[PATCH 7/7] push: clarify rejection of update to non-commit-ish

[Chris Rorvick <chris@rorvick.com>]

Pushes must already (by default) update to a commit-ish due the fast-
forward check in set_ref_status_for_push().  But rejecting for not being
a fast-forward suggests the situation can be resolved with a merge.
Flag these updates (i.e., to a blob or a tree) as not forwardable so the
user is presented with more appropriate advice.

Signed-off-by: Chris Rorvick <chris@rorvick.com>
---
 remote.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/remote.c b/remote.c
index f5bc4e7..ee0c1e5 100644
--- a/remote.c
+++ b/remote.c
@@ -1291,6 +1291,11 @@ static inline int is_forwardable(struct ref* ref)
 	if (!o || o->type != OBJ_COMMIT)
 		return 0;
 
+	/* new object must be commit-ish */
+	o = deref_tag(parse_object(ref->new_sha1), NULL, 0);
+	if (!o || o->type != OBJ_COMMIT)
+		return 0;
+
 	return 1;
 }
 
-- 
1.8.0.209.gf3828dc