Embedding editable sliders fails (EditableFloatSlider, EditableIntSlider)

[alcrene]

ALL software version info

Panel: 1.3.8
Python: 3.10.12
OS: Linux

Description of expected behavior and the observed behavior

Calling .embed() on a layout containing either a EditableFloatSlider or EditableIntSlider raises an AttributeError.

In both cases, the code ends up in ContinuousSlider._get_embed_state, but this line

panel/panel/widgets/slider.py

Line 122 in ebe8d66

w_model, parent = self._models[ref]

does not actually assign the slider object into w_model (instead it assigns a Column, which contains both the slider, its label and spinner widget). Then a few lines later, this fails

panel/panel/widgets/slider.py

Line 126 in ebe8d66

start, end, step = w_model.start, w_model.end, w_model.step

because since w_model is a Column, it has no start attribute.

Complete, minimal, self-contained example code that reproduces the issue

import panel as pn
pn.extension()
layout = pn.Column(pn.widgets.EditableIntSlider())
layout.embed()

The error also occurs with EditableIntSlider.

It does not occur with EditableRangeSlider, IntSlider or FloatSlider.

Stack traceback and/or browser JavaScript console output

File ~/.cache/pypoetry/virtualenvs/ergm-sampling-nsRVGxGR-py3.10/lib/python3.10/site-packages/panel/viewable.py:942, in Viewable.embed(self, max_states, max_opts, json, json_prefix, save_path, load_path, progress, states)
    912 def embed(
    913     self, max_states: int = 1000, max_opts: int = 3, json: bool = False,
    914     json_prefix: str = '', save_path: str = './', load_path: Optional[str] = None,
    915     progress: bool = False, states={}
    916 ) -> None:
    917     """
    918     Renders a static version of a panel in a notebook by evaluating
    919     the set of states defined by the widgets in the model. Note
   (...)
    940       A dictionary specifying the widget values to embed for each widget
    941     """
--> 942     return render_embed(
    943         self, max_states, max_opts, json, json_prefix, save_path,
    944         load_path, progress, states
    945     )

File ~/.cache/pypoetry/virtualenvs/ergm-sampling-nsRVGxGR-py3.10/lib/python3.10/site-packages/panel/io/notebook.py:522, in render_embed(panel, max_states, max_opts, json, json_prefix, save_path, load_path, progress, states)
    520 with config.set(embed=True):
    521     model = panel.get_root(doc, comm)
--> 522     embed_state(panel, model, doc, max_states, max_opts,
    523                 json, json_prefix, save_path, load_path, progress,
    524                 states)
    525 return Mimebundle(render_model(model))

File ~/.cache/pypoetry/virtualenvs/ergm-sampling-nsRVGxGR-py3.10/lib/python3.10/site-packages/panel/io/embed.py:271, in embed_state(panel, model, doc, max_states, max_opts, json, json_prefix, save_path, load_path, progress, states)
    268     continue
    270 # Get data which will let us record the changes on widget events
--> 271 w, w_model, vals, getter, on_change, js_getter = widget._get_embed_state(
    272     model, states.get(widget), max_opts)
    273 w_type = w._widget_type
    274 if isinstance(w, DiscreteSlider):

File ~/.cache/pypoetry/virtualenvs/ergm-sampling-nsRVGxGR-py3.10/lib/python3.10/site-packages/panel/widgets/slider.py:126, in ContinuousSlider._get_embed_state(self, root, values, max_opts)
    123 _, _, doc, comm = state._views[ref]
    125 # Compute sampling
--> 126 start, end, step = w_model.start, w_model.end, w_model.step
    127 if values is None:
    128     span = end-start

File ~/.cache/pypoetry/virtualenvs/ergm-sampling-nsRVGxGR-py3.10/lib/python3.10/site-packages/bokeh/core/has_props.py:367, in HasProps.__getattr__(self, name)
    364 if isinstance(descriptor, property): # Python property
    365     return super().__getattribute__(name)
--> 367 self._raise_attribute_error_with_matches(name, properties)

File ~/.cache/pypoetry/virtualenvs/ergm-sampling-nsRVGxGR-py3.10/lib/python3.10/site-packages/bokeh/core/has_props.py:375, in HasProps._raise_attribute_error_with_matches(self, name, properties)
    372 if not matches:
    373     matches, text = sorted(properties), "possible"
--> 375 raise AttributeError(f"unexpected attribute {name!r} to {self.__class__.__name__}, {text} attributes are {nice_join(matches)}")

AttributeError: unexpected attribute 'start' to Column, possible attributes are align, aspect_ratio, auto_scroll_limit, children, context_menu, css_classes, disabled, flow_mode, height, height_policy, js_event_callbacks, js_property_callbacks, margin, max_height, max_width, min_height, min_width, name, resizable, scroll_button_threshold, scroll_position, sizing_mode, spacing, styles, stylesheets, subscribed_events, syncable, tags, view_latest, visible, width or width_policy