Ensure CDSStream.data is initialized correctly (#2321)

holoviews/plotting/bokeh/callbacks.py

@@ -853,6 +853,11 @@ class CDSCallback(Callback):
     models = ['source']
     on_changes = ['data']
 
+    def initialize(self):
+        super(CDSCallback, self).initialize()
+        for stream in self.streams:
+            stream.update(data=self.plot_handles['source'].data)
+
     def _process_msg(self, msg):
         for col, values in msg['data'].items():
             if isinstance(values, dict):
@@ -945,6 +950,9 @@ def initialize(self):
         plot.state.tools.append(box_tool)
         self.plot.state.renderers.remove(plot.handles['glyph_renderer'])
         super(BoxEditCallback, self).initialize()
+        for stream in self.streams:
+            stream.update(data=self._process_msg({'data': data})['data'])
+
 
     def _process_msg(self, msg):
         data = super(BoxEditCallback, self)._process_msg(msg)['data']

tests/plotting/bokeh/testcallbacks.py

@@ -42,6 +42,14 @@ def test_point_draw_callback(self):
         callback.on_msg({'data': data})
         self.assertEqual(point_draw.element, Points(data))
 
+    def test_point_draw_callback_initialize(self):
+        points = Points([(0, 1)])
+        point_draw = PointDraw(source=points)
+        plot = bokeh_renderer.get_plot(points)
+        self.assertIsInstance(plot.callbacks[0], PointDrawCallback)
+        data = {'x': [0], 'y': [1]}
+        self.assertEqual(point_draw.element, points)
+
     def test_point_draw_callback_with_vdims(self):
         points = Points([(0, 1, 'A')], vdims=['A'])
         point_draw = PointDraw(source=points)
@@ -75,6 +83,13 @@ def test_poly_draw_callback_with_vdims(self):
                             {'x': [3, 4, 5], 'y': [3, 4, 5], 'A': 2}], vdims=['A'])
         self.assertEqual(poly_draw.element, element)
 
+    def test_box_edit_callback(self):
+        boxes = Polygons([Box(0, 0, 1)])
+        box_edit = BoxEdit(source=boxes)
+        plot = bokeh_renderer.get_plot(boxes)
+        self.assertIsInstance(plot.callbacks[0], BoxEditCallback)
+        self.assertEqual(box_edit.element, boxes)
+
     def test_box_edit_callback(self):
         boxes = Polygons([Box(0, 0, 1)])
         box_edit = BoxEdit(source=boxes)