output widget append_display_data does not display widgets

[jasongrout]

It seems there are some problems either with the output widget append_display_data method (from #1752), or how we display widgets.

from ipywidgets import Output, IntSlider
out = Output(layout={'border': '1px solid black'})
out.append_display_data(IntSlider())
out

should capture the intslider inside of the output widget, but instead we get

If I use the output widget as a context manager, it works fine:

from ipywidgets import Output, IntSlider
from IPython.display import display
out = Output(layout={'border': '1px solid black'})
with out:
    display(IntSlider())
out

[jasongrout]

From the docs http://ipython.readthedocs.io/en/stable/api/generated/IPython.core.formatters.html:

Prior to IPython 6.1, _ipython_display_ was the only way to display custom mime-types without registering a new Formatter.
IPython 6.1 introduces _repr_mimebundle_ for displaying custom mime-types, so _ipython_display_ should only be used for objects that require unusual display patterns, such as multiple display calls.

We use _ipython_display_, in which we manually call display to display a widget. When we switch to using _repr_mimebundle, I think this issue will resolve itself.

[jasongrout]

IPython 6.1 was released 31 May 2017. I think it will be a while before we can mandate IPython 6.1+ (likely not until ipywidgets 8), so we may just have to live with this for now.

[jasongrout]

actually, we may be able to register a display using the for_type mechanism instead, until we can move to a simple _repr_mimebundle_: http://ipython.readthedocs.io/en/stable/api/generated/IPython.core.formatters.html#IPython.core.formatters.BaseFormatter.for_type

[GaiYu0]

Hi, I am experiencing a similar problem. In my case, the slider widget is displayed properly but the output widget cannot be displayed. Is there any temporary solution?

Thank you very much!

[jasongrout]

@GaiYu0, can you post the code you are using?

[GaiYu0]

It turns out that my problem was caused by broken dependencies, which is irrelevant from this issue. Sorry!