There is no tornado available in Pyodide https://pyodide.org/en/stable/usage/packages-in-pyodide.html

That makes sense, but the Bokeh example used to work in the older version of PyScript. If you look at my code, all I did was take the Bokeh example from the PyScript website and update PyScript to the latest the version.

is Bokeh using latest 3.6.0 version or it's pinned to an old one? 🤔

You will need to find the version of bokeh that was used in the example.
Maybe the author forgot to pin the bokeh version into the toml file - which is why it doesn't work now - because the bokeh people added tornado recently.

Looking at the release history:

• https://pypi.org/project/bokeh/#history

Maybe "bokeh==3.6.0" is worth a try

If I look at one of the bokeh examples:

• https://pyscript.com/@examples/bokeh/latest?files=README.md,pyscript.toml
• We can see in the toml file that
• "bokeh==3.2.2"

While probably being an upstream dependency issue (from the looks of it, bokeh doesn't need tornado unless you are using the server), I think this issue is actually an opportunity to fix the user experience. Iirc, Bokeh is not the only data viz package that depends on Tornado for features that are not relevant in wasm based python interpreters. Adding a plugin or something like that, that installs and patches dependencies to make things work transparently would benefit the user experience.

I don't think this change should be done at the pyscript codebase level though, or at least we should put some thought into it...

Adding a plugin or something like that, that installs and patches dependencies to make things work transparently would benefit the user experience.

all I can think about is a packages_ignore_list in the TOML/JSON config file that requires a bit of extra parsing but it could help removing unnecessary packages ... although, it's not under our responsibility to "poison" the micropip resolution and I think it does that automatically so I fully agree we should try to improve but I don't know how and I am going to find out if pyodide already offers such feature, in which case we can help mitigating the issue, or at least document it!

ok ... after a quick search I couldn't find any way to tell micropip that tornado is not really needed but I wonder if adding the ability to mock packages could help solving those one missing or conflicting ... https://micropip.pyodide.org/en/v0.7.1/project/api.html#micropip.add_mock_package

I still think not pinning packages is still "the elephant in the room" and we should stress all over the docs that issues like this one will keep happening every single time a package introduces a dependency that is not available, or changes its API in a breaking way.