Re: [PATCH v2 5/6] date: document and test "raw-local" mode

From: Jeff King <peff@peff.net>
Date: Jul 26, 2016, 18:47 UTC
Message-ID: <20160726184746.GA678@sigill.intra.peff.net>
In-Reply-To: <579343C9.1040902@gmail.com>

On Sat, Jul 23, 2016 at 12:15:37PM +0200, Jakub Narębski wrote:

Show 21 quoted lines

> > diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
> > index 5d1de06..3ec75d4 100644
> > --- a/Documentation/rev-list-options.txt
> > +++ b/Documentation/rev-list-options.txt
> > @@ -725,8 +725,8 @@ include::pretty-options.txt[]
> >  	`iso-local`), the user's local time zone is used instead.
> >  +
> >  `--date=relative` shows dates relative to the current time,
> > -e.g. ``2 hours ago''. The `-local` option cannot be used with
> > -`--raw` or `--relative`.
> > +e.g. ``2 hours ago''. The `-local` option has no effect for
> > +`--relative`.
> 
> Do I understand it correctly: --relative is a short form for more
> generic --date=relative (which probably should be spelled 
> --date-format=relative), and that --date=relative-local is the
> same as --date=relative, that is *-local suffix does not change
> how date is formatted?
> 
> Because I don't think you can say --relative-local ("The `-local`
> option has no effect on `--relative`"), can you?

All correct. There is no --relative-local because "--relative" is a historical artifact. We could support --foo for every --date=foo, but I don't think there is a reason to do so (and reasons not to, like avoiding cluttering the option space).

Show 7 quoted lines

> > -`--date=raw` shows the date in the internal raw Git format `%s %z` format.
> > +`--date=raw` shows the date in the internal raw Git format `%s %z`
> > +format. Note that the `-local` option does not affect the
> > +seconds-since-epoch value (which is always measured in UTC), but does
> > +switch the accompanying timezone value.
> 
> Which is correct, logical, and next to useless, I think.

This was discussed in the earlier review. It's basically only useful if you are feeding the output to another script which will format the date and want to change what that script shows.

Show 10 quoted lines

> BTW. one kind of format that Git does not support (I think) is the
> varying kind, where the precision changes with the distance from now,
> so that we can get most precision in limited width.  That's what
> `ls --long` does:
> 
>  * 'Jun 29 16:47' for dates falling in current year (more precision)
>  * 'Nov 23  2015' for dates outside (less precision, same width)
> 
> Many other programs switch from relative to absolute time when date
> in question is far in the past that relative is not very good.

Yes, this was discussed on the list not too long ago. I think it would be useful, but is obviously orthogonal to this series.

-Peff