_repr_json_ favored over widget output in notebooks with ipywidgets v8.0.1

[lukasbindreiter]

Description

I noticed that with a recent upgrade to ipywidgets==8.0.1 the behaviour of widgets that also have a _repr_json_ method changed.

Reproduce

import ipywidgets

class MyFloatProgress(ipywidgets.FloatProgress):
    def _repr_json_(self):
        return {"value": self.value}

MyFloatProgress(30)

Expected behavior

Context

This may seem like a pretty niche issue, but it is actually the underlying cause why tqdm.notebook doesn't work anymore currently with ipywidgets==8.0.1:

See:
tqdm/tqdm#1359

If using JupyterLab

• JupyterLab version:
  3.4.5

Installed Labextensions

JupyterLab v3.4.5
/home/grasp/.venv/share/jupyter/labextensions
        dask-labextension v5.3.0 enabled OK (python, dask_labextension)
        jupyter-matplotlib v0.11.2 enabled OK
        jupyterlab-link-share v0.2.4 enabled OK (python, jupyterlab-link-share)
        jupyterlab-system-monitor v0.8.0 enabled OK (python, jupyterlab-system-monitor)
        jupyterlab-topbar-extension v0.6.1 enabled OK (python, jupyterlab-topbar)
        jupyterlab_pygments v0.2.2 enabled OK (python, jupyterlab_pygments)
        @hadim/jupyter-archive v3.3.1 enabled OK (python, jupyter-archive)
        @jupyter-server/resource-usage v0.6.1 enabled OK (python, jupyter-resource-usage)
        @jupyter-widgets/jupyterlab-manager v5.0.2 enabled OK (python, jupyterlab_widgets)
        @jupyterlab/server-proxy v3.2.1 enabled OK
        @ryantam626/jupyterlab_code_formatter v1.5.3 enabled OK (python, jupyterlab-code-formatter)
Other labextensions (built into JupyterLab)

app dir: /home/grasp/.venv/share/jupyter/lab

@jupyterlab/geojson-extension v3.1.2 enabled OK

@jupyterlab/katex-extension v3.2.2 enabled OK

@jupyterlab/vega3-extension v3.1.3 enabled OK
Disabled extensions:

@jupyterlab/mathjax2-extension:plugin

[jasongrout]

Thanks for reporting this. We already register the widget rendermime factories with rank 0 to beat out default renderers:

ipywidgets/python/jupyterlab_widgets/src/plugin.ts

Lines 222 to 229 in e722a0d

	rendermime.addFactory(
	{
	safe: false,
	mimeTypes: [WIDGET_VIEW_MIMETYPE],
	createRenderer: (options) => new WidgetRenderer(options),
	},
	0
	);

ipywidgets/python/jupyterlab_widgets/src/plugin.ts

Line 127 in e722a0d

rendermime.addFactory(

However, it looks like the json renderer also registers itself as rank 0, so sometimes (always?) it takes precedence:

https://github.com/jupyterlab/jupyterlab/blob/4231895bee40977e1199e9a643c51a743237cb4a/packages/json-extension/src/index.tsx#L97

So we can move to a negative rank in our code, and/or ask upstream jlab why the json renderer is rank 0 instead of, say, rank 50 if it needs to beat out some other default renderers.

[jasongrout]

So we can move to a negative rank in our code, and/or ask upstream jlab why the json renderer is rank 0 instead of, say, rank 50 if it needs to beat out some other default renderers.

I moved our rank to -10 in #3579

[jasongrout]

@lukasbindreiter, this should be fixed in ipywidgets 8.0.2, which was just published.

[lukasbindreiter]

Awesome, thanks 😄