[PATCH v4 6/8] send-pack: new return code "ERROR_SEND_PACK_BAD_REF_STATUS"

[Patrick Steinhardt <ps@pks.im>]

From: Jiang Xin <zhiyou.jx@alibaba-inc.com>

The "push_refs" function in the transport_vtable is the handler for
git-push operation. All the "push_refs" functions for different
transports (protocols) should have the same behavior, but the behavior
of "git_transport_push()" function for builtin_smart_vtable in
"transport.c" (which calls "send_pack()" in "send-pack.c") differs from
the handler of the HTTP protocol.

The "push_refs()" function for the HTTP protocol which calls the
"push_refs_with_push()" function in "transport-helper.c" will return 0
even when a bad REF_STATUS (such as REF_STATUS_REJECT_NONFASTFORWARD)
was found. But "send_pack()" for Git smart protocol will return -1 for
a bad REF_STATUS.

We cannot ignore bad REF_STATUS directly in the "send_pack()" function,
because the function is also used in "builtin/send-pack.c". So we add a
new non-zero error code "SEND_PACK_ERROR_REF_STATUS" for "send_pack()".

Ignore the specific error code in the "git_transport_push()" function to
have the same behavior as "push_refs()" for HTTP protocol. Note that
even though we ignore the error here, we'll ultimately still end up
detecting that a subset of refs was not pushed in `transport_push()`
because we eventually call `push_had_errors()` on the remote refs.

Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 send-pack.c |  9 ++-------
 send-pack.h | 13 +++++++++++++
 transport.c |  7 +++++++
 3 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/send-pack.c b/send-pack.c
index 772c7683a0..4448c081cc 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -632,7 +632,7 @@ int send_pack(struct repository *r,
 				reject_atomic_push(remote_refs, args->send_mirror);
 				error("atomic push failed for ref %s. status: %d",
 				      ref->name, ref->status);
-				ret = args->porcelain ? 0 : -1;
+				ret = ERROR_SEND_PACK_BAD_REF_STATUS;
 				goto out;
 			}
 			/* else fallthrough */
@@ -763,11 +763,6 @@ int send_pack(struct repository *r,
 	if (ret < 0)
 		goto out;
 
-	if (args->porcelain) {
-		ret = 0;
-		goto out;
-	}
-
 	for (ref = remote_refs; ref; ref = ref->next) {
 		switch (ref->status) {
 		case REF_STATUS_NONE:
@@ -775,7 +770,7 @@ int send_pack(struct repository *r,
 		case REF_STATUS_OK:
 			break;
 		default:
-			ret = -1;
+			ret = ERROR_SEND_PACK_BAD_REF_STATUS;
 			goto out;
 		}
 	}
diff --git a/send-pack.h b/send-pack.h
index d256715681..c5ded2d200 100644
--- a/send-pack.h
+++ b/send-pack.h
@@ -13,6 +13,9 @@ struct repository;
 #define SEND_PACK_PUSH_CERT_IF_ASKED 1
 #define SEND_PACK_PUSH_CERT_ALWAYS 2
 
+/* At least one reference has been rejected by the remote side. */
+#define ERROR_SEND_PACK_BAD_REF_STATUS 1
+
 struct send_pack_args {
 	const char *url;
 	unsigned verbose:1,
@@ -36,6 +39,16 @@ struct option;
 int option_parse_push_signed(const struct option *opt,
 			     const char *arg, int unset);
 
+/*
+ * Compute a packfile and write it to a file descriptor. The `fd` array needs
+ * to contain two file descriptors: `fd[0]` is the file descriptor used as
+ * input for the packet reader, whereas `fd[1]` is the file descriptor the
+ * packfile will be written to.
+ *
+ * Returns 0 on success, non-zero otherwise. Negative return values indicate a
+ * generic error, whereas positive return values indicate specific error
+ * conditions as documented with the `ERROR_SEND_PACK_*` constants.
+ */
 int send_pack(struct repository *r, struct send_pack_args *args,
 	      int fd[], struct child_process *conn,
 	      struct ref *remote_refs, struct oid_array *extra_have);
diff --git a/transport.c b/transport.c
index 81ae8243b9..d064aff33e 100644
--- a/transport.c
+++ b/transport.c
@@ -934,6 +934,13 @@ static int git_transport_push(struct transport *transport, struct ref *remote_re
 	case protocol_v0:
 		ret = send_pack(the_repository, &args, data->fd, data->conn, remote_refs,
 				&data->extra_have);
+		/*
+		 * Ignore the specific error code to maintain consistent behavior
+		 * with the "push_refs()" function across different transports,
+		 * such as "push_refs_with_push()" for HTTP protocol.
+		 */
+		if (ret == ERROR_SEND_PACK_BAD_REF_STATUS)
+			ret = 0;
 		break;
 	case protocol_unknown_version:
 		BUG("unknown protocol version");

-- 
2.48.1.502.g6dc24dfdaf.dirty