fix selectedpoints clearance under select/lasso drag modes

Author: etpinard

src/traces/scattergl/index.js

@@ -468,6 +468,8 @@ function plot(gd, subplot, cdata) {
     }
 
     var selectMode = dragmode === 'lasso' || dragmode === 'select';
+    scene.selectBatch = null;
+    scene.unselectBatch = null;
 
     // provide viewport and range
     var vpRange = cdata.map(function(cdscatter) {
@@ -500,8 +502,10 @@ function plot(gd, subplot, cdata) {
         if(trace.selectedpoints || selectMode) {
             if(!selectMode) selectMode = true;
 
-            if(!scene.selectBatch) scene.selectBatch = [];
-            if(!scene.unselectBatch) scene.unselectBatch = [];
+            if(!scene.selectBatch) {
+                scene.selectBatch = [];
+                scene.unselectBatch = [];
+            }
 
             // regenerate scene batch, if traces number changed during selection
             if(trace.selectedpoints) {

test/jasmine/tests/gl2d_plot_interact_test.js

@@ -809,11 +809,48 @@ describe('@gl Test gl2d plots', function() {
             var scene = gd._fullLayout._plots.xy._scene;
 
             expect(scene.count).toBe(2);
-            expect(scene.selectBatch).toBeDefined();
-            expect(scene.unselectBatch).toBeDefined();
+            expect(scene.selectBatch).toEqual([[0]]);
+            expect(scene.unselectBatch).toEqual([[]]);
             expect(scene.markerOptions.length).toBe(2);
             expect(scene.markerOptions[1].color).toEqual(new Uint8Array([255, 0, 0, 255]));
             expect(scene.scatter2d.draw).toHaveBeenCalled();
+
+            return Plotly.restyle(gd, 'selectedpoints', null);
+        })
+        .then(function() {
+            var scene = gd._fullLayout._plots.xy._scene;
+            var msg = 'clearing under dragmode select';
+
+            expect(scene.selectBatch).toEqual([], msg);
+            expect(scene.unselectBatch).toEqual([], msg);
+
+            // scattergl uses different pathways for select/lasso & zoom/pan
+            return Plotly.relayout(gd, 'dragmode', 'pan');
+        })
+        .then(function() {
+            var scene = gd._fullLayout._plots.xy._scene;
+            var msg = 'cleared under dragmode pan';
+
+            expect(scene.selectBatch).toEqual([], msg);
+            expect(scene.unselectBatch).toEqual([], msg);
+
+            return Plotly.restyle(gd, 'selectedpoints', [[1, 2], [0]]);
+        })
+        .then(function() {
+            var scene = gd._fullLayout._plots.xy._scene;
+            var msg = 'selecting via API under dragmode pan';
+
+            expect(scene.selectBatch).toEqual([[1, 2], [0]], msg);
+            expect(scene.unselectBatch).toEqual([[0], []], msg);
+
+            return Plotly.restyle(gd, 'selectedpoints', null);
+        })
+        .then(function() {
+            var scene = gd._fullLayout._plots.xy._scene;
+            var msg = 'clearing under dragmode pan';
+
+            expect(scene.selectBatch).toBe(null, msg);
+            expect(scene.unselectBatch).toBe(null, msg);
         })
         .catch(fail)
         .then(done);