[Autocomplete] autoHighlight doesn't highlight on keypress following a "clear"

[aisamu]

• The issue is present in the latest release.
• I have searched the issues of this repository and believe that this is not a duplicate.

Current Behavior 😯

autoHighlight doesn't highlight the first item after clearing the query (either via mouse or keyboard):

Clearing with the mouse

Clearing with the Keyboard

Expected Behavior 🤔

First item should be highlighted

Steps to Reproduce 🕹

Steps:

1. Visit https://codesandbox.io/s/material-demo-hubij (First example of the demo page with autoHighlight enabled)
2. Click on the component to open the drop-down
3. Type a query, clear it (esc or ✖️), then proceed with the query

Your Environment 🌎

Whatever's being currently used for the demo page!
We've double checked that it also happens on our environment:

Tech	Version
@material-ui/core	4.7.2 & 4.8.3
@material-ui/lab	4.0.0-alpha.38 & alpha.39
React	16.12.0
Browser	Safari 13 (❌), Chrome 79 (❌) , Firefox 72(❌)

[oliviertassinari]

@aisamu Thanks for opening this issue. I can reproduce the issue. The reproduction seems simple:

• focus the input
• close the popup
• type one matching letter

The problem is that we try to reset the highlighted index but the listboxRef isn't open yet.
It's a duplicate of #18646. The solution proposed their solve this problem too.
It took me a bit of time to figure it out. The component is quite complex. I had forgotten about this point. If you are interested, you can submit a pull request. The main missing part is that we need is regression tests. It seems that they are 3 broken cases, so 3 new tests?

[aisamu]

Just to be sure: when you say it's a duplicate you're referring to the root cause, right? (the linked issue mentions freeSolo and autoSelect set to true)

The component is quite complex [...] you can submit a pull request.

This might be unfortunately beyond my current JS-fu.
You see, I'm still struggling trying to apply the patch from #19213 😄

In any case, I'll surely try to allocate some time (and perhaps pester some knowledgeable coworkers)

Thanks for following up!

[oliviertassinari]

@aisamu No pain, no gain 🙃.

You have found 3 nice issues with the Autocomplete component. I have proposed 3 solutions. If you don't have the time to look into them. It's fine, if they are important enough, a third developer might come in and carry the resolution down to a stable release. We really appreciate the quality of your bug reports, especially 3 in a row.

[aisamu]

@aisamu No pain, no gain 🙃.

1 out of 3! With some faith the other two might eventually arrive as well

We really appreciate the quality of your bug reports, especially 3 in a row.

Given our lack of skills to solve it ourselves, it's really the very least we could do :)