bug#37130: 27.0.50; Tar mode should use the ISO8601 format to display the timestamps (or support TIME_STYLE or locales)

bug#37130: 27.0.50; Tar mode should use the ISO8601 format to display the timestamps (or support TIME_STYLE or locales)

[Vincent Lefevre]

When tar-mode-show-date is set to t (to get the timestamps), the
Tar mode displays them in a non-standard format. It should use
the ISO8601 format (this is what GNU tar does). Other formats
(e.g. one corresponding to the locales) could be used via an option;
in particular, the support of the TIME_STYLE environment variable
(see coreutils manual) would be a good idea.


In GNU Emacs 27.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.10)
 of 2019-08-20 built on cventin
Repository revision: 50dc4ca8d02a466a7236765edf83ae7cfb02d74c
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12004000
System Description: Debian GNU/Linux bullseye/sid

Recent messages:
Loading /home/vlefevre/share/emacs/site-lisp/mutteditor.el (source)...done
Loading time...done
For information about GNU Emacs and the GNU system, type C-h C-a.
Making completion list...

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bug#37130: 27.0.50; Tar mode should use the ISO8601 format to display the timestamps (or support TIME_STYLE or locales)

[Lars Ingebrigtsen]

Vincent Lefevre <vincent@vinc17.net> writes:

> When tar-mode-show-date is set to t (to get the timestamps), the
> Tar mode displays them in a non-standard format. It should use
> the ISO8601 format (this is what GNU tar does).

I think it makes sense to follow GNU tar's lead here, so I've now done
this on the trunk.

> Other formats (e.g. one corresponding to the locales) could be used
> via an option; in particular, the support of the TIME_STYLE
> environment variable (see coreutils manual) would be a good idea.

I think that sounds like overkill for tar-mode, but perhaps there should
be a general function somewhere for using TIME_STYLE throughout Emacs
whenever time/dates are displayed.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#37130: 27.0.50; Tar mode should use the ISO8601 format to display the timestamps (or support TIME_STYLE or locales)

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@mouse.gnus.org>
> Date: Fri, 23 Aug 2019 05:46:26 +0200
> Cc: 37130@debbugs.gnu.org
> 
> Vincent Lefevre <vincent@vinc17.net> writes:
> 
> > When tar-mode-show-date is set to t (to get the timestamps), the
> > Tar mode displays them in a non-standard format. It should use
> > the ISO8601 format (this is what GNU tar does).
> 
> I think it makes sense to follow GNU tar's lead here, so I've now done
> this on the trunk.

Yuck! what an ugly format!

> > Other formats (e.g. one corresponding to the locales) could be used
> > via an option; in particular, the support of the TIME_STYLE
> > environment variable (see coreutils manual) would be a good idea.
> 
> I think that sounds like overkill for tar-mode, but perhaps there should
> be a general function somewhere for using TIME_STYLE throughout Emacs
> whenever time/dates are displayed.

I think we should just make the format used for the time stamp a user
option, that would be a good-enough solution.  It will also provide a
"fire escape" to get the old behavior for those, like me, who might
dislike the ISO8601 format.  We must provide such
backward-compatibility options anyway when we change behavior in
incompatible ways.

Finally, this change should be in NEWS (including the to-be-added
backward-compatibility shim).

Thanks.

bug#37130: 27.0.50; Tar mode should use the ISO8601 format to display the timestamps (or support TIME_STYLE or locales)

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

>> I think it makes sense to follow GNU tar's lead here, so I've now done
>> this on the trunk.
>
> Yuck! what an ugly format!

Yes, I didn't check what GNU tar really did, so I just put in ISO8601.
I've now checked and replicated the format, which looks nicer.

>> > Other formats (e.g. one corresponding to the locales) could be used
>> > via an option; in particular, the support of the TIME_STYLE
>> > environment variable (see coreutils manual) would be a good idea.
>> 
>> I think that sounds like overkill for tar-mode, but perhaps there should
>> be a general function somewhere for using TIME_STYLE throughout Emacs
>> whenever time/dates are displayed.
>
> I think we should just make the format used for the time stamp a user
> option, that would be a good-enough solution.  It will also provide a
> "fire escape" to get the old behavior for those, like me, who might
> dislike the ISO8601 format.  We must provide such
> backward-compatibility options anyway when we change behavior in
> incompatible ways.

We don't, in general, add such options unless we think it's going to be
used a lot.  For tar mode, my feeling is that nobody will ever care
enough to bother to customise it.

> Finally, this change should be in NEWS (including the to-be-added
> backward-compatibility shim).

Or even notice it, which is why I didn't mention it in NEWS.  It seem
like a not particularly NEWS-worthy item to me.

If you think this really warrants a user customisation and a NEWS item,
I'd rather just revert the change and mark this bug as a WONTFIX,
because it doesn't seem like that to me.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#37130: 27.0.50; Tar mode should use the ISO8601 format to display the timestamps (or support TIME_STYLE or locales)

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: 37130@debbugs.gnu.org,  vincent@vinc17.net
> Date: Sun, 25 Aug 2019 08:03:21 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> I think it makes sense to follow GNU tar's lead here, so I've now done
> >> this on the trunk.
> >
> > Yuck! what an ugly format!
> 
> Yes, I didn't check what GNU tar really did, so I just put in ISO8601.
> I've now checked and replicated the format, which looks nicer.

Yes, much nicer, thanks.

> > Finally, this change should be in NEWS (including the to-be-added
> > backward-compatibility shim).
> 
> Or even notice it, which is why I didn't mention it in NEWS.  It seem
> like a not particularly NEWS-worthy item to me.

Maybe not with the change as it is now.  It was a big change
originally.