[select] fix: mark items arrays as readonly where appropriate

[maclockard]

Fixes #4976

Checklist

• Includes tests
• Update documentation

Changes proposed in this pull request:

Added readonly annotations to select array props

Reviewers should focus on:

The types

Screenshot

[adidahiya]

I have to revert this, it's causing downstream compilation errors:

[error] TypeScript error packages/[redacted]/filterable-select.tsx:25:9 - error TS2345: Argument of type 'readonly T[]' is not assignable to parameter of type 'T[]'.
  The type 'readonly T[]' is 'readonly' and cannot be assigned to the mutable type 'T[]'.

25         items,
           ~~~~~

[maclockard]

@adidahiya curious if that's actually coming from using a Select/QueryList/etc component or if its coming from downstream consumer reusing IListItemsProps/ISelectProps/etc for their own components?

I suspect it's probably the second looking at the file name. If that's the case, seems easy enough to only apply the change for types blueprint components use, and leave the exported types alone?

[adidahiya]

It is the latter, "downstream consumer reusing ISelectProps for their own components". I'm open to an alternative fix if you want to send a PR. I'll test it downstream before merging.

[maclockard]

hmmm, now that I think about it, my potential solution to that problem kinda falls under 'no one wins' territory since folks trying to get the actual prop types will have trouble.

I think it makes sense to do this as a breaking change as a part of v5. That way we could also fix the callback types as well. What does queuing a change for v5 look like?

[adidahiya]

What does queuing a change for v5 look like?

I'm not ready for this yet, but i'll have a process for this ready in the next few weeks. Stay tuned