ipywidgets 7.7.4 breaks shinywidgets

[bartverweire]

• shinywidgets version: 0.1.15
• shiny version : 0.2.10
• Python version: 3.10.2
• Operating System: Windows
• ipywidgets version: 7.7.4

Description

Trying to display a plotly output widget. When using ipywidgets 7.7.4, this fails with

Traceback (most recent call last):
  File "C:\Tools\Anaconda3\envs\python_310\lib\site-packages\shiny\session\_session.py", line 1017, in output_obs
    message[output_name] = fn()
  File "C:\Tools\Anaconda3\envs\python_310\lib\site-packages\shinywidgets\_shinywidgets.py", line 168, in __call__
    return run_coro_sync(self.run())
  File "C:\Tools\Anaconda3\envs\python_310\lib\site-packages\shiny\_utils.py", line 218, in run_coro_sync
    coro.send(None)
  File "C:\Tools\Anaconda3\envs\python_310\lib\site-packages\shinywidgets\_shinywidgets.py", line 171, in run
    x = await self._fn()
  File "C:\Tools\Anaconda3\envs\python_310\lib\site-packages\shiny\_utils.py", line 173, in fn_async
    return fn()
  File "C:\Workspace\Python\Shiny\Clean\app.py", line 26, in plot
    fig = go.FigureWidget(fig)
  File "C:\Tools\Anaconda3\envs\python_310\lib\site-packages\plotly\graph_objs\_figurewidget.py", line 629, in __init__
    super(FigureWidget, self).__init__(data, layout, frames, skip_invalid, **kwargs)
  File "C:\Tools\Anaconda3\envs\python_310\lib\site-packages\plotly\basewidget.py", line 117, in __init__
    super(BaseFigureWidget, self).__init__(
  File "C:\Tools\Anaconda3\envs\python_310\lib\site-packages\plotly\basedatatypes.py", line 461, in __init__
    super(BaseFigure, self).__init__()
  File "C:\Tools\Anaconda3\envs\python_310\lib\site-packages\ipywidgets\widgets\widget.py", line 479, in __init__
    Widget._call_widget_constructed(self)
  File "C:\Tools\Anaconda3\envs\python_310\lib\site-packages\ipywidgets\widgets\widget.py", line 338, in _call_widget_constructed
    Widget._widget_construction_callback(widget)
  File "C:\Tools\Anaconda3\envs\python_310\lib\site-packages\shinywidgets\_shinywidgets.py", line 74, in init_shiny_widget
    old_comm_klass = copy.copy(Widget.comm.klass)  # type: ignore
AttributeError: 'Any' object has no attribute 'klass'

What I Did

Here's a simple app demonstrating the issue

from shiny import App, render, ui
from shinywidgets import *
import pandas as pd

import plotly.express as px
import plotly.graph_objects as go

df = pd.DataFrame({"x": [1, 2, 3], "y": [2, 0.5, 1], "z": [1, 1, 1]}, index=[0, 1, 2])

app_ui = ui.page_fluid(
    ui.h2("Hello Plotly!"),
    output_widget("plot")
)

def server(input, output, session):
    @output
    @render_widget
    def plot():
        fig = px.bar(df, x="x", y="y", color="z",
                     orientation="v",
                     height=400
                     )

        return go.FigureWidget(fig)

app = App(app_ui, server)

then run

shiny run --reload app.py

The issue disappears when switching back to ipywidgets==7.7.3.

Kind Regards

Bart

[cpsievert]

Are you sure 7.7.4 introduced this failure? It looks like the 8.0.5 (released yesterday) introduced it.

[bartverweire]

Yes, I'm sure that this occurs with 7.7.4 :

...
AttributeError: 'Any' object has no attribute 'klass'
INFO:     Shutting down
INFO:     connection closed
INFO:     Waiting for application shutdown.
INFO:     Application shutdown complete.
INFO:     Finished server process [3632]
INFO:     Stopping reloader process [9656]
(venv) PS C:\Workspace\Python\Shiny\Clean> ^C
(venv) PS C:\Workspace\Python\Shiny\Clean> pip show ipywidgets
Name: ipywidgets
Version: 7.7.4
Summary: IPython HTML widgets for Jupyter