[4.0.0-alpha.2]: MUI warning when using AutocompleteInput

[wattroll]

What you were expecting:
Use AutocompleteInput without warnings.

What happened instead:

Warning in the console

MUI: The value provided to Autocomplete is invalid. None of the options match with `""`. You can use the `isOptionEqualToValue` prop to customize the equality test.

Note the "", probably that's the offending part.

Steps to reproduce:
Seems to appear in pretty much any AutocompleteInput. Can be seen at posters galore demo, e.g. by going to Orders resource and adding a Customer filter.

---

I bisected it down to this commit:

7de027dce7c3dff1fa11ca1210dfc7f7083b8858 is the first bad commit
commit 7de027dce7c3dff1fa11ca1210dfc7f7083b8858
Author: Travis CI <travis@travis-ci.org>
Date:   Wed Dec 15 14:44:42 2021 +0100

    Merge both autocomplete

I haven't managed to spot the cause of a problem by a quick look-through. @djhi, would you have time to have a look at this? 🙏

[WiXSL]

I couldn't reproduce the error you describe in the demo.
Could you provide a code sandbox or a repo to reproduce it?

[wattroll]

Thanks for having a look at it, and sorry for an incomplete bug report.

I tried, but haven't yet managed to setup a codesandbox against next. I'll get back to it soon

In the meanwhile I made sure that I can reproduce locally in a demo with a fresh checkout:

1. git clone 'https://github.com/marmelab/react-admin.git'
2. cd react-admin/
3. git checkout next
4. make build
5. make run-demo
6. Open http://localhost:3000/#/commands
7. Click "Add filter" > "Customer"

[WiXSL]

Ok, now I could reproduce it.
Thank you for the details.
We're going to look into it.

[WiXSL]

Fixed by #7098