Holoviews: DynamicMap hover tool does not update with chosen variable

[dnowacki-usgs]

Migrating from SO.

The following code creates a DynamicMap allowing you to choose from two variables:

import holoviews as hv
import pandas as pd
import numpy as np
hv.extension('bokeh')

df = pd.DataFrame()
df['time'] = pd.date_range('2018-01-01', '2018-01-31')
df['var1'] = np.linspace(0, 1, len(df['time']))
df['var2'] = np.ones(df['var1'].shape)

def load_symbol(var):
    return hv.Curve(df, ('time', 'Time'), var)

variables = ['var1', 'var2']
dmap = hv.DynamicMap(load_symbol, kdims='Variable').redim.values(Variable=variables)

dmap.opts(framewise=True, tools=['hover'])

However, the hover tool continues to show the value for var1 even when plotting var2.

Correct behavior for var1:

Incorrect behavior for var2:

The tooltip still shows the var1 value of 0.2, but it should read 1.

What's going on here?

[philippjfr]

Thank you, this is indeed a bug. Originally HoloViews did not support changing the dimensions of an element, this changed a long time ago but it seems like we never implemented updates to the HoverTool tooltips.

[jorloplaz]

This still doesn't work if one tries to use a custom tooltip instead of the default one. Changing slightly the previous example:

import holoviews as hv
import pandas as pd
import numpy as np
hv.extension('bokeh')
from bokeh.models import HoverTool

df = pd.DataFrame()
df['time'] = pd.date_range('2018-01-01', '2018-01-31')
df['var1'] = np.linspace(0, 1, len(df['time']))
df['var2'] = np.ones(df['var1'].shape)

def load_symbol(var):
    return hv.Curve(df, [('time', 'Time')], [var]).opts(tools=[HoverTool(tooltips=[('value', f'@{var}')])])

dmap = (hv.DynamicMap(load_symbol, kdims='var').redim.values(var=['var1', 'var2'])
            .opts(framewise=True))
dmap

Makes value not to update.

I think this is related to the way the issue was implemented. There's an 'hv_created' tag in a sort of internal tooltip, which is assumed to always be present. What if the user instead provides another tooltip instance which should be the one to be updated?