Re: [PATCH gitk 0/4] gitk support for git log -L

From: Thomas Rast <trast@inf.ethz.ch>
Date: Aug 19, 2013, 08:21 UTC
Message-ID: <874namay5p.fsf@linux-k42r.v.cablecom.net>
In-Reply-To: <20130818115456.GA6772@iris.ozlabs.ibm.com>

Paul Mackerras <paulus@samba.org> writes:

Show 12 quoted lines

> Hi Thomas,
>
> On Wed, Jul 31, 2013 at 03:17:41PM +0200, Thomas Rast wrote:
>> Jens Lehmann <Jens.Lehmann@web.de> writes:
>> 
>> > Am 29.07.2013 21:37, schrieb Thomas Rast:
>> >> Thomas Rast <trast@inf.ethz.ch> writes:
>> >> 
>> >>> Thomas Rast <trast@inf.ethz.ch> writes:
>> >>>
>> >>>> Now that git log -L has hit master, I figure it's time to discuss the
>> >>>> corresponding change to gitk.

[...]

Show 5 quoted lines

>
> One thing I worry about is having gitk storing in memory not just the
> history graph but also all the diffs (assuming I have understood
> correctly what you're doing).  Gitk's memory consumption is already
> pretty large.  However, I can't see an alternative at this point.

I don't think there is one. log -L is pretty much an "all or nothing" thing at this point. I suppose if we really found that the diffs are regularly too big to be manageable for gitk, we could invent a porcelain mode where 'log -L' just prints the detected commits and corresponding line ranges, and then have a new option to diff-tree to let it again filter that range.

But note that ordinary 'git log -L' also buffers the entire set of diffs within less. The memory consumption of gitk to hold the same diffs in memory should be only a small factor of what less uses in the same scenario. Furthermore, users will typically ask for a small region of code (one function, or some such), so the diffs themselves are usually quite small, nowhere near the size of the full commit diffs.

Show 6 quoted lines

>> Unfortunately it's turning out to be harder than I hoped.  gitk runs the
>> arguments through git-rev-parse, which only knows that -n gets an
>> unstuck argument.  Consequently, gitk accepts an unstuck -n but only
>> stuck forms of -S and -G.
>
> Excuse my ignorance, but what do you mean by "stuck" vs. "unstuck"?

Whether the option value is a separate argument in argv, or directly stuck to the option.

stuck: gitk -L:foo:main.c unstuck: gitk -L :foo:main.c

Existing gitk chokes on 'gitk -S foo', but works with 'git -Sfoo'.

-- 
Thomas Rast
trast@{inf,student}.ethz.ch