Subject: Re: breakage in revision traversal with pathspec

From: Junio C Hamano <[email-masked]>
Date: Fri, 20 Sep 2013 10:51:55 -0700

Jeff King <[email-masked]> writes:

> My original question was going to be: why bother peeling at all if we
> are just going to push the outer objects, anyway?
>
> And after staring at it, I somehow convinced myself that the answer was
> that you were pushing both. But that is not the case. Sorry for the
> noise.

But that is still a valid point, and the patch to avoid peeling for
non symmetric diff does not look too bad, either.

 revision.c               | 59 ++++++++++++++++++++++++++++++------------------
 t/t6000-rev-list-misc.sh |  8 +++++++
 2 files changed, 45 insertions(+), 22 deletions(-)

diff --git a/revision.c b/revision.c
index 68545c8..7010aff 100644
--- a/revision.c
+++ b/revision.c
@@ -1157,41 +1157,56 @@ int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsi
 		}
 		if (!get_sha1_committish(this, from_sha1) &&
 		    !get_sha1_committish(next, sha1)) {
-			struct commit *a, *b;
-			struct commit_list *exclude;
-
-			a = lookup_commit_reference(from_sha1);
-			b = lookup_commit_reference(sha1);
-			if (!a || !b) {
-				if (revs->ignore_missing)
-					return 0;
-				die(symmetric ?
-				    "Invalid symmetric difference expression %s...%s" :
-				    "Invalid revision range %s..%s",
-				    arg, next);
-			}
+			struct object *a_obj, *b_obj;
 
 			if (!cant_be_filename) {
 				*dotdot = '.';
 				verify_non_filename(revs->prefix, arg);
 			}
 
-			if (symmetric) {
+			a_obj = parse_object(from_sha1);
+			b_obj = parse_object(sha1);
+			if (!a_obj || !b_obj) {
+			missing:
+				if (revs->ignore_missing)
+					return 0;
+				die(symmetric
+				    ? "Invalid symmetric difference expression %s"
+				    : "Invalid revision range %s", arg);
+			}
+
+			if (!symmetric) {
+				/* just A..B */
+				a_flags = flags_exclude;
+			} else {
+				/* A...B -- find merge bases between the two */
+				struct commit *a, *b;
+				struct commit_list *exclude;
+
+				a = (a_obj->type == OBJ_COMMIT
+				     ? (struct commit *)a_obj
+				     : lookup_commit_reference(a_obj->sha1));
+				b = (b_obj->type == OBJ_COMMIT
+				     ? (struct commit *)b_obj
+				     : lookup_commit_reference(b_obj->sha1));
+				if (!a || !b)
+					goto missing;
 				exclude = get_merge_bases(a, b, 1);
 				add_pending_commit_list(revs, exclude,
 							flags_exclude);
 				free_commit_list(exclude);
+
 				a_flags = flags | SYMMETRIC_LEFT;
-			} else
-				a_flags = flags_exclude;
-			a->object.flags |= a_flags;
-			b->object.flags |= flags;
-			add_rev_cmdline(revs, &a->object, this,
+			}
+
+			a_obj->flags |= a_flags;
+			b_obj->flags |= flags;
+			add_rev_cmdline(revs, a_obj, this,
 					REV_CMD_LEFT, a_flags);
-			add_rev_cmdline(revs, &b->object, next,
+			add_rev_cmdline(revs, b_obj, next,
 					REV_CMD_RIGHT, flags);
-			add_pending_object(revs, &a->object, this);
-			add_pending_object(revs, &b->object, next);
+			add_pending_object(revs, a_obj, this);
+			add_pending_object(revs, b_obj, next);
 			return 0;
 		}
 		*dotdot = '.';
diff --git a/t/t6000-rev-list-misc.sh b/t/t6000-rev-list-misc.sh
index b10685a..15e3d64 100755
--- a/t/t6000-rev-list-misc.sh
+++ b/t/t6000-rev-list-misc.sh
@@ -48,4 +48,12 @@ test_expect_success 'rev-list --objects with pathspecs and copied files' '
 	! grep one output
 '
 
+test_expect_success 'rev-list A..B and rev-list ^A B are the same' '
+	git commit --allow-empty -m another &&
+	git tag -a -m "annotated" v1.0 &&
+	git rev-list --objects ^v1.0^ v1.0 >expect &&
+	git rev-list --objects v1.0^..v1.0 >actual &&
+	test_cmp expect actual
+'
+
 test_done