fix bug: check before using the variables

[ya0guang]

No description provided.

[welcome]

Thanks for submitting your first pull request! You are awesome! 🤗

If you haven't done so already, check out Jupyter's Code of Conduct. Also, please make sure you followed the pull request template, as this will help us review your contribution more quickly.

You can meet the other Jovyans by joining our Discourse forum. There is also a intro thread there where you can stop by and say Hi! 👋

Welcome to the Jupyter community! 🎉

[krassowski]

Thank you! Makes sense to me, probably worth adding a test for it though.

[dlqqq]

@ya0guang Nice catch, thank you! 💪

[welcome]

Congrats on your first merged pull request in this project! 🎉

Thank you for contributing, we are very proud of you! ❤️

[dlqqq]

@meeseeksdev please backport to 1.x

[lumberbot-app]

Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

git checkout 1.x
git pull

2. Cherry pick the first parent branch of the this PR on top of the older branch:

git cherry-pick -x -m1 0ae649e61fbb8763377a65d244372c5d6dbba41f

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

git commit -am 'Backport PR #656: fix bug: check before using the variables'

4. Push to a named branch:

git push YOURFORK 1.x:auto-backport-of-pr-656-on-1.x

5. Create a PR against branch 1.x, I would have named this PR:

"Backport PR #656 on branch 1.x (fix bug: check before using the variables)"

And apply the correct labels and milestones.

Congratulations — you did some good work! Hopefully your backport PR will be tested by the continuous integration and merged soon!

Remember to remove the Still Needs Manual Backport label once the PR gets merged.

If these instructions are inaccurate, feel free to suggest an improvement.

[dlqqq]

Oh wait NVM, this corrects the implementation of the inline completer, exclusive to main. This PR should not be backported to 1.x.