[Autocomplete] prevent highlight index from resetting when options are added

[cjtroiano]

fix #29508

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[mui-bot]

Details of bundle changes

Generated by 🚫 dangerJS against 63e8baa

[cjtroiano]

I wasn't 100% on what to do with this.

This exact function exists in TreeView, but isn't exported.
We also have usePreviousProps in the utils package.

[michaldudak]

Please use the usePreviousProps from the utils package.

[oliviertassinari]

It's not clear to me if this is not a regression. Some might expect that new options = a reset of the highlight.

[cjtroiano]

Are you suggesting that we allow the highlight index to reset, but prevent scroll to top?

[michaldudak]

@oliviertassinari seeing the number of issues reported about this, the community seems to have a different view on this. It may be confusing to have highlight gone when data is loaded on demand.

@cjtroiano I'm wondering about another scenario that your PR doesn't cover - what if the number of items decreased, but the highlighted item is still among them. IMO we should keep the highlight there as well:

it('should keep focus on selected option and not reset to top option when options updated', () => {
  const { setProps } = render(
    <Autocomplete
      open
      options={['one', 'two', 'three']}
      renderInput={(params) => <TextField {...params} autoFocus />}
    />,
  );
  const textbox = screen.getByRole('combobox');
  const listbox = screen.getByRole('listbox');

  fireEvent.keyDown(textbox, { key: 'ArrowDown' }); // goes to 'one'
  fireEvent.keyDown(textbox, { key: 'ArrowDown' }); // goes to 'two'

  checkHighlightIs(listbox, 'two');

  // three option is added and autocomplete re-renders, do not reset the highlight
  setProps({ options: ['two', 'three'] });
  checkHighlightIs(listbox, 'two');
});

[justintoman]

Any movement on this? I'd be happy to try to help!

Maybe instead of always resetting or never resetting, it could reset only if the previously highlighted option no longer exists. If it still exists, it can remain highlighted. If it no longer exists, then we reset.

[jimmycallin]

I would also be very happy if this got prioritized, let me know if I can help somehow!

[michaldudak]

@justintoman, @jimmycallin, feel free to give it a stab (just decide between the two of you who'll do it).

Maybe instead of always resetting or never resetting, it could reset only if the previously highlighted option no longer exists. If it still exists, it can remain highlighted. If it no longer exists, then we reset.

I think this should be the way to go. Let's implement this and see how it behaves live.

[ZeeshanTamboli]

Since there is no activity in this PR, I am closing it in favour of #35735.