revision: Fix --topo-order and --max-age with reachability limiting.

What ends up not working very well at all is the combination of
"--topo-order" and the output filter in get_revision. It will
return NULL when we see the first commit out of date-order, even
if we have other commits coming.

So we really should do the "past the date order" thing in
get_revision() only if we have _not_ done it already in
limit_list().

Something like this.

The easiest way to test this is with just

	gitk --since=3.days.ago

on the kernel tree. Without this patch, it tends to be pretty obviously
broken.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

revision.c

@@ -783,19 +783,21 @@ struct commit *get_revision(struct rev_info *revs)
 
 		/*
 		 * If we haven't done the list limiting, we need to look at
-		 * the parents here
+		 * the parents here. We also need to do the date-based limiting
+		 * that we'd otherwise have done in limit_list().
 		 */
-		if (!revs->limited)
+		if (!revs->limited) {
+			if (revs->max_age != -1 && (commit->date < revs->max_age))
+				continue;
 			add_parents_to_list(revs, commit, &revs->commits);
+		}
 		if (commit->object.flags & SHOWN)
 			continue;
 		if (!(commit->object.flags & BOUNDARY) &&
 		    (commit->object.flags & UNINTERESTING))
 			continue;
 		if (revs->min_age != -1 && (commit->date > revs->min_age))
 			continue;
-		if (revs->max_age != -1 && (commit->date < revs->max_age))
-			return NULL;
 		if (revs->no_merges &&
 		    commit->parents && commit->parents->next)
 			continue;