[BUG] HoverTool can't adress source with ö

[mosc9575]

Expected behavior

I expect that the HoverTool is able to display information from the data of a ColumnDataSource, even if the key has special letters like ö in it.

Observed behavior

If the key contains a special letter like ö, the HoverTool displays ??? and adds the key without the first letter.

Example code

from bokeh.models import ColumnDataSource
from bokeh.plotting import figure, show, output_notebook
output_notebook()

source = ColumnDataSource(data=dict(
    x=[1, 2, 3, 4, 5],
    y=[2, 5, 8, 2, 7],
    desc=['A', 'b', 'C', 'd', 'E'],
    wörter=['A', 'b', 'C', 'd', 'E'],
))
TOOLTIPS = [("desc", "@desc"), ("Wörter", "@wörter")]
p = figure(width=400, height=400, tooltips=TOOLTIPS, title="Mouse over the dots")
p.circle('x', 'y', size=20, source=source)
show(p)

Technical Information

### Software versions

Python version : 3.10.13 | packaged by conda-forge | (main, Oct 26 2023, 18:07:37) [GCC 12.3.0]
IPython version : 8.14.0
Tornado version : 6.3.3
Bokeh version : 3.3.4
BokehJS static path : /opt/conda/envs/aiva-env/lib/python3.10/site-packages/bokeh/server/static
node.js version : v18.15.0
npm version : 9.5.0
Operating system : Linux-4.19.0-21-amd64-x86_64-with-glibc2.35

Browser name and version

Google Chrome Version 121.0.6167.184 (Offizieller Build) (64-Bit)

[mattpap]

This works:

TOOLTIPS = [("desc", "@desc"), ("Wörter", "@{wörter}")]

i.e. full reference syntax. The short/simplified syntax only works with names that are simple identifiers. Perhaps we could extend that a little bit, if there's a cheap and reliable way of doing this in JS.