Allow changes to columns in bokeh CDS

.travis.yml

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