Re: How do get a specific version of a particular file?

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Feb 28, 2007, 00:22 UTC
Message-ID: <Pine.LNX.4.64.0702271605290.12485@woody.linux-foundation.org>
In-Reply-To: <7vfy8rb2do.fsf@assigned-by-dhcp.cox.net>

On Tue, 27 Feb 2007, Junio C Hamano wrote:

Show 19 quoted lines

> merlyn@stonehenge.com (Randal L. Schwartz) writes:
> 
> >>>>>> "Theodore" == Theodore Tso <tytso@mit.edu> writes:
> >
> > Theodore> And I'm still not sure why
> >
> > Theodore> 	git show v1.5.0..v1.5.0.1 
> >
> > Theodore> doesn't throw an error, and why it prints what it does...
> >
> > Wait, that doesn't throw an error?
> >
> > (tries it)
> >
> > OK, how is that different from git-diff ?
> 
> I do not think there is any difference.  "show" is about
> multiple points, not ranges.  "diff" is about multiple
> (typically two) points, and not ranges.

Well, I do think Ted has a good point. Having negative refs makes no sense for the "no-walk" case (aka "git show").

So when we do

	git show v1.4.4..v1.5.0

that's an illogical thing to do, since "git show" is defined to be a non-revision-walking action, which means the range operator be pointless and wrong. The fact that we happily accept it (and then _only_ show v1.5.0, which is the positive end of the range) is quite arguably not very logical.

We should complain, and say that you can only do "no_walk" with positive refs. Negative object refs really don't make any sense unless you walk the obejct list (or you're "git diff" and know about ranges explicitly).

Something like this (although I don't know if my message is necessarily the best possible one).

		Linus

---

diff --git a/revision.c b/revision.c
index 4cf697e..b84c066 100644
--- a/revision.c
+++ b/revision.c
@@ -116,6 +116,8 @@ void mark_parents_uninteresting(struct commit *commit)
 
 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
 {
+	if (revs->no_walk && (obj->flags & UNINTERESTING))
+		die("object ranges do not make sense when not walking revisions");
 	add_object_array(obj, name, &revs->pending);
 	if (revs->reflog_info && obj->type == OBJ_COMMIT)
 		add_reflog_for_walk(revs->reflog_info,