Jupyter Extension cannot use Proposed API in Stable VS Code

[DonJayamanne]

• VS Code Version: 1.54
• OS Version: N/A

Steps to Reproduce:

1. Install Jupyter Extension
2. Add the following into your settings

"jupyter.experiments.optInto": ["__NativeNotebookEditor__"],

3. Extension fails to load

@rebornix /cc

Does this issue occur when all extensions are disabled?: Yes/No

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• Jupyter Notebooks (#117520)

[kajuberdut]

The error does come up when extensions are disabled, but importantly, it also breaks the python extension on stable when no jupyter experiments config line is present. Is there a workaround other than somehow forcing a rollback of the Feb update?

This broke immediately after the Feb update for me (Windows 10 Pro, VS Code 1.54.0, jupyter v2021.3.619093157) I have never installed anything related to jupyter except the extension (and only because it's required by the Python extension.)

[DonJayamanne]

@sbatten @rebornix @Tyriar Thanks for fixing this quickly and unblocking our users.
& thanks to the rest of the code team.