Not working in JupyterLab or Visual Studio Code (only in hosted Jupyter Notebook) about ipython_blocking

[kafonek]

@opoloko thanks for flagging this, I haven't done any extensive testing with JupyterLab or VSCode. After a bit of cursory fiddling this evening, I'm leaning towards the issue being with magic commands (%block, %blockrun) working differently in JupyterLab / VSCode versus classic Notebook.

I was able to get this minimal example to work with expected behavior in Jupyterlab:

### cell 1
import ipywidgets as widgets

dropdown = widgets.Dropdown(options=['', 'foo', 'bar', 'baz'])
dropdown

### cell 2
import ipython_blocking
ctx = ipython_blocking.CaptureExecution()
with ctx:     
    while True:
        if dropdown.value:
            break
        ctx.step()

### cell 3
print("just a string to demonstrate blocking until dropdown changes")

### cell 4
print(dropdown.value)

After a cell -> run all, cells 3 and 4 didn't execute until after I chose an option in the dropdown widget.

I haven't spent a lot of time looking at IPython magic commands outside of classic Notebook. If you have any leads on the differences between classic vs Lab/VSCode, I'd appreciate pointers. Thanks.

[bryceschober]

Me too, FWIW...

[kafonek]

@bryceschober I'm afraid I'm having trouble replicating these errors. I just ran the 4-cell example code in both a VSCode (centos7 / python 3.6 / VSCode Python extension) and JupyterLab (Lab 2.2.5, using docker-stacks image, installed @jupyter-widgets from extension manager).

Can you give any more details about system or versions that aren't working for you? Thanks.

[bryceschober]

@kafonek Hey, I guess you're right. I must have been doing something else wrong, because I switched a separate notebook to %block dropdown and it does work... You can go ahead and close this case.