Can't add keyboard shortcuts to actions of extension

[shingo78]

We are developing https://github.com/NII-cloud-operation/Jupyter-multi_outputs

I can't add a keyboard shortcut to actions of this extension using Edit keyboard shortcuts.
The added keyboard shortcuts are enabled before reloading the notebook, but disabled with the following error after reloading.

Uncaught (in promise) Error: does not know how to deal with : MultiOutputs:pin_output
    at ShortcutManager.add_shortcut (keyboard.js:457)
    at ShortcutManager.add_shortcuts (keyboard.js:475)
    at keyboardmanager.js:80
    at <anonymous>

Reproduction procedure:

1. Select the Edit keyboard Shortcuts menu item
2. Add a shortcut to the action of multi_outputs extension, click OK button
3. Reload the notebook

This MultiOutputs:pin_output action is registered by the multi_outputs extension.
https://github.com/NII-cloud-operation/Jupyter-multi_outputs/blob/master/lc_multi_outputs/nbextension/main.js#L604-L608

Could you give me some advice?

[takluyver]

I guess there's a race condition, that it's trying to add the shortcut before the extension has loaded and defined the action. It's a tricky one; it should be possible to bind a shortcut to an action name that hasn't been registered yet, but it's also nice to be able to catch incorrect action names.

Maybe add_shortcut could have an extra parameter to allow it to bind to actions which aren't registered yet. @Carreau @gnestor ?

[Carreau]

Maybe add_shortcut could have an extra parameter to allow it to bind to actions which aren't registered yet. @Carreau @gnestor ?

I though it was already the case by default; I'll have to re-check.
Though I think that might be because of Edit shortcuts, I believe Edit is more complicated (as it may interfere with Codemirror); so was not completely implemented.

[gnestor]

The issue is that the actions and keyboard_manager objects are created before extensions are loaded. This is for good reason because otherwise the notebook could take a long time to load.

The simple solution is to move all the actions/keyboard manager creation stuff into the .then after extensions are loaded. Unfortunately, almost all of the main objects depend on actions or keyboard manager, including the notebook, so that wouldn't buy us much.

Another approach woulds be to break out the adding of config shortcuts (vs. default shortcuts) to a new method on keyboard manager that could be called after extensions are loaded.