Merge pull request #7537 from walkermatt/removeLastPoint

Fix Draw.removeLastPoint exception when no points to remove

src/ol/interaction/draw.js

@@ -168,7 +168,12 @@ ol.interaction.Draw = function(options) {
         var geometry = opt_geometry;
         if (geometry) {
           if (mode === ol.interaction.Draw.Mode_.POLYGON) {
-            geometry.setCoordinates([coordinates[0].concat([coordinates[0][0]])]);
+            if (coordinates[0].length) {
+              // Add a closing coordinate to match the first
+              geometry.setCoordinates([coordinates[0].concat([coordinates[0][0]])]);
+            } else {
+              geometry.setCoordinates([]);
+            }
           } else {
             geometry.setCoordinates(coordinates);
           }

test/spec/ol/interaction/draw.test.js

@@ -585,6 +585,29 @@ describe('ol.interaction.Draw', function() {
       expect(source.getFeatures()).to.have.length(0);
     });
 
+    it('will tolerate removeLastPoint being called when no coordinates', function() {
+
+      // first point
+      simulateEvent('pointermove', 10, 20);
+      simulateEvent('pointerdown', 10, 20);
+      simulateEvent('pointerup', 10, 20);
+
+      // second point
+      simulateEvent('pointermove', 40, 30);
+      simulateEvent('pointerdown', 40, 30);
+      simulateEvent('pointerup', 40, 30);
+
+      simulateEvent('pointermove', 100, 100);
+
+      expect(function() {
+        draw.removeLastPoint();
+        draw.removeLastPoint();
+        draw.removeLastPoint();
+      }).to.not.throwException();
+
+    });
+
+
     it('draws polygon with clicks, finishing on last point', function() {
       // first point
       simulateEvent('pointermove', 10, 20);