Re: git and time

From: Junio C Hamano <junkio@cox.net>
Date: Sep 29, 2006, 22:27 UTC
Message-ID: <7vd59ejokp.fsf@assigned-by-dhcp.cox.net>
In-Reply-To: <Pine.LNX.4.64.0609281029300.9349@xanadu.home>

Nicolas Pitre <nico@cam.org> writes:

Show 24 quoted lines

> On Wed, 27 Sep 2006, Junio C Hamano wrote:
>
>> Nicolas Pitre <nico@cam.org> writes:
>> 
>> > SYNOPSIS
>> >
>> > 	git-local-arrival <committish>
>> >
>> > DESCRIPTION
>> >
>> > 	The command displays the time when given commit appeared in the 
>> > 	local repository.
>> 
>> This should be certainly doable, but local-arrival may not be
>> interesting if the repository has more than one branches.  Maybe
>> 
>> 	git-local-arrival <committish> [<branch>]
>> 
>> which defaults to the current branch?
>
> Indeed.  I didn't mention it initially because it is really easy to do 
> once you have it working for the current branch.  The technical 
> challenge is about making it efficient to find out which reflog entry 
> with a path to given commit is the oldest.

The more I think about this, if we were to add yet another command, I think it should be a command that lets us inspect ref-log. We do not have an UI other than @{time} syntax to interact with it right now.

What are the things we would want?  Here is a strawman.

 - List when and how a branch was changed.

   git ref-log --list --type=merge next (when did I merge into my 'next'?)
   git ref-log --list --type=merge (ditto but any branches)
   git ref-log --list next (any changes not just 'merge')

   I expect the output would give timestamp and reason comment;
   in addition the branch name when no branch is specified.
   Type does not have to be a concrete thing -- it could just be
   a substring match in the reason comment string.

   Also we would limit output with -n <limit>.  The output
   should be sorted by the timestamp of ref-log entry -- we are
   talking about a particular repository's ref-log, so its
   timestamp has more sane meaning than in distributed case.
   
 - Find which branches currently contains a commit, and find the
   earliest time that the commit became part of each of them.

   git ref-log $commit next master (when did it enter 'next' and
                                    when did it graduate to 'master'?)
   git ref-log $commit (ditto but any branches)

   I expect the output to be the timestamp and reason comment;
   in addition the branch name when no branch is specified.

Also for a shared repository, the person who made the change would be a reasonable thing to report.

So for consistency, in all cases we could make the output format like this:

    branch SP time-and-zone SP name SP email SP reason-comment LF

where time-and-zone is human-readable timestamp as we see in git-log output.