[DateTimePicker] disablePast is not disabling or validating time

[karinehaug]

• 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 😯

When adding disablePast to DateTimePicker, previous dates are disabled and validations kicks in when typing past date. But the time picker are not disabling past time, and there is no validation to it either.

Expected Behavior 🤔

If current date is selected, past time should also be disabled in picker, and validation/onError should happen when typing past time.

Steps to Reproduce 🕹

https://codesandbox.io/s/datetimepicker-disablepast-qr8re?file=/src/App.tsx

Steps:

1. The first DateTimePicker in the sandbox is displaying the expected validation error on past date
2. The second DateTimePicker is not displaying the expected validation error on past time (except for when visiting the sandbox < 5 minutes past midnight 😅)

Context 🔦

I want to validate that the datetime is not in the past and is not before some other date (so I've already used the minDateTime for that)

Your Environment 🌎

`npx @material-ui/envinfo`

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

[mnajdova]

This is not supported currently. Even the description of the props disablePast and disableFuture states that they are disabling future/past days

I'd say this is low priority, but we could wait for upvotes. What do you think @eps1lon ?

[eps1lon]

disablePast should consider its context. For example, in a DatePicker it should only error if it is given a past day. But in a DateTimePicker it should also error if the hour is in the past.

Right now disablePast only considers days which is confusing. I think it's reasonable to expect that <DateTimePicker disablePast /> considers time and not just date.

The immediate solution is to rename disablePast to disablePastDays but I think long term we do want to error if the time in a DateTimePicker is in the past and disablePast is true.

[flaviendelangle]

I will take care of this issue after #4814 👍