Re: [RFC PATCH 0/1] adding user.hideTimezone for setting UTC timezone

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Oct 1, 2020, 03:43 UTC
Message-ID: <20201001034350.GB2930867@google.com>
In-Reply-To: <xmqqtuved70y.fsf@gitster.c.googlers.com>

Junio C Hamano wrote:

Show 7 quoted lines

>                                                Our setenv() may not
> be early enough---before the code that decides to call a setenv()
> is run, there are many things that are outside your control (like
> the tracing subsystem, repository discovery, etc.) will run, and if
> any of them does something that triggers tzset() to be called, it
> will be done with the value of TZ the process started with, and our
> setenv() that happens much later won't have any effect to it.

I thought about this before, but in fact it's okay: when calling a function like localtime() (though not localetime_r() --- see my other reply), tzset() is called each time so it is able to reflect any updates to the TZ envvar from the interim.

[....]

Show 8 quoted lines

> You can let the existing code produce its natural result and then
> when the "force UTC" flag is set, override the offset part to +0000
> if and only if the timezone was obtained from the current
> environment (this if-and-only-if is necessary, because you do not
> want to rewrite and force UTC when you run "git commit --amend"
> without the "--reset-author" option to update a commit that was
> created somewhere else to UTC).  That way, we do not have to futz
> with TZ environment or tzset.

Yes, I think this is simpler and nicer than the proposal in my other reply.

In addition to not having to futz with TZ, I think I like the semantics better. The motivation that started this thread was not so much "I want to set a custom timezone to blend in" but rather "why are we recording the timezone at all here?" In that context, it makes sense to me to have a setting such as

	core.recordTimeZone

that I can turn *off* to say that I don't think datestamp() callers should consider the timezone to be information worth recording (and instead they should write +0000). To me that seems a little simpler to understand than user.hideTimezone since this focuses on turning some functionality off (recording of the time zone) instead of turning on a new stealth mode.

Thanks, Jonathan