Create Python Environment: show a back button and ability to detect user cancellation

[DonJayamanne]

Is it possible to have a back button on the quick pick displayed for env creation.
This way when users go into kernel picker and choose the ability to create a kernel, then they can go back.

Else today when users hit the cancel button there's no way to know the user hit cancel

Suggestions:'

• When command is called from an extension add support for an argument which would indicate whether a back button is required
• If this new argument is prohibited an user hits the back button then throw a CancellationError (vscode error to notify of the cancellation)
• If the user hits cancel and dismisses the quick pick , then do as previous step

[DonJayamanne]

@brettcannon @karrtikr
Are you happy for me to submit a PR for this.
Would you prefer a new API method or re-use the same command?

[karrtikr]

@karthiknadig owns this component. What do you think?

[brettcannon]

This way when users go into kernel picker and choose the ability to create a kernel, then they can go back.

Else today when users hit the cancel button there's no way to know the user hit cancel

So is the concern more that you are somewhere part way in picking a kernel and you don't know someone dropped out of it? I can see a back button happening when someone realizes they made a mistake, but that won't solve knowing about a cancellation in all cases, correct?

[karthiknadig]

I would like some clarity on the flow. It is a confusing on how back button will be used here.

[DonJayamanne]

@karthiknadig
Please could you install the latest pre-release of Jupyter and Python extension in vsocode insiders

• Then add the following setting into your user settings file

"notebook.kernelPicker.type": "mru",

• Open a new empty workspace folder
• Create a new ipynb file
• Go into the kernel picker,. and select Python Environment and use the option to create a new python env
  That will take you to the Python Quick pick to create a Python env (venv or conda), however one you get there
  there's no way to cancel that and go back to the original kernel picker UI
  We would like the whole workflow to be a smooth process so that users have the ability to go back (e.g. they might not want to create a venv or the like).

[brettcannon]

• Then add the following setting into your user settings file

Which settings are you referring to?

[DonJayamanne]

Oops, updated

[DonJayamanne]

@karthiknadig do you have an update on this?

[karthiknadig]

@DonJayamanne This won't make it in the current iteration. We have two public APIs that we need to update with this change. Since we will be exposing this to other extensions we want to make sure that the back support is generic enough to work for the scenarios intended with the API.

[karthiknadig]

@karrtikr We will need to discuss changes to environment selector and its API.

[DonJayamanne]

@brettcannon @karthiknadig

Please could we also get the following feature:

• Notify caller when user hits the cancel button during any stage of the Creationg (e.g. esc key in the quick pick)

This is requires so that we know the user cancelled the env creation, else we do not know this and could end up re-displaying the same quick pick or other quick picks in the Jupyter extension

Throwing the vscode.Cancellation error would work (as this would indicate that the flow has been cancelled by the user)
Note: This is the same error VS Code uses for such workflow related tasks.

[DonJayamanne]

@karthiknadig Just wanted to check if there was any update on this or whether you could provide some guidance on what this API would look like. thanks

[karthiknadig]

The command for this will have an optional field that takes showBackButton, with that field set, when user hits back or cancel (keyboard escape) we will raise an exception indicating if it was Back or Cancel.

[DonJayamanne]

Thanks, however we will need to differentiate between cancel and back
As cancel means dismiss the whole workflow
And back means go back to the previous quickpick

[karthiknadig]

Yes, "Back" and "Cancel" represent distinct user actions and therefore the API will represent them as separate exceptions.

[karthiknadig]

Minor change to the above description, the action for the command will be returned using a field. We will provide a proper extension API for this, the solution below is a stop gap till then. Below is how you can get the UI to show back button, and action field to see what action was taken.

let result: CreateEnvironmentResult | undefined;
try {
    const result = await commands.executeCommand("python.createEnvironment", {showBackButton: true});
} catch(e) {
   // error while creating environment
}

if (result?.action === 'Back') {
    // user clicked Back
}

if (result?.action === 'Cancel') {
    // user pressed escape or Cancel
}