Re: [PATCH] Re: Make 'git show' more useful

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Jul 14, 2009, 00:00 UTC
Message-ID: <alpine.LFD.2.01.0907131652120.13838@localhost.localdomain>
In-Reply-To: <1247528614-24590-1-git-send-email-bonzini@gnu.org>

On Tue, 14 Jul 2009, Paolo Bonzini wrote:

> 
> So, what about squashing this with Linus's patch?  (This is meant to be
> squashed, which is why this text is not in a cover letter).

I wouldn't squash it.

That said, in the original commit that introduced "no_walk" (ba1d4505), I said

    I was going to add "--no-walk" as a real argument flag to git-rev-list
    too, but I'm not sure anybody actually needs it. Although it might be
    useful for porcelain, so I left the door open.

and I never actually did it. That was Apr 15, 2006.

The actual "--no-walk" flag was then added over a year later by Dsco, in commit 8e64006eee ("Teach revision machinery about --no-walk").

Doing a "git log -p -S--no-walk", I have to admit that I don't find a single actual _use_ of --no-walk. And it obviously wasn't even exported until a year after it was internally implemented.

So I have to agree with the fact that "--no-walk" and "--do-walk" seem to be pretty worthless as command line switches. Removing them might be a good thing.

However, doing some googling, I do actually find examples of it on the web. And some of them even appear valid:

	second_parent=$(git rev-list --no-walk --parents $newrev | sed 's/ /\n/g' | grep -v $newrev | tail --lines=1)

because you can't use "git rev-parse" with --parents (of course, I'm not at all clear on why it doesn't do

	second_parent=$(git rev-parse "$newrev"^2)

but that's really immaterial - the point is that "git rev-parse" is _not_ a replacement for "git rev-list --no-walk").

So I dunno. I think we might as well leave --no-walk and --do-walk around, even though they are of dubious value. They do mirror the internal revision walking logic very directly.

			Linus