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From: Junio C Hamano <gitster@pobox.com>
To: Johannes Sixt <j6t@kdbg.org>
Cc: Johannes Schindelin <johannes.schindelin@gmx.de>,
	Git Mailing List <git@vger.kernel.org>
Subject: Re: Bug: rebase -i creates committer time inversions on 'reword'
Date: Mon, 16 Apr 2018 06:35:37 +0900	[thread overview]
Message-ID: <xmqq7ep817bq.fsf@gitster-ct.c.googlers.com> (raw)
In-Reply-To: <5f5d5b88-b3ac-ed4f-ee24-6ce2cba2bd55@kdbg.org> (Johannes Sixt's message of "Fri, 13 Apr 2018 18:52:28 +0200")

Johannes Sixt <j6t@kdbg.org> writes:

> I just noticed that all commits in a 70-commit branch have the same
> committer timestamp. This is very unusual on Windows, where rebase -i of
> such a long branch takes more than one second (but not more than 3 or
> so thanks to the builtin nature of the command!).
>
> And, in fact, if you mark some commits with 'reword' to delay the quick
> processing of the patches, then the reworded commits have later time
> stamps, but subsequent not reworded commits receive the earlier time
> stamp. This is clearly not intended.

Hmm, I may be missing something without enough caffeine but I am
puzzled how that would be possible.  With a "few picks, an edit, and
a yet more picks" sequence, the first picks may share the same
timestamp due to the git_default_date caching (which I think is a
deliberate design choice we made), an edit that stops will let the
concluding "commit" (either by the end user or invoked internally
via "rebase --continue"), but because that process restarts afresh,
the commits made by "yet more picks" cannot share the timestamp that
was cached for the earliest ones from the same series, no?

Ah, do you mean we have an internal sequence like this, when "rebase
--continue" wants to conclude an edit/reword?

 - we figure out the committer ident, which grabs a timestamp and
   cache it;

 - we spawn "commit" to conclude the stopped step, letting it record
   its beginning time (which is a bit older than the above) or its
   ending time (which is much older due to human typing speed);

 - subsequent "picks" are made in the same process, and share the
   timestamp we grabbed in the first step, which is older than the
   second one.

I guess we'd want a mechanism to tell ident.c layer "discard the
cached one, as we are no longer in the same automated sequence", and
use that whenever we spawn an editor (or otherwise go interactive).

>
> Perhaps something like this below is needed.
>
> diff --git a/ident.c b/ident.c
> index 327abe557f..2c6bff7b9d 100644
> --- a/ident.c
> +++ b/ident.c
> @@ -178,8 +178,8 @@ const char *ident_default_email(void)
>  
>  static const char *ident_default_date(void)
>  {
> -	if (!git_default_date.len)
> -		datestamp(&git_default_date);
> +	strbuf_reset(&git_default_date);
> +	datestamp(&git_default_date);
>  	return git_default_date.buf;
>  }
>  

  parent reply	other threads:[~2018-04-15 21:37 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-13 16:52 Bug: rebase -i creates committer time inversions on 'reword' Johannes Sixt
2018-04-14 11:15 ` Phillip Wood
2018-04-14 13:11   ` Johannes Schindelin
2018-04-16  9:48     ` Phillip Wood
2018-04-19  9:17       ` Phillip Wood
2018-04-15 21:35 ` Junio C Hamano [this message]
2018-04-16  5:56   ` Johannes Sixt
2018-04-17  1:37     ` Junio C Hamano
2018-04-18 10:19     ` Phillip Wood
2018-04-18 10:22 ` [RFC PATCH] ident: don't cache default date Phillip Wood
2018-04-18 11:27   ` Ævar Arnfjörð Bjarmason
2018-04-18 17:47     ` Phillip Wood
2018-04-18 18:15       ` Johannes Sixt
2018-04-18 21:15         ` Junio C Hamano
2018-04-19  9:15         ` Phillip Wood
2018-04-20  8:11           ` Johannes Schindelin
2018-04-20  9:41             ` Phillip Wood

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