Avoid using the `ipywidgets.Output` widget

[yakutovicha]

The widget behaves quite unpredictably. For versions of ipywidgets, it fails to show
the content and prevents other widgets from being displayed.

[danielhollas]

For versions of ipywidgets,

@yakutovicha can you clarify for which ipywidgets versions have you observed this? Even for 8.x? Supposedly it works well enough with 7.7?

[yakutovicha]

For versions of ipywidgets,

@yakutovicha can you clarify for which ipywidgets versions have you observed this? Even for 8.x?

I am not sure, but we've had enough issues in the past; this is more of a precaution. Moreover, it is not clear to me if the issue was the ipywidgets themselves or some of their dependencies (e.g. widgetsnbextension)

Supposedly it works well enough with 7.7?

No, it is not. We had observed weird behaviour of ipw.Output in the past as well. You can look it up here aiidalab/aiidalab-home#185.

My practical approach here would be to replace things with ipw.VBox, which has always worked, rather than trying to understand the particular version combination that caused (or did not cause) the problem.

It also has an additional advantage that ipw.VBox embeds seamlessly in the widget infrastructure, while ipw.Output is a bit of an "outsider".

[danielhollas]

Agreed the removing ipywidgets.Output widgets would be beneficial. The only question here is whether this needs to block v3 release, or whether we can postpone (as long as the widgets work as they are, which we should verify)

There are currently 8 instances of the Output widget:

❯ git grep -n -C2 'Output('
aiidalab_widgets_base/computational_resources.py-113-            selection_row.children += (self.btn_setup_new_code,)
aiidalab_widgets_base/computational_resources.py-114-
aiidalab_widgets_base/computational_resources.py:115:            self._setup_new_code_output = ipw.Output(
aiidalab_widgets_base/computational_resources.py-116-                layout={"width": self._output_width}
aiidalab_widgets_base/computational_resources.py-117-            )
--
aiidalab_widgets_base/computational_resources.py-352-            self._on_verification_mode_change, names="value"
aiidalab_widgets_base/computational_resources.py-353-        )
aiidalab_widgets_base/computational_resources.py:354:        self._verification_mode_output = ipw.Output()
aiidalab_widgets_base/computational_resources.py-355-
aiidalab_widgets_base/computational_resources.py-356-        self._continue_button = ipw.ToggleButton(
--
aiidalab_widgets_base/computational_resources.py-1154-        btn_setup_code = ipw.Button(description="Setup code")
aiidalab_widgets_base/computational_resources.py-1155-        btn_setup_code.on_click(self.on_setup_code)
aiidalab_widgets_base/computational_resources.py:1156:        self.setup_code_out = ipw.Output()
aiidalab_widgets_base/computational_resources.py-1157-
aiidalab_widgets_base/computational_resources.py-1158-        children = [
--
aiidalab_widgets_base/elns.py-69-    def __init__(self, path_to_root="../", **kwargs):
aiidalab_widgets_base/elns.py-70-        # Used to output additional settings.
aiidalab_widgets_base/elns.py:71:        self._output = ipw.Output()
aiidalab_widgets_base/elns.py-72-
aiidalab_widgets_base/elns.py-73-        # Communicate to the user if something isn't right.
--
aiidalab_widgets_base/elns.py-102-
aiidalab_widgets_base/elns.py-103-        # Used to output additional settings.
aiidalab_widgets_base/elns.py:104:        self._output = ipw.Output()
aiidalab_widgets_base/elns.py-105-
aiidalab_widgets_base/elns.py-106-        # Communicate to the user if something isn't right.
--
aiidalab_widgets_base/elns.py-170-class ElnConfigureWidget(ipw.VBox):
aiidalab_widgets_base/elns.py-171-    def __init__(self, **kwargs):
aiidalab_widgets_base/elns.py:172:        self._output = ipw.Output()
aiidalab_widgets_base/elns.py-173-        self.eln = None
aiidalab_widgets_base/elns.py-174-
--
aiidalab_widgets_base/viewers.py-69-
aiidalab_widgets_base/viewers.py-70-    def __init__(self, **kwargs):
aiidalab_widgets_base/viewers.py:71:        self._output = ipw.Output()
aiidalab_widgets_base/viewers.py-72-        self.node_views = {}
aiidalab_widgets_base/viewers.py-73-        self.node_view_loading_message = LoadingWidget("Loading node view")
--
aiidalab_widgets_base/viewers.py-1637-
aiidalab_widgets_base/viewers.py-1638-        output_notebook(hide_banner=True)
aiidalab_widgets_base/viewers.py:1639:        out = ipw.Output()
aiidalab_widgets_base/viewers.py-1640-        with out:
aiidalab_widgets_base/viewers.py-1641-            plot_info = bands._get_bandplot_data(cartesian=True, join_symbol="|")