1 files changed, 35 insertions, 21 deletions

diff --git a/remote.c b/remote.c
index ca1f8f2eaf..9e21b1d787 100644
--- a/remote.c
+++ b/remote.c
@@ -1285,6 +1285,8 @@ void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
 	struct ref *ref;
 
 	for (ref = remote_refs; ref; ref = ref->next) {
+		int force_ref_update = ref->force || force_update;
+
 		if (ref->peer_ref)
 			hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
 		else if (!send_mirror)
@@ -1297,34 +1299,46 @@ void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
 			continue;
 		}
 
-		/* This part determines what can overwrite what.
-		 * The rules are:
-		 *
-		 * (0) you can always use --force or +A:B notation to
-		 *     selectively force individual ref pairs.
+		/*
+		 * Decide whether an individual refspec A:B can be
+		 * pushed.  The push will succeed if any of the
+		 * following are true:
 		 *
-		 * (1) if the old thing does not exist, it is OK.
+		 * (1) the remote reference B does not exist
 		 *
-		 * (2) if you do not have the old thing, you are not allowed
-		 *     to overwrite it; you would not know what you are losing
-		 *     otherwise.
+		 * (2) the remote reference B is being removed (i.e.,
+		 *     pushing :B where no source is specified)
 		 *
-		 * (3) if both new and old are commit-ish, and new is a
-		 *     descendant of old, it is OK.
+		 * (3) the destination is not under refs/tags/, and
+		 *     if the old and new value is a commit, the new
+		 *     is a descendant of the old.
 		 *
-		 * (4) regardless of all of the above, removing :B is
-		 *     always allowed.
+		 * (4) it is forced using the +A:B notation, or by
+		 *     passing the --force argument
 		 */
 
-		ref->nonfastforward =
+		ref->update =
 			!ref->deletion &&
-			!is_null_sha1(ref->old_sha1) &&
-			(!has_sha1_file(ref->old_sha1)
-			  || !ref_newer(ref->new_sha1, ref->old_sha1));
-
-		if (ref->nonfastforward && !ref->force && !force_update) {
-			ref->status = REF_STATUS_REJECT_NONFASTFORWARD;
-			continue;
+			!is_null_sha1(ref->old_sha1);
+
+		if (ref->update) {
+			ref->nonfastforward =
+				!has_sha1_file(ref->old_sha1)
+				  || !ref_newer(ref->new_sha1, ref->old_sha1);
+
+			if (!prefixcmp(ref->name, "refs/tags/")) {
+				ref->requires_force = 1;
+				if (!force_ref_update) {
+					ref->status = REF_STATUS_REJECT_ALREADY_EXISTS;
+					continue;
+				}
+			} else if (ref->nonfastforward) {
+				ref->requires_force = 1;
+				if (!force_ref_update) {
+					ref->status = REF_STATUS_REJECT_NONFASTFORWARD;
+					continue;
+				}
+			}
 		}
 	}
 }