From 516f2d7854db706eedf4054c55da6c7116d3edad Mon Sep 17 00:00:00 2001
From: Martin Davis <mtnclimb@gmail.com>
Date: Wed, 29 Nov 2023 10:14:35 -0800
Subject: [PATCH] Fix InteriorPoint for MultiLineString with EMPTY

---
 .../jts/algorithm/InteriorPointLine.java      |  6 ++++++
 .../jts/algorithm/InteriorPointTest.java      |  4 ++++
 .../testxml/general/TestInteriorPoint.xml     | 20 ++++++++++++++++---
 3 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/modules/core/src/main/java/org/locationtech/jts/algorithm/InteriorPointLine.java b/modules/core/src/main/java/org/locationtech/jts/algorithm/InteriorPointLine.java
index ca5a9832d4..0594a4817f 100644
--- a/modules/core/src/main/java/org/locationtech/jts/algorithm/InteriorPointLine.java
+++ b/modules/core/src/main/java/org/locationtech/jts/algorithm/InteriorPointLine.java
@@ -69,6 +69,9 @@ public Coordinate getInteriorPoint()
    */
   private void addInterior(Geometry geom)
   {
+    if (geom.isEmpty())
+      return;
+    
     if (geom instanceof LineString) {
       addInterior(geom.getCoordinates());
     }
@@ -93,6 +96,9 @@ private void addInterior(Coordinate[] pts)
    */
   private void addEndpoints(Geometry geom)
   {
+    if (geom.isEmpty())
+      return;
+    
     if (geom instanceof LineString) {
       addEndpoints(geom.getCoordinates());
     }
diff --git a/modules/core/src/test/java/org/locationtech/jts/algorithm/InteriorPointTest.java b/modules/core/src/test/java/org/locationtech/jts/algorithm/InteriorPointTest.java
index bed933f7fe..52aee7761d 100644
--- a/modules/core/src/test/java/org/locationtech/jts/algorithm/InteriorPointTest.java
+++ b/modules/core/src/test/java/org/locationtech/jts/algorithm/InteriorPointTest.java
@@ -50,6 +50,10 @@ public void testPolygonZeroArea() {
     checkInteriorPoint(read("POLYGON ((10 10, 10 10, 10 10, 10 10))"), new Coordinate(10, 10));
   }
   
+  public void testMultiLineWithEmpty() {
+    checkInteriorPoint(read("MULTILINESTRING ((0 0, 1 1), EMPTY)"), new Coordinate(0, 0));
+  }
+  
   public void testAll() throws Exception
   {
     checkInteriorPointFile(TestFiles.getResourceFilePath("world.wkt"));
diff --git a/modules/tests/src/test/resources/testxml/general/TestInteriorPoint.xml b/modules/tests/src/test/resources/testxml/general/TestInteriorPoint.xml
index 9c3cbdc05b..b6450dbd0f 100644
--- a/modules/tests/src/test/resources/testxml/general/TestInteriorPoint.xml
+++ b/modules/tests/src/test/resources/testxml/general/TestInteriorPoint.xml
@@ -1,5 +1,4 @@
 <run>
-  <precisionModel scale="1.0" offsetx="0.0" offsety="0.0"/>
 
 <case>
   <desc>P - empty</desc>
@@ -38,7 +37,7 @@
   <desc>L - linestring with single segment</desc>
   <a>    LINESTRING (0 0, 7 14)
   </a>
-<test><op name="getInteriorPoint" arg1="A" >   POINT (7 14)   </op></test>
+<test><op name="getInteriorPoint" arg1="A" >   POINT (0 0)   </op></test>
 </case>
 
 <case>
@@ -68,6 +67,13 @@
 <test><op name="getInteriorPoint" arg1="A" >    POINT (180 200)   </op></test>
 </case>
 
+<case>
+  <desc>mL - multilinestring with empty</desc>
+  <a>    MULTILINESTRING ((0 0, 1 1), EMPTY)
+  </a>
+<test><op name="getInteriorPoint" arg1="A" >    POINT (0 0)   </op></test>
+</case>
+
 <case>
   <desc>A - box</desc>
   <a>    POLYGON ((0 0, 0 10, 10 10, 10 0, 0 0))
@@ -93,7 +99,7 @@
   <desc>A - polygon with horizontal segment at centre (narrower L shape)</desc>
   <a>    POLYGON ((0 2, 0 4, 3 4, 3 0, 2 0, 2 2, 0 2))
 	</a>
-<test><op name="getInteriorPoint" arg1="A" >    POINT (2 3)   </op></test>
+<test><op name="getInteriorPoint" arg1="A" >    POINT (1.5 3)   </op></test>
 </case>
 
 <case>
@@ -103,6 +109,14 @@
 <test><op name="getInteriorPoint" arg1="A" >    POINT (115 200)  </op></test>
 </case>
 
+
+<case>
+  <desc>mA - multipolygon with empty</desc>
+  <a>    MULTIPOLYGON (((0 2, 0 4, 3 4, 3 0, 2 0, 2 2, 0 2)), EMPTY)
+  </a>
+<test><op name="getInteriorPoint" arg1="A" >    POINT (1.5 3)  </op></test>
+</case>
+
 <case>
   <desc>GC - collection of polygons, lines, points</desc>
   <a>    GEOMETRYCOLLECTION (POLYGON ((0 40, 40 40, 40 0, 0 0, 0 40)),