push: flag updates that require force

Add a flag for indicating an update to a reference requires force.
Currently the `nonfastforward` flag is used for this when generating the
status message.  A separate flag insulates dependent logic from the
details of set_ref_status_for_push().

Signed-off-by: Chris Rorvick <chris@rorvick.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

cache.h

@@ -999,7 +999,9 @@ struct ref {
 	unsigned char old_sha1[20];
 	unsigned char new_sha1[20];
 	char *symref;
-	unsigned int force:1,
+	unsigned int
+		force:1,
+		requires_force:1,
 		merge:1,
 		nonfastforward:1,
 		not_forwardable:1,

remote.c

@@ -1293,6 +1293,8 @@ 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)
@@ -1335,9 +1337,12 @@ void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
 				!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;
+			if (ref->nonfastforward) {
+				ref->requires_force = 1;
+				if (!force_ref_update) {
+					ref->status = REF_STATUS_REJECT_NONFASTFORWARD;
+					continue;
+				}
 			}
 		}
 	}

transport.c

@@ -659,7 +659,7 @@ static void print_ok_ref_status(struct ref *ref, int porcelain)
 		const char *msg;
 
 		strcpy(quickref, status_abbrev(ref->old_sha1));
-		if (ref->nonfastforward) {
+		if (ref->requires_force) {
 			strcat(quickref, "...");
 			type = '+';
 			msg = "forced update";