date: Adds support for datetime for parameter -d

[philolo1]

This resolves issue #5177.

The PR adds a new enum HumanDuration(Duration), HumanDateTime(DateTime) and uses parse_datetime::parse_datetime::from_str to support datetime if relative time cannot be parsed.

For example we can now parse date -d "@0", date -d "1992-02-12" and date -d "2012-01-01 14:00".

Furthermore tests are added for tests/by-util/test_date.rs.

[tertsdiepraam]

Cool! I don't think we need 2 variants. Basically parse_datetime should always return a DateTime. If it parses a relative time, it should add that to the current time.

[philolo1]

@tertsdiepraam thank you for your comment, would you recommend to change parse_datetime so it accepts relative time? I can do that, just want to confirm first.

[tertsdiepraam]

In theory yes, but there's a lot happening there already. Let's start here to get the issue fixed and look at getting that change to parse_datetime later. Does that sound good?

[philolo1]

@tertsdiepraam okay, so you want me to fix the comments by the bot for now only?

[tertsdiepraam]

Hmmm, actually you're right. I didn't think this through. Yes, parse_datetime should do both absolute and relative in one function. Sorry for the confusion :)

[philolo1]

@tertsdiepraam okay no problem. Thanks for clarification.

[tertsdiepraam]

Looks like touch is failing because the new parse_datetime version. I think we could make touch depend on a separate version and then fix that in another PR. cargo deny will complain, but we can temporarily add parse_datetime to the deny.toml list of ignored crates to fix that.

[sylvestre]

No activity for a while, closing!

Feel free to reopen when ready