Make `mention_name` optional

[jtpio]

Description

#242 changed mention_name to be required, while it used to be optional in 0.14.0:

jupyter-chat/packages/jupyter-chat/src/types.ts

Line 24 in e6b486b

mention_name: string;

Unfortunately didn't have the chance to review the PR before it got merged, but left a comment in #242 (review).

There are use cases of the chat where mention_name is not required.

Reproduce

Use @jupyter/chat 0.15.0 in a project in a downstream project.

Expected behavior

mention_name should stay optional.

Context

Jupyter Chat 0.15.0.

[jtpio]

@dlqqq would you be able to look into this and make mention_name optional like it was before? Thanks!

[brichet]

@dlqqq after a quick look at the changes in #242, I don't feel like this change was required.
I can build successfully the extension with this field optional (and everything seems to work), so I wonder if you observed some errors at runtime, or issues with jupyter-ai.

[dlqqq]

@jtpio @brichet Sure, but can we also explore allowing potentially unused fields to let Jupyter Chat serve as a foundation for both of our applications? There are some features in Jupyter Chat that aren't required in Jupyter AI, but we are OK with allowing them. It would be nice if we could keep mention_name required for type safety, but leaving its usage optional.

[dlqqq]

This change would make mention_name optional in the frontend model & required in the backend model; that gap could cause inconsistencies/bugs in the future.

[ellisonbg]

@jtpio thanks for calling this out, I have a look to understand the details before commenting more.

[ellisonbg]

@dlqqq are there some things that will break if it is optional?

[dlqqq]

@ellisonbg No, the PR I opened only "loosens" the type & doesn't affect the compiled JavaScript. The risk is that future changes could break this since we no longer enforce a build-time guarantee that user.mention_name is always defined.

The PR now emits a console warning & ignores the user if user.mention_name is not defined.