeom(const Geometry *geom, Lo
     }
 
     // For the Contains predicate, we need to test if any
-    // of those points lie in the interior of the target
+    // of the test points lie in the interior of the target
     // geometry.
     if (outermostLoc == Location::INTERIOR) {
         return true;
     }
 
-    if (geom->getNumGeometries() > 1) {
-        // for MultiPoint, try to find at least one point
-        // in interior
-        return isAnyTestComponentInTargetInterior(geom);
+    // a single point must not be in interior
+    if (geom->getNumPoints() <= 1) {
+        return false;
     }
-
-    return false;
+    // for multiple points have to check all
+    return isAnyTestComponentInTargetInterior(geom);
 }
 
 //
diff --git a/tests/unit/geom/prep/PreparedGeometryTest.cpp b/tests/unit/geom/prep/PreparedGeometryTest.cpp
index ffdd90faf0..c1df1abac4 100644
--- a/tests/unit/geom/prep/PreparedGeometryTest.cpp
+++ b/tests/unit/geom/prep/PreparedGeometryTest.cpp
@@ -84,5 +84,19 @@ void object::test<2>
     ensure( pg1->intersects(g2.get()) );
 }
 
+// See https://github.com/libgeos/geos/issues/1007
+template<>
+template<>
+void object::test<3>
+()
+{
+    g1 = reader.read( "MULTIPOLYGON(((-60 -50,-70 -50,-60 -40,-60 -50)))" );
+    g2 = reader.read( "GEOMETRYCOLLECTION(MULTIPOINT((-60 -50),(-63 -49)))" );
+
+    pg1 = prep::PreparedGeometryFactory::prepare(g1.get());
+
+    ensure(  g1->contains(g2.get()) );
+    ensure( pg1->contains(g2.get()) );
+}
 
 } // namespace tut