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DeprecationWarning: Passing unrecognized arguments to super(Toolbar).__init__(). #611
Description
Describe the issue
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
File ~/.miniforge/lib/python3.13/site-packages/traitlets/traitlets.py:1379, in HasTraits.__init__(self, *args, **kwargs)
1378 try:
-> [1379](https://file+.vscode-resource.vscode-cdn.net/home/firestar/NAOC/HVC-catalog/Test/~/.miniforge/lib/python3.13/site-packages/traitlets/traitlets.py:1379) super().__init__(*super_args, **super_kwargs)
1380 except TypeError as e:
TypeError: NavigationToolbar2WebAgg.__init__() missing 1 required positional argument: 'canvas'
During handling of the above exception, another exception occurred:
DeprecationWarning Traceback (most recent call last)
Cell In[24], [line 4](vscode-notebook-cell:?execution_count=24&line=4)
2 cluster_id = hvc_candidates[i]
3 moment_0_crop, extent, xc, yc, a, b, theta, area = cluster_params[i]
----> [4](vscode-notebook-cell:?execution_count=24&line=4) fig, ax = plt.subplots(1, 2, figsize=[10, 4])
5 im = ax[0].imshow(
6 moment_0_crop,
7 extent=extent,
(...) 10 interpolation="none",
11 )
12 cs = ax[0].contour(
13 moment_0_crop,
14 levels=[0.5 * np.max(moment_0_crop)],
(...) 18 linestyles="solid",
19 )
File ~/.miniforge/lib/python3.13/site-packages/matplotlib/pyplot.py:1776, in subplots(nrows, ncols, sharex, sharey, squeeze, width_ratios, height_ratios, subplot_kw, gridspec_kw, **fig_kw)
1621 def subplots(
1622 nrows: int = 1, ncols: int = 1, *,
1623 sharex: bool | Literal["none", "all", "row", "col"] = False,
(...) 1630 **fig_kw
1631 ) -> tuple[Figure, Any]:
1632 """
1633 Create a figure and a set of subplots.
1634
(...) 1774
1775 """
-> [1776](https://file+.vscode-resource.vscode-cdn.net/home/firestar/NAOC/HVC-catalog/Test/~/.miniforge/lib/python3.13/site-packages/matplotlib/pyplot.py:1776) fig = figure(**fig_kw)
1777 axs = fig.subplots(nrows=nrows, ncols=ncols, sharex=sharex, sharey=sharey,
1778 squeeze=squeeze, subplot_kw=subplot_kw,
1779 gridspec_kw=gridspec_kw, height_ratios=height_ratios,
1780 width_ratios=width_ratios)
1781 return fig, axs
File ~/.miniforge/lib/python3.13/site-packages/matplotlib/pyplot.py:1041, in figure(num, figsize, dpi, facecolor, edgecolor, frameon, FigureClass, clear, **kwargs)
1031 if len(allnums) == max_open_warning >= 1:
1032 _api.warn_external(
1033 f"More than {max_open_warning} figures have been opened. "
1034 f"Figures created through the pyplot interface "
(...) 1038 f"Consider using `matplotlib.pyplot.close()`.",
1039 RuntimeWarning)
-> [1041](https://file+.vscode-resource.vscode-cdn.net/home/firestar/NAOC/HVC-catalog/Test/~/.miniforge/lib/python3.13/site-packages/matplotlib/pyplot.py:1041) manager = new_figure_manager(
1042 num, figsize=figsize, dpi=dpi,
1043 facecolor=facecolor, edgecolor=edgecolor, frameon=frameon,
1044 FigureClass=FigureClass, **kwargs)
1045 fig = manager.canvas.figure
1046 if fig_label:
File ~/.miniforge/lib/python3.13/site-packages/matplotlib/pyplot.py:551, in new_figure_manager(*args, **kwargs)
549 """Create a new figure manager instance."""
550 _warn_if_gui_out_of_main_thread()
--> [551](https://file+.vscode-resource.vscode-cdn.net/home/firestar/NAOC/HVC-catalog/Test/~/.miniforge/lib/python3.13/site-packages/matplotlib/pyplot.py:551) return _get_backend_mod().new_figure_manager(*args, **kwargs)
File ~/.miniforge/lib/python3.13/site-packages/matplotlib/backend_bases.py:3504, in _Backend.new_figure_manager(cls, num, *args, **kwargs)
3502 fig_cls = kwargs.pop('FigureClass', Figure)
3503 fig = fig_cls(*args, **kwargs)
-> [3504](https://file+.vscode-resource.vscode-cdn.net/home/firestar/NAOC/HVC-catalog/Test/~/.miniforge/lib/python3.13/site-packages/matplotlib/backend_bases.py:3504) return cls.new_figure_manager_given_figure(num, fig)
File ~/.miniforge/lib/python3.13/site-packages/ipympl/backend_nbagg.py:430, in _Backend_ipympl.new_figure_manager_given_figure(num, figure)
428 if 'nbagg.transparent' in rcParams and rcParams['nbagg.transparent']:
429 figure.patch.set_alpha(0)
--> [430](https://file+.vscode-resource.vscode-cdn.net/home/firestar/NAOC/HVC-catalog/Test/~/.miniforge/lib/python3.13/site-packages/ipympl/backend_nbagg.py:430) manager = FigureManager(canvas, num)
432 if is_interactive():
433 _Backend_ipympl._to_show.append(figure)
File ~/.miniforge/lib/python3.13/site-packages/ipympl/backend_nbagg.py:402, in FigureManager.__init__(self, canvas, num)
400 FigureManagerWebAgg.__init__(self, canvas, num)
401 self.web_sockets = [self.canvas]
--> [402](https://file+.vscode-resource.vscode-cdn.net/home/firestar/NAOC/HVC-catalog/Test/~/.miniforge/lib/python3.13/site-packages/ipympl/backend_nbagg.py:402) self.toolbar = Toolbar(self.canvas)
File ~/.miniforge/lib/python3.13/site-packages/ipympl/backend_nbagg.py:126, in Toolbar.__init__(self, canvas, *args, **kwargs)
125 def __init__(self, canvas, *args, **kwargs):
--> [126](https://file+.vscode-resource.vscode-cdn.net/home/firestar/NAOC/HVC-catalog/Test/~/.miniforge/lib/python3.13/site-packages/ipympl/backend_nbagg.py:126) DOMWidget.__init__(self, *args, **kwargs)
127 NavigationToolbar2WebAgg.__init__(self, canvas, *args, **kwargs)
129 self.on_msg(self.canvas._handle_message)
File ~/.miniforge/lib/python3.13/site-packages/ipywidgets/widgets/widget.py:503, in Widget.__init__(self, **kwargs)
501 """Public constructor"""
502 self._model_id = kwargs.pop('model_id', None)
--> [503](https://file+.vscode-resource.vscode-cdn.net/home/firestar/NAOC/HVC-catalog/Test/~/.miniforge/lib/python3.13/site-packages/ipywidgets/widgets/widget.py:503) super().__init__(**kwargs)
505 Widget._call_widget_constructed(self)
506 self.open()
File ~/.miniforge/lib/python3.13/site-packages/traitlets/traitlets.py:1385, in HasTraits.__init__(self, *args, **kwargs)
1383 arg_s_list.append(f"{k}={v!r}")
1384 arg_s = ", ".join(arg_s_list)
-> [1385](https://file+.vscode-resource.vscode-cdn.net/home/firestar/NAOC/HVC-catalog/Test/~/.miniforge/lib/python3.13/site-packages/traitlets/traitlets.py:1385) warn(
1386 "Passing unrecognized arguments to super({classname}).__init__({arg_s}).\n"
1387 "{error}\n"
1388 "This is deprecated in traitlets 4.2."
1389 "This error will be raised in a future release of traitlets.".format(
1390 arg_s=arg_s,
1391 classname=self.__class__.__name__,
1392 error=e,
1393 ),
1394 DeprecationWarning,
1395 stacklevel=2,
1396 )
File ~/.miniforge/lib/python3.13/site-packages/traitlets/utils/warnings.py:14, in warn(msg, category, stacklevel, source)
9 def warn(msg: str, category: t.Any, *, stacklevel: int, source: t.Any = None) -> None:
10 """Like warnings.warn(), but category and stacklevel are required.
11
12 You pretty much never want the default stacklevel of 1, so this helps
13 encourage setting it explicitly."""
---> [14](https://file+.vscode-resource.vscode-cdn.net/home/firestar/NAOC/HVC-catalog/Test/~/.miniforge/lib/python3.13/site-packages/traitlets/utils/warnings.py:14) warnings.warn(msg, category=category, stacklevel=stacklevel, source=source)
DeprecationWarning: Passing unrecognized arguments to super(Toolbar).__init__().
NavigationToolbar2WebAgg.__init__() missing 1 required positional argument: 'canvas'
This is deprecated in traitlets 4.2.This error will be raised in a future release of traitlets.
Versions
3.13.11 | packaged by conda-forge | (main, Dec 6 2025, 11:24:03) [GCC 14.3.0]
ipympl version: 0.9.8
Selected Jupyter core packages...
IPython : 9.8.0
ipykernel : 7.1.0
ipywidgets : 8.1.8
jupyter_client : 8.7.0
jupyter_core : 5.9.1
jupyter_server : 2.17.0
jupyterlab : not installed
nbclient : 0.10.4
nbconvert : 7.16.6
nbformat : 5.10.4
notebook : not installed
qtconsole : not installed
traitlets : 5.14.3
Activity
Firestar-Reimu-Pro commentedon Dec 26, 2025
I does not know why this problem happen nor can I re-create the problem, this is like ghost
I only know this happen when
fig, ax = plt.subplots(1, 2, figsize=[10, 4])rossjjennings commentedon Jan 22, 2026
I've run into this too and just wasted a couple of hours trying to chase it down, which was very annoying. It would show up a few cells into a big notebook, and then in every plot cell thereafter, but seemingly go away if I tried to start fresh to get a minimal example. But it might just be that the warning is getting suppressed somehow. Using a warnings filter to convert warnings into errors, I get it more reliably. This seems to be sufficient to reproduce it:
Relevant versions for me are:
My understanding of what happens (given the traceback after converting to an error) is that constructing a
Figureeventually callsipympl.backend_nbagg._Backend_ipympl.new_figure_manager_given_figure(), which tries to construct aFigureManager, which in turn tries to construct aToolbar. The constructor foripympl.backend_nbagg.Toolbargets passed acanvasobject, but its base classmatplotlib.backends.backend_webagg_core.NavigationToolbar2WebAggdoesn't get it on the other end.The class
Toolbarinherits from bothipywidgets.widgets.domwidget.DOMWidgetandmatplotlib.backends.backend_webagg_core.NavigationToolbar2WebAgg, giving it a pretty big MRO to dig through:Interesting things seem to be happening in the constructors for:
ipywidgets.widgets.widget.Widget(passes along**kwargsbut not*args, which is where thecanvasobject should be)traitlets.traitlets.HasTraits(This is what gives rise to the warning, which would otherwise be an error. Thecanvasis already gone at this point).rossjjennings commentedon Feb 19, 2026
Update: I eventually figured out that this warning is normally hidden, and the only reason it showed up at all was part of my own code that called
warnings.resetwarnings()after changing the warnings filter. Updating that code to use awith warnings.catch_warnings()block got rid of the warning, but presumably the underlying cause is still there.Firestar-Reimu-Pro commentedon Apr 15, 2026
Why is traitlets 5.14 now but ipympl is still using a pre-4.2 function