DataCube's target and collapsed parameters

I’d like my DataCube to startup with all rows expanded. I thought I’d be able to do this by setting the collapsed parameter of its grouping argument to False, but apparently that’s the default and it doesn’t have the desired effect.

I was then looking into whether I could set the initial value of the target ColumnDataSource to accomplish this goal, but also no luck. See the (not so minimal) working example below, in which I put in a button to allow me to examine the current value of target, and after seeing what it was when fully expanded, I set this as the initial value and re-ran, but this just gave the same initial target as before.

Am I missing a simpler way to do this? Why aren’t my 2 attempts successful?

from bokeh.io import output_file, show, curdoc
from bokeh.models import Button, DataCube, ColumnDataSource, StringFormatter, TableColumn, GroupingInfo, SumAggregator
from bokeh.layouts import row

source = ColumnDataSource(data=dict(
    d0=['A', 'E', 'E', 'E', 'J', 'J', 'M'],
    d1=['B', 'C', 'D', 'H', 'K', 'L', 'N'],
    px=[10,  20,  30,  40,  50,  60,  70 ],
))

#target = ColumnDataSource(data=dict(row_indices=[], labels=[])) # initial
target = ColumnDataSource(data=dict(row_indices=[[0], 0, [1, 2, 3], 1, 2, 3, [4, 5], 4, 5, [6], 6], labels=['A', 'B', 'E', 'C', 'D', 'H', 'J', 'K', 'L', 'M', 'N'])) # after finding out this was what target was equal to after expanding all rows of the datacube

formatter = StringFormatter(font_style='bold')

columns = [
    TableColumn(field='d1', title='Name', width=40, sortable=False, formatter=formatter),
    TableColumn(field='px', title='Price', width=40, sortable=False),
]

grouping = [
    GroupingInfo(getter='d0'),
]

def callback():
    print(cube.target.data)

cube = DataCube(source=source, columns=columns, grouping=grouping, target=target)

button = Button()
button.on_click(callback)

curdoc().add_root(row(button, cube))

Hi @efremdan1,

I tested this, and was also surprised by the behavior you described. We’re looking into it to see whether this is something that needs to be corrected. I’ll get back to you with the resolution on that and any applicable GitHub issue.

I’ve submitted a GH issue here: https://github.com/bokeh/bokeh/issues/10706

As I wrote there, I’m not sure whether it’ll end up being a bugfix or a documentation issue. Stay tuned!