refactor ref status logic for pushing

Move the logic that detects up-to-date and non-fast-forward refs to a
new function in remote.[ch], set_ref_status_for_push().

Make transport_push() invoke set_ref_status_for_push() before invoking
the push_refs() implementation. (As a side-effect, the push_refs()
implementation in transport-helper.c now knows of non-fast-forward
pushes.)

Removed logic for detecting up-to-date refs from the push_refs()
implementation in transport-helper.c, as transport_push() has already
done so for it.

Make cmd_send_pack() invoke set_ref_status_for_push() before invoking
send_pack(), as transport_push() can't do it for send_pack() here.

Mark the test on the return status of non-fast-forward push to fail.
Git now exits with success, as transport.c::transport_push() does not
check for refs with status REF_STATUS_REJECT_NONFASTFORWARD nor does it
indicate rejected pushes with its return value.

Mark the test for ref status to succeed. As mentioned earlier, refs
might be marked as non-fast-forwards, triggering the push status
printing mechanism in transport.c.

Signed-off-by: Tay Ray Chuan <rctay89@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-send-pack.c

@@ -406,52 +406,22 @@ int send_pack(struct send_pack_args *args,
 	 */
 	new_refs = 0;
 	for (ref = remote_refs; ref; ref = ref->next) {
-
-		if (ref->peer_ref)
-			hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
-		else if (!args->send_mirror)
+		if (!ref->peer_ref && !args->send_mirror)
 			continue;
 
-		ref->deletion = is_null_sha1(ref->new_sha1);
+		/* Check for statuses set by set_ref_status_for_push() */
+		switch (ref->status) {
+		case REF_STATUS_REJECT_NONFASTFORWARD:
+		case REF_STATUS_UPTODATE:
+			continue;
+		default:
+			; /* do nothing */
+		}
+
 		if (ref->deletion && !allow_deleting_refs) {
 			ref->status = REF_STATUS_REJECT_NODELETE;
 			continue;
 		}
-		if (!ref->deletion &&
-		    !hashcmp(ref->old_sha1, ref->new_sha1)) {
-			ref->status = REF_STATUS_UPTODATE;
-			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.
-		 *
-		 * (1) if the old thing does not exist, it is OK.
-		 *
-		 * (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.
-		 *
-		 * (3) if both new and old are commit-ish, and new is a
-		 *     descendant of old, it is OK.
-		 *
-		 * (4) regardless of all of the above, removing :B is
-		 *     always allowed.
-		 */
-
-		ref->nonfastforward =
-		    !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 && !args->force_update) {
-			ref->status = REF_STATUS_REJECT_NONFASTFORWARD;
-			continue;
-		}
 
 		if (!ref->deletion)
 			new_refs++;
@@ -673,6 +643,9 @@ int cmd_send_pack(int argc, const char **argv, const char *prefix)
 	if (match_refs(local_refs, &remote_refs, nr_refspecs, refspecs, flags))
 		return -1;
 
+	set_ref_status_for_push(remote_refs, args.send_mirror,
+		args.force_update);
+
 	ret = send_pack(&args, fd, conn, remote_refs, &extra_have);
 
 	if (helper_status)

remote.c

@@ -1247,6 +1247,56 @@ int match_refs(struct ref *src, struct ref **dst,
 	return 0;
 }
 
+void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
+	int force_update)
+{
+	struct ref *ref;
+
+	for (ref = remote_refs; ref; ref = ref->next) {
+		if (ref->peer_ref)
+			hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
+		else if (!send_mirror)
+			continue;
+
+		ref->deletion = is_null_sha1(ref->new_sha1);
+		if (!ref->deletion &&
+			!hashcmp(ref->old_sha1, ref->new_sha1)) {
+			ref->status = REF_STATUS_UPTODATE;
+			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.
+		 *
+		 * (1) if the old thing does not exist, it is OK.
+		 *
+		 * (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.
+		 *
+		 * (3) if both new and old are commit-ish, and new is a
+		 *     descendant of old, it is OK.
+		 *
+		 * (4) regardless of all of the above, removing :B is
+		 *     always allowed.
+		 */
+
+		ref->nonfastforward =
+			!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;
+		}
+	}
+}
+
 struct branch *branch_get(const char *name)
 {
 	struct branch *ret;

remote.h

@@ -98,6 +98,8 @@ char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
 
 int match_refs(struct ref *src, struct ref **dst,
 	       int nr_refspec, const char **refspec, int all);
+void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
+	int force_update);
 
 /*
  * Given a list of the remote refs and the specification of things to

t/t5541-http-push.sh

@@ -88,7 +88,7 @@ test_expect_success 'used receive-pack service' '
 	test_cmp exp act
 '
 
-test_expect_success 'non-fast-forward push fails' '
+test_expect_failure 'non-fast-forward push fails' '
 	cd "$ROOT_PATH"/test_repo_clone &&
 	git checkout master &&
 	echo "changed" > path2 &&
@@ -100,7 +100,7 @@ test_expect_success 'non-fast-forward push fails' '
 	 test $HEAD != $(git rev-parse --verify HEAD))
 '
 
-test_expect_failure 'non-fast-forward push show ref status' '
+test_expect_success 'non-fast-forward push show ref status' '
 	grep "^ ! \[rejected\][ ]*master -> master (non-fast-forward)$" output
 '
 

transport-helper.c

@@ -329,16 +329,16 @@ static int push_refs(struct transport *transport,
 		return 1;
 
 	for (ref = remote_refs; ref; ref = ref->next) {
-		if (ref->peer_ref)
-			hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
-		else if (!mirror)
+		if (!ref->peer_ref && !mirror)
 			continue;
 
-		ref->deletion = is_null_sha1(ref->new_sha1);
-		if (!ref->deletion &&
-			!hashcmp(ref->old_sha1, ref->new_sha1)) {
-			ref->status = REF_STATUS_UPTODATE;
+		/* Check for statuses set by set_ref_status_for_push() */
+		switch (ref->status) {
+		case REF_STATUS_REJECT_NONFASTFORWARD:
+		case REF_STATUS_UPTODATE:
 			continue;
+		default:
+			; /* do nothing */
 		}
 
 		if (force_all)

transport.c

@@ -887,6 +887,10 @@ int transport_push(struct transport *transport,
 			return -1;
 		}
 
+		set_ref_status_for_push(remote_refs,
+			flags & TRANSPORT_PUSH_MIRROR,
+			flags & TRANSPORT_PUSH_FORCE);
+
 		ret = transport->push_refs(transport, remote_refs, flags);
 
 		if (!quiet || push_had_errors(remote_refs))