Allow changes to columns in bokeh CDS

.travis.yml

@@ -29,7 +29,7 @@ install:
   - conda info -a
   - conda create -q -n test-environment python=$TRAVIS_PYTHON_VERSION flake8 scipy=1.0.0 numpy freetype nose pandas=0.22.0 jupyter ipython=5.4.1 param matplotlib=2.1.2 xarray
   - source activate test-environment
-  - conda install -c conda-forge  iris plotly flexx ffmpeg --quiet
+  - conda install -c conda-forge  iris plotly flexx ffmpeg netcdf4=1.3.1 --quiet
   - conda install -c bokeh datashader dask bokeh=0.12.15 selenium
   - if [[ "$TRAVIS_PYTHON_VERSION" == "3.4" ]]; then
       conda install python=3.4.3;

holoviews/plotting/bokeh/plot.py

@@ -225,6 +225,18 @@ def _update_datasource(self, source, data):
                     source.data.update(converted_data)
                 else:
                     source.stream(data, stream.length)
+            return
+
+        # Determine if the CDS.data requires a full update or simply needs
+        # to be updated, this is done by determining whether newly added
+        # or not updated columns have the same length
+        new_length = [len(v) for v in data.values() if isinstance(v, (list, np.ndarray))]
+        length = [len(v) for v in source.data.values() if isinstance(v, (list, np.ndarray))]
+        not_updated = [k for k in source.data if k not in data]
+        new = [k for k in data if k not in source.data]
+        if ((not_updated and new_length and any(len(source.data[n]) != new_length[0] for n in not_updated))
+            or (new and length and any(len(data[n]) != length[0] for n in new))):
+            source.data = data
         else:
             source.data.update(data)
 

holoviews/plotting/bokeh/tabular.py

@@ -121,4 +121,6 @@ def update_frame(self, key, ranges=None, plot=None):
         source = self.handles['source']
         style = self.lookup_options(element, 'style')[self.cyclic_index]
         data, _, style = self.get_data(element, ranges, style)
+        columns = self._get_columns(element, data)
+        self.handles['plot'].columns = columns
         self._update_datasource(source, data)

tests/plotting/bokeh/testelementplot.py

@@ -121,6 +121,26 @@ def test_element_grid_options(self):
         self.assertEqual(plot.state.ygrid[0].grid_line_width, 1.5)
         self.assertEqual(plot.state.ygrid[0].bounds, (0.3, 0.7))
 
+    def test_change_cds_columns(self):
+        lengths = {'a': 1, 'b': 2, 'c': 3}
+        curve = DynamicMap(lambda a: Curve(range(lengths[a]), a), kdims=['a']).redim.values(a=['a', 'b', 'c'])
+        plot = bokeh_renderer.get_plot(curve)
+        self.assertEqual(sorted(plot.handles['source'].data.keys()), ['a', 'y'])
+        self.assertEqual(plot.state.xaxis[0].axis_label, 'a')
+        plot.update(('b',))
+        self.assertEqual(sorted(plot.handles['source'].data.keys()), ['b', 'y'])
+        self.assertEqual(plot.state.xaxis[0].axis_label, 'b')
+
+    def test_update_cds_columns(self):
+        curve = DynamicMap(lambda a: Curve(range(10), a), kdims=['a']).redim.values(a=['a', 'b', 'c'])
+        plot = bokeh_renderer.get_plot(curve)
+        self.assertEqual(sorted(plot.handles['source'].data.keys()), ['a', 'y'])
+        self.assertEqual(plot.state.xaxis[0].axis_label, 'a')
+        plot.update(('b',))
+        self.assertEqual(sorted(plot.handles['source'].data.keys()), ['a', 'b', 'y'])
+        self.assertEqual(plot.state.xaxis[0].axis_label, 'b')
+
+
 
 class TestColorbarPlot(TestBokehPlot):
 

tests/plotting/bokeh/testtabular.py

@@ -2,6 +2,7 @@
 from unittest import SkipTest
 
 from holoviews.core.options import Store
+from holoviews.core.spaces import DynamicMap
 from holoviews.element import Table
 from holoviews.element.comparison import ComparisonTestCase
 from holoviews.streams import CDSStream
@@ -62,3 +63,13 @@ def test_table_plot_callback(self):
         plot = bokeh_renderer.get_plot(table)
         self.assertEqual(len(plot.callbacks), 1)
         self.assertIsInstance(plot.callbacks[0], CDSCallback)
+
+    def test_table_change_columns(self):
+        lengths = {'a': 1, 'b': 2, 'c': 3}
+        table = DynamicMap(lambda a: Table(range(lengths[a]), a), kdims=['a']).redim.values(a=['a', 'b', 'c'])
+        plot = bokeh_renderer.get_plot(table)
+        self.assertEqual(sorted(plot.handles['source'].data.keys()), ['a'])
+        self.assertEqual(plot.handles['plot'].columns[0].title, 'a')
+        plot.update(('b',))
+        self.assertEqual(sorted(plot.handles['source'].data.keys()), ['b'])
+        self.assertEqual(plot.handles['plot'].columns[0].title, 'b')