Based on conversations on July 9, we're going to stick with the existing MediaSearch autocomplete backend for this ticket, which will just focus on the UI.

We recognize that the existing MediaSearch autocomplete backend has a lot of room for improvement, but that we need to do more exploration to figure out how to do that and it will be handed in future tickets.

Change 617796 had a related patch set uploaded (by Anne Tomasevich; owner: Anne Tomasevich):
[mediawiki/extensions/WikibaseMediaInfo@master] Recreate autocomplete search input

https://gerrit.wikimedia.org/r/617796

Change 617796 merged by jenkins-bot:
[mediawiki/extensions/WikibaseMediaInfo@master] Recreate autocomplete search input

https://gerrit.wikimedia.org/r/617796

@Etonkovidova FYI this is broken on production and should be fixed by https://gerrit.wikimedia.org/r/c/mediawiki/extensions/WikibaseMediaInfo/+/621353

Checked on commons wmf.6 - the autocomplete is present.

Some issues were found:
(1) There is a delay (sort of) in changing the autocomplete, e.g.

• start typing 'Foun', then delete the entry with the backspace and type 'Lion' - the suggestions won't chage.
  
• when 'Lion' is deleted, the autocomplete changes to show to the autocomplete for 'L':

The ssues mentioned in T252891: Improve autocomplete for mediasearch on commons are still there, i.e.

• the autocomplete for a mediasearch that will give no results
• the issues with CJK languages mentioned in TJones's comment on T252891
• the issues that are in my comment on T252891

T252891 has good test/use cases (I've added the info to my testing list) which were not resolved with vue.js version of Media Search UI.
@CBogen - should be there one (epic-like) task with subtasks to address various autocomplete issues or there is another way for keeping track on autocomplete improvements?

@Etonkovidova thanks for reporting these. I think that the delay issue should be fixed as part of this ticket (unless you'd rather have a new ticket, @AnneT).

For the other issues you mentioned in T252891, I think it's best to file them as new tickets. I don't think we need an epic to track them. We can assign them to the Media Search Release Candidate milestone. Some of them may be addressed by the work the Search team is doing on Query Completion, which is currently waiting for legal review (T250436), but I'm not sure. The issues with CJK languages mentioned will hopefully be addressed by Query Completion as well.