plotting/bokeh/util.py depends on matplotlib even for bokeh backend

[cnblevins]

This is interesting because I can get hv.Table to work, but hv.Bars is throwing the following exception:

Traceback (most recent call last):
File "/app/.heroku/python/lib/python3.6/site-packages/holoviews/plotting/bokeh/util.py", line 120, in mpl_to_bokeh
v = colors.ColorConverter.colors.get(v, v)
AttributeError: 'NoneType' object has no attribute 'ColorConverter'
and
File "/app/.heroku/python/lib/python3.6/site-packages/holoviews/core/options.py", line 165, in exit
raise AbbreviatedException(etype, value, traceback)
holoviews.core.options.AbbreviatedException: AbbreviatedException: AttributeError: 'NoneType' object has no attribute 'ColorConverter'

The exception traces back to the following line in my code:
graph = hv.renderer('bokeh').server_doc(df3)

Details:

from requirements.txt:

bokeh==0.12.6
holoviews==1.8.2

from app.py:

import holoviews as hv
hv.extension('bokeh')

and

def graph_alpha(dataframe):
    # function to create a graph for the alpha cash flow dataframe
    df1=dataframe 
    df1['date'] = df1.date.astype('datetime64[ns]')

    k_dims = [('date','Date')]
    val_dims = [('netincome', 'EBITDA')]

    plot_opts = dict(fill_color='#00AA00')

    df2 = hv.Table(df1,kdims=k_dims, vdims=val_dims)
    df3 = hv.Bars(df1,kdims=k_dims, vdims=val_dims)
    #df3 = hv.Bars(df1,kdims=k_dims, vdims=val_dims).opts(plot=plot_opts)
    #df3 = hv.Bars(df2).opts(plot=plot_opts)
    #df3 = hv.Bars(df2).opts(style=plot_opts)
    graph = hv.renderer('bokeh').server_doc(df3)

    return graph 

Any thoughts on this?

I looked through all the open and closed issues, and didn't see this one.
Hope we can figure it out.

Chad

[jbednar]

Looks like there is a dependency on matplotlib being installed. Table might not need the colors module from matplotlib, but bars apparently does. Try conda installing matplotlib? We've eliminated most dependencies on matplotlib from the bokeh code, but I think there are still a few, deliberate or not.

[cnblevins]

That was it.
Installed matplotlib 2.0.2 and hv.Bars now works.

Thanks.

[jbednar]

Good. I'll leave this open, because it looks like we need to do some more tidying to avoid that requirement.

[philippjfr]

This has now been fixed.

[github-actions]

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