Re: [PATCH 2/4] revision traversal: retire BOUNDARY_SHOW

Johannes Schindelin [off-list ref] writes:

On Mon, 5 Mar 2007, Junio C Hamano wrote:

quoted

This removes the flag internally used by revision traversal to
decide which commits are indeed boundaries and renames it to
CHILD_SHOWN.  builtin-bundle uses the symbol for its
verification, but I think the logic it uses it is wrong.  The
flag is still useful but it is local to the git-bundle, so it is
renamed to PREREQ_MARK.

The idea was to bail out of revision walking when that prerequisite was 
found, _even_ if it happened to be uninteresting.

Just marking the parents uninteresting unless they are prerequisites would 
be better, probably.

quoted

 
 	i = req_nr;
 	while (i && (commit = get_revision(&revs)))
-		if (commit->object.flags & BOUNDARY_SHOW)
+		if (commit->object.flags & PREREQ_MARK)
 			i--;

The above-mentioned idea, then would be: instead of just i--; do

I explicitly wanted to avoid that.  If the generated bundle had
prereqs that are not independent of each other, doing that would
hide some prereqs.

This should help performance, as not all reachable commits are traversed 
any more.

You prevented that with "while (i &&" part already, didn't you?

Wasn't --skip meant for something like gitweb, where you just want to skip 
the first <n> commits from the list, but do not want to change the list 
otherwise?

Yes, but does the patch change that?

quoted

@@ -1305,6 +1309,9 @@ struct commit *get_revision(struct rev_info *revs)
 	case -1:
 		break;
 	case 0:
+		/* Although we grabbed it, it is not shown. */
+		if (c)
+			c->object.flags &= ~SHOWN;
 		c = NULL;

Is this really relevant in practice?

Absolutely.  But I have further updates on this series.