[pickers] Fields don't work with AdapterDateFns and zhCN locale

[arjaym-dev]

The problem in depth

Hello, first here's the live demo for the said issues https://stackblitz.com/edit/react-knfbz7?file=Demo.js

Step to reproduce:
First Scenario you must use the enUS as the adaterLocale
PS: the format of field is in this type 'MMM d HH:mm' the step below you must change/update value is the HH:mm for you to see the concern issues

• Then after that try making changes on the SingleInputDateTimeRangeField then look for the logs
• The logs shows [dateValue, dateValue] if you update the firstInputDate
• The logs shows [dateValue, dateValue] if you update the endInputDate

Second Scenario you must change the enUS to zhCN as the adapterLocale

• Then after that try making changes on the SingleInputDateTimeRangeField then look for the logs
• The logs shows [null, dateValue] if you update the firstInputDate
• The logs shows [dateValue, null] if you update the endInputDate

Expected result:
On second scenario if the locale is using zhCN it should not null either value for first or end inputDate. it should be same result with the first scenario

Note: Only the zhCN return null but when using other locale it works perfectly

import { enUS, zhCN, de, enGB } from 'date-fns/locale'

Your environment

`npx @mui/envinfo`

  Don't forget to mention which browser you used.
  Output from `npx @mui/envinfo` goes here.

Search keywords: SingleInputDateTimeRangeField, locale
Order ID: 70493

[michelengelen]

Ok, I did manage to find a reproduction for this.
Apparently putting in any month with a leading 1 is not working (10, 11, 12, and even 1). 10 seems to be the worst as it looks like this will result in an incorrect value which in turn resolves in null.

Screen.Recording.2024-10-02.at.14.40.13.mov

@flaviendelangle you did build the single input field ... could you have a look at this?

[flaviendelangle]

Hey thanks for your detailed example.

The zhCN locale is enable to parse dates with this format when the month is October 😬
The problem seems to be the MMM token (MMMM is also broken), you can try the format MM d which works and MMM d which is broken.

Here a simple reproduction case

This looks like the bug repported in this issue: date-fns/date-fns#3256

I would suggest you to have a look and it and if you have the time to propose a fix.

[arjaym-dev]

After checking out related issues, seems likes on date-fns date-fns/date-fns#3256 that still not able/possible to parse when month is October and any date & locale zhCN. Still now i know what's happening behind why its returning null.

Thank you for that workaround of using MM d format. @flaviendelangle @michelengelen