Python: Prompt user to install ipykernel if missing on starting Python

[petetronic]

We rely on ipykernel for the Console (and related Env Pane, Plots Pane etc). Prompt the user to instal this module if we detect it is not installed on stating Python.

[jmcphers]

In my testing, I didn't get prompted for ipykernel, just got an error when I tried to use a Python kernel without it:

[seeM]

This should be slightly better in that it will:

1. Prompt every time you try to start an interpreter without ipykernel
2. Show an error in the Console if you decline the prompt or if the install fails
3. Show a progress indicator while it's installing – with a cancel button if it takes too long (pressing cancel shows the error from 2)

Future points of improvement:

1. Consider using our own custom pop-up instead of VSCode's
2. Replace the error message with a better UI component

[petetronic]

Thanks Wasim, let's file a separate issue for using a modal dialog instead of the easy-to-dismiss message that the extension uses now. I tried switching between different python versions that did not include the ipykernel module and was prompted to install them.

[seeM]

Great. Closing this. Here's the new issue:

• Python: Use a modal dialog component when prompting to install ipykernel #717