Merge branch 'ms/packet-err-check' into jt/fetch-v2-sideband

* ms/packet-err-check:
  pack-protocol.txt: accept error packets in any context
  Use packet_reader instead of packet_read_line

15 files changed, 174 insertions, 133 deletions

diff --git a/Documentation/technical/pack-protocol.txt b/Documentation/technical/pack-protocol.txt
index 6ac774d5f6..7a2375a55d 100644
--- a/Documentation/technical/pack-protocol.txt
+++ b/Documentation/technical/pack-protocol.txt
@@ -22,6 +22,16 @@ protocol-common.txt. When the grammar indicate `PKT-LINE(...)`, unless
 otherwise noted the usual pkt-line LF rules apply: the sender SHOULD
 include a LF, but the receiver MUST NOT complain if it is not present.
 
+An error packet is a special pkt-line that contains an error string.
+
+----
+  error-line     =  PKT-LINE("ERR" SP explanation-text)
+----
+
+Throughout the protocol, where `PKT-LINE(...)` is expected, an error packet MAY
+be sent. Once this packet is sent by a client or a server, the data transfer
+process defined in this protocol is terminated.
+
 Transports
 ----------
 There are three transports over which the packfile protocol is
@@ -89,13 +99,6 @@ process on the server side over the Git protocol is this:
      "0039git-upload-pack /schacon/gitbook.git\0host=example.com\0" |
      nc -v example.com 9418
 
-If the server refuses the request for some reasons, it could abort
-gracefully with an error message.
-
-----
-  error-line     =  PKT-LINE("ERR" SP explanation-text)
-----
-
 
 SSH Transport
 -------------
@@ -398,12 +401,11 @@ from the client).
 Then the server will start sending its packfile data.
 
 ----
-  server-response = *ack_multi ack / nak / error-line
+  server-response = *ack_multi ack / nak
   ack_multi       = PKT-LINE("ACK" SP obj-id ack_status)
   ack_status      = "continue" / "common" / "ready"
   ack             = PKT-LINE("ACK" SP obj-id)
   nak             = PKT-LINE("NAK")
-  error-line     =  PKT-LINE("ERR" SP explanation-text)
 ----
 
 A simple clone may look like this (with no 'have' lines):
diff --git a/builtin/archive.c b/builtin/archive.c
index d2455237ce..45d11669aa 100644
--- a/builtin/archive.c
+++ b/builtin/archive.c
@@ -27,10 +27,10 @@ static int run_remote_archiver(int argc, const char **argv,
 			       const char *remote, const char *exec,
 			       const char *name_hint)
 {
-	char *buf;
 	int fd[2], i, rv;
 	struct transport *transport;
 	struct remote *_remote;
+	struct packet_reader reader;
 
 	_remote = remote_get(remote);
 	if (!_remote->url[0])
@@ -53,18 +53,19 @@ static int run_remote_archiver(int argc, const char **argv,
 		packet_write_fmt(fd[1], "argument %s\n", argv[i]);
 	packet_flush(fd[1]);
 
-	buf = packet_read_line(fd[0], NULL);
-	if (!buf)
+	packet_reader_init(&reader, fd[0], NULL, 0,
+			   PACKET_READ_CHOMP_NEWLINE |
+			   PACKET_READ_DIE_ON_ERR_PACKET);
+
+	if (packet_reader_read(&reader) != PACKET_READ_NORMAL)
 		die(_("git archive: expected ACK/NAK, got a flush packet"));
-	if (strcmp(buf, "ACK")) {
-		if (starts_with(buf, "NACK "))
-			die(_("git archive: NACK %s"), buf + 5);
-		if (starts_with(buf, "ERR "))
-			die(_("remote error: %s"), buf + 4);
+	if (strcmp(reader.line, "ACK")) {
+		if (starts_with(reader.line, "NACK "))
+			die(_("git archive: NACK %s"), reader.line + 5);
 		die(_("git archive: protocol error"));
 	}
 
-	if (packet_read_line(fd[0], NULL))
+	if (packet_reader_read(&reader) != PACKET_READ_FLUSH)
 		die(_("git archive: expected a flush"));
 
 	/* Now, start reading from fd[0] and spit it out to stdout */
diff --git a/builtin/fetch-pack.c b/builtin/fetch-pack.c
index 63e69a5801..85dbc2af87 100644
--- a/builtin/fetch-pack.c
+++ b/builtin/fetch-pack.c
@@ -217,7 +217,8 @@ int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
 
 	packet_reader_init(&reader, fd[0], NULL, 0,
 			   PACKET_READ_CHOMP_NEWLINE |
-			   PACKET_READ_GENTLE_ON_EOF);
+			   PACKET_READ_GENTLE_ON_EOF |
+			   PACKET_READ_DIE_ON_ERR_PACKET);
 
 	switch (discover_version(&reader)) {
 	case protocol_v2:
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 33187bd8e9..d58b7750b6 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1569,30 +1569,29 @@ static void queue_commands_from_cert(struct command **tail,
 	}
 }
 
-static struct command *read_head_info(struct oid_array *shallow)
+static struct command *read_head_info(struct packet_reader *reader,
+				      struct oid_array *shallow)
 {
 	struct command *commands = NULL;
 	struct command **p = &commands;
 	for (;;) {
-		char *line;
-		int len, linelen;
+		int linelen;
 
-		line = packet_read_line(0, &len);
-		if (!line)
+		if (packet_reader_read(reader) != PACKET_READ_NORMAL)
 			break;
 
-		if (len > 8 && starts_with(line, "shallow ")) {
+		if (reader->pktlen > 8 && starts_with(reader->line, "shallow ")) {
 			struct object_id oid;
-			if (get_oid_hex(line + 8, &oid))
+			if (get_oid_hex(reader->line + 8, &oid))
 				die("protocol error: expected shallow sha, got '%s'",
-				    line + 8);
+				    reader->line + 8);
 			oid_array_append(shallow, &oid);
 			continue;
 		}
 
-		linelen = strlen(line);
-		if (linelen < len) {
-			const char *feature_list = line + linelen + 1;
+		linelen = strlen(reader->line);
+		if (linelen < reader->pktlen) {
+			const char *feature_list = reader->line + linelen + 1;
 			if (parse_feature_request(feature_list, "report-status"))
 				report_status = 1;
 			if (parse_feature_request(feature_list, "side-band-64k"))
@@ -1607,28 +1606,32 @@ static struct command *read_head_info(struct oid_array *shallow)
 				use_push_options = 1;
 		}
 
-		if (!strcmp(line, "push-cert")) {
+		if (!strcmp(reader->line, "push-cert")) {
 			int true_flush = 0;
-			char certbuf[1024];
+			int saved_options = reader->options;
+			reader->options &= ~PACKET_READ_CHOMP_NEWLINE;
 
 			for (;;) {
-				len = packet_read(0, NULL, NULL,
-						  certbuf, sizeof(certbuf), 0);
-				if (!len) {
+				packet_reader_read(reader);
+				if (reader->status == PACKET_READ_FLUSH) {
 					true_flush = 1;
 					break;
 				}
-				if (!strcmp(certbuf, "push-cert-end\n"))
+				if (reader->status != PACKET_READ_NORMAL) {
+					die("protocol error: got an unexpected packet");
+				}
+				if (!strcmp(reader->line, "push-cert-end\n"))
 					break; /* end of cert */
-				strbuf_addstr(&push_cert, certbuf);
+				strbuf_addstr(&push_cert, reader->line);
 			}
+			reader->options = saved_options;
 
 			if (true_flush)
 				break;
 			continue;
 		}
 
-		p = queue_command(p, line, linelen);
+		p = queue_command(p, reader->line, linelen);
 	}
 
 	if (push_cert.len)
@@ -1637,18 +1640,14 @@ static struct command *read_head_info(struct oid_array *shallow)
 	return commands;
 }
 
-static void read_push_options(struct string_list *options)
+static void read_push_options(struct packet_reader *reader,
+			      struct string_list *options)
 {
 	while (1) {
-		char *line;
-		int len;
-
-		line = packet_read_line(0, &len);
-
-		if (!line)
+		if (packet_reader_read(reader) != PACKET_READ_NORMAL)
 			break;
 
-		string_list_append(options, line);
+		string_list_append(options, reader->line);
 	}
 }
 
@@ -1924,6 +1923,7 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 	struct oid_array shallow = OID_ARRAY_INIT;
 	struct oid_array ref = OID_ARRAY_INIT;
 	struct shallow_info si;
+	struct packet_reader reader;
 
 	struct option options[] = {
 		OPT__QUIET(&quiet, N_("quiet")),
@@ -1986,12 +1986,16 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 	if (advertise_refs)
 		return 0;
 
-	if ((commands = read_head_info(&shallow)) != NULL) {
+	packet_reader_init(&reader, 0, NULL, 0,
+			   PACKET_READ_CHOMP_NEWLINE |
+			   PACKET_READ_DIE_ON_ERR_PACKET);
+
+	if ((commands = read_head_info(&reader, &shallow)) != NULL) {
 		const char *unpack_status = NULL;
 		struct string_list push_options = STRING_LIST_INIT_DUP;
 
 		if (use_push_options)
-			read_push_options(&push_options);
+			read_push_options(&reader, &push_options);
 		if (!check_cert_push_options(&push_options)) {
 			struct command *cmd;
 			for (cmd = commands; cmd; cmd = cmd->next)
diff --git a/builtin/send-pack.c b/builtin/send-pack.c
index 8e3c7490f7..098ebf22d0 100644
--- a/builtin/send-pack.c
+++ b/builtin/send-pack.c
@@ -250,7 +250,8 @@ int cmd_send_pack(int argc, const char **argv, const char *prefix)
 
 	packet_reader_init(&reader, fd[0], NULL, 0,
 			   PACKET_READ_CHOMP_NEWLINE |
-			   PACKET_READ_GENTLE_ON_EOF);
+			   PACKET_READ_GENTLE_ON_EOF |
+			   PACKET_READ_DIE_ON_ERR_PACKET);
 
 	switch (discover_version(&reader)) {
 	case protocol_v2:
diff --git a/connect.c b/connect.c
index 24281b6082..4813f005ab 100644
--- a/connect.c
+++ b/connect.c
@@ -296,7 +296,6 @@ struct ref **get_remote_heads(struct packet_reader *reader,
 	struct ref **orig_list = list;
 	int len = 0;
 	enum get_remote_heads_state state = EXPECTING_FIRST_REF;
-	const char *arg;
 
 	*list = NULL;
 
@@ -306,8 +305,6 @@ struct ref **get_remote_heads(struct packet_reader *reader,
 			die_initial_contact(1);
 		case PACKET_READ_NORMAL:
 			len = reader->pktlen;
-			if (len > 4 && skip_prefix(reader->line, "ERR ", &arg))
-				die(_("remote error: %s"), arg);
 			break;
 		case PACKET_READ_FLUSH:
 			state = EXPECTING_DONE;
diff --git a/fetch-pack.c b/fetch-pack.c
index dd6700bda9..ee0847e6ae 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -135,38 +135,42 @@ enum ack_type {
 	ACK_ready
 };
 
-static void consume_shallow_list(struct fetch_pack_args *args, int fd)
+static void consume_shallow_list(struct fetch_pack_args *args,
+				 struct packet_reader *reader)
 {
 	if (args->stateless_rpc && args->deepen) {
 		/* If we sent a depth we will get back "duplicate"
 		 * shallow and unshallow commands every time there
 		 * is a block of have lines exchanged.
 		 */
-		char *line;
-		while ((line = packet_read_line(fd, NULL))) {
-			if (starts_with(line, "shallow "))
+		while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
+			if (starts_with(reader->line, "shallow "))
 				continue;
-			if (starts_with(line, "unshallow "))
+			if (starts_with(reader->line, "unshallow "))
 				continue;
 			die(_("git fetch-pack: expected shallow list"));
 		}
+		if (reader->status != PACKET_READ_FLUSH)
+			die(_("git fetch-pack: expected a flush packet after shallow list"));
 	}
 }
 
-static enum ack_type get_ack(int fd, struct object_id *result_oid)
+static enum ack_type get_ack(struct packet_reader *reader,
+			     struct object_id *result_oid)
 {
 	int len;
-	char *line = packet_read_line(fd, &len);
 	const char *arg;
 
-	if (!line)
+	if (packet_reader_read(reader) != PACKET_READ_NORMAL)
 		die(_("git fetch-pack: expected ACK/NAK, got a flush packet"));
-	if (!strcmp(line, "NAK"))
+	len = reader->pktlen;
+
+	if (!strcmp(reader->line, "NAK"))
 		return NAK;
-	if (skip_prefix(line, "ACK ", &arg)) {
+	if (skip_prefix(reader->line, "ACK ", &arg)) {
 		if (!get_oid_hex(arg, result_oid)) {
 			arg += 40;
-			len -= arg - line;
+			len -= arg - reader->line;
 			if (len < 1)
 				return ACK;
 			if (strstr(arg, "continue"))
@@ -178,9 +182,7 @@ static enum ack_type get_ack(int fd, struct object_id *result_oid)
 			return ACK;
 		}
 	}
-	if (skip_prefix(line, "ERR ", &arg))
-		die(_("remote error: %s"), arg);
-	die(_("git fetch-pack: expected ACK/NAK, got '%s'"), line);
+	die(_("git fetch-pack: expected ACK/NAK, got '%s'"), reader->line);
 }
 
 static void send_request(struct fetch_pack_args *args,
@@ -248,10 +250,15 @@ static int find_common(struct fetch_negotiator *negotiator,
 	int got_ready = 0;
 	struct strbuf req_buf = STRBUF_INIT;
 	size_t state_len = 0;
+	struct packet_reader reader;
 
 	if (args->stateless_rpc && multi_ack == 1)
 		die(_("--stateless-rpc requires multi_ack_detailed"));
 
+	packet_reader_init(&reader, fd[0], NULL, 0,
+			   PACKET_READ_CHOMP_NEWLINE |
+			   PACKET_READ_DIE_ON_ERR_PACKET);
+
 	if (!args->no_dependents) {
 		mark_tips(negotiator, args->negotiation_tips);
 		for_each_cached_alternate(negotiator, insert_one_alternate_object);
@@ -336,31 +343,30 @@ static int find_common(struct fetch_negotiator *negotiator,
 	state_len = req_buf.len;
 
 	if (args->deepen) {
-		char *line;
 		const char *arg;
 		struct object_id oid;
 
 		send_request(args, fd[1], &req_buf);
-		while ((line = packet_read_line(fd[0], NULL))) {
-			if (skip_prefix(line, "shallow ", &arg)) {
+		while (packet_reader_read(&reader) == PACKET_READ_NORMAL) {
+			if (skip_prefix(reader.line, "shallow ", &arg)) {
 				if (get_oid_hex(arg, &oid))
-					die(_("invalid shallow line: %s"), line);
+					die(_("invalid shallow line: %s"), reader.line);
 				register_shallow(the_repository, &oid);
 				continue;
 			}
-			if (skip_prefix(line, "unshallow ", &arg)) {
+			if (skip_prefix(reader.line, "unshallow ", &arg)) {
 				if (get_oid_hex(arg, &oid))
-					die(_("invalid unshallow line: %s"), line);
+					die(_("invalid unshallow line: %s"), reader.line);
 				if (!lookup_object(the_repository, oid.hash))
-					die(_("object not found: %s"), line);
+					die(_("object not found: %s"), reader.line);
 				/* make sure that it is parsed as shallow */
 				if (!parse_object(the_repository, &oid))
-					die(_("error in object: %s"), line);
+					die(_("error in object: %s"), reader.line);
 				if (unregister_shallow(&oid))
-					die(_("no shallow found: %s"), line);
+					die(_("no shallow found: %s"), reader.line);
 				continue;
 			}
-			die(_("expected shallow/unshallow, got %s"), line);
+			die(_("expected shallow/unshallow, got %s"), reader.line);
 		}
 	} else if (!args->stateless_rpc)
 		send_request(args, fd[1], &req_buf);
@@ -397,9 +403,9 @@ static int find_common(struct fetch_negotiator *negotiator,
 			if (!args->stateless_rpc && count == INITIAL_FLUSH)
 				continue;
 
-			consume_shallow_list(args, fd[0]);
+			consume_shallow_list(args, &reader);
 			do {
-				ack = get_ack(fd[0], result_oid);
+				ack = get_ack(&reader, result_oid);
 				if (ack)
 					print_verbose(args, _("got %s %d %s"), "ack",
 						      ack, oid_to_hex(result_oid));
@@ -469,9 +475,9 @@ done:
 	strbuf_release(&req_buf);
 
 	if (!got_ready || !no_done)
-		consume_shallow_list(args, fd[0]);
+		consume_shallow_list(args, &reader);
 	while (flushes || multi_ack) {
-		int ack = get_ack(fd[0], result_oid);
+		int ack = get_ack(&reader, result_oid);
 		if (ack) {
 			print_verbose(args, _("got %s (%d) %s"), "ack",
 				      ack, oid_to_hex(result_oid));
@@ -1316,7 +1322,8 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
 	struct fetch_negotiator negotiator;
 	fetch_negotiator_init(&negotiator, negotiation_algorithm);
 	packet_reader_init(&reader, fd[0], NULL, 0,
-			   PACKET_READ_CHOMP_NEWLINE);
+			   PACKET_READ_CHOMP_NEWLINE |
+			   PACKET_READ_DIE_ON_ERR_PACKET);
 
 	while (state != FETCH_DONE) {
 		switch (state) {
diff --git a/pkt-line.c b/pkt-line.c
index 04d10bbd03..e70ea6d88f 100644
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -346,6 +346,10 @@ enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
 		return PACKET_READ_EOF;
 	}
 
+	if ((options & PACKET_READ_DIE_ON_ERR_PACKET) &&
+	    starts_with(buffer, "ERR "))
+		die(_("remote error: %s"), buffer + 4);
+
 	if ((options & PACKET_READ_CHOMP_NEWLINE) &&
 	    len && buffer[len-1] == '\n')
 		len--;
diff --git a/pkt-line.h b/pkt-line.h
index 5b28d43472..d7e1dbc047 100644
--- a/pkt-line.h
+++ b/pkt-line.h
@@ -62,9 +62,13 @@ int write_packetized_from_buf(const char *src_in, size_t len, int fd_out);
  *
  * If options contains PACKET_READ_CHOMP_NEWLINE, a trailing newline (if
  * present) is removed from the buffer before returning.
+ *
+ * If options contains PACKET_READ_DIE_ON_ERR_PACKET, it dies when it sees an
+ * ERR packet.
  */
-#define PACKET_READ_GENTLE_ON_EOF (1u<<0)
-#define PACKET_READ_CHOMP_NEWLINE (1u<<1)
+#define PACKET_READ_GENTLE_ON_EOF     (1u<<0)
+#define PACKET_READ_CHOMP_NEWLINE     (1u<<1)
+#define PACKET_READ_DIE_ON_ERR_PACKET (1u<<2)
 int packet_read(int fd, char **src_buffer, size_t *src_len, char
 		*buffer, unsigned size, int options);
 
diff --git a/remote-curl.c b/remote-curl.c
index 1220dffcdc..10b50869c5 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -204,7 +204,8 @@ static struct ref *parse_git_refs(struct discovery *heads, int for_push)
 
 	packet_reader_init(&reader, -1, heads->buf, heads->len,
 			   PACKET_READ_CHOMP_NEWLINE |
-			   PACKET_READ_GENTLE_ON_EOF);
+			   PACKET_READ_GENTLE_ON_EOF |
+			   PACKET_READ_DIE_ON_ERR_PACKET);
 
 	heads->version = discover_version(&reader);
 	switch (heads->version) {
@@ -409,28 +410,37 @@ static struct discovery *discover_refs(const char *service, int for_push)
 	if (maybe_smart &&
 	    (5 <= last->len && last->buf[4] == '#') &&
 	    !strbuf_cmp(&exp, &type)) {
-		char *line;
+		struct packet_reader reader;
+		packet_reader_init(&reader, -1, last->buf, last->len,
+				   PACKET_READ_CHOMP_NEWLINE |
+				   PACKET_READ_DIE_ON_ERR_PACKET);
 
 		/*
 		 * smart HTTP response; validate that the service
 		 * pkt-line matches our request.
 		 */
-		line = packet_read_line_buf(&last->buf, &last->len, NULL);
-		if (!line)
+		if (packet_reader_read(&reader) != PACKET_READ_NORMAL)
 			die("invalid server response; expected service, got flush packet");
 
 		strbuf_reset(&exp);
 		strbuf_addf(&exp, "# service=%s", service);
-		if (strcmp(line, exp.buf))
-			die("invalid server response; got '%s'", line);
+		if (strcmp(reader.line, exp.buf))
+			die("invalid server response; got '%s'", reader.line);
 		strbuf_release(&exp);
 
 		/* The header can include additional metadata lines, up
 		 * until a packet flush marker.  Ignore these now, but
 		 * in the future we might start to scan them.
 		 */
-		while (packet_read_line_buf(&last->buf, &last->len, NULL))
-			;
+		for (;;) {
+			packet_reader_read(&reader);
+			if (reader.pktlen <= 0) {
+				break;
+			}
+		}
+
+		last->buf = reader.src_buffer;
+		last->len = reader.src_len;
 
 		last->proto_git = 1;
 	} else if (maybe_smart &&
@@ -1174,7 +1184,8 @@ static void proxy_state_init(struct proxy_state *p, const char *service_name,
 		p->headers = curl_slist_append(p->headers, buf.buf);
 
 	packet_reader_init(&p->reader, p->in, NULL, 0,
-			   PACKET_READ_GENTLE_ON_EOF);
+			   PACKET_READ_GENTLE_ON_EOF |
+			   PACKET_READ_DIE_ON_ERR_PACKET);
 
 	strbuf_release(&buf);
 }
diff --git a/send-pack.c b/send-pack.c
index f692686770..7b9829f165 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -135,38 +135,36 @@ static int pack_objects(int fd, struct ref *refs, struct oid_array *extra, struc
 	return 0;
 }
 
-static int receive_unpack_status(int in)
+static int receive_unpack_status(struct packet_reader *reader)
 {
-	const char *line = packet_read_line(in, NULL);
-	if (!line)
+	if (packet_reader_read(reader) != PACKET_READ_NORMAL)
 		return error(_("unexpected flush packet while reading remote unpack status"));
-	if (!skip_prefix(line, "unpack ", &line))
-		return error(_("unable to parse remote unpack status: %s"), line);
-	if (strcmp(line, "ok"))
-		return error(_("remote unpack failed: %s"), line);
+	if (!skip_prefix(reader->line, "unpack ", &reader->line))
+		return error(_("unable to parse remote unpack status: %s"), reader->line);
+	if (strcmp(reader->line, "ok"))
+		return error(_("remote unpack failed: %s"), reader->line);
 	return 0;
 }
 
-static int receive_status(int in, struct ref *refs)
+static int receive_status(struct packet_reader *reader, struct ref *refs)
 {
 	struct ref *hint;
 	int ret;
 
 	hint = NULL;
-	ret = receive_unpack_status(in);
+	ret = receive_unpack_status(reader);
 	while (1) {
-		char *refname;
+		const char *refname;
 		char *msg;
-		char *line = packet_read_line(in, NULL);
-		if (!line)
+		if (packet_reader_read(reader) != PACKET_READ_NORMAL)
 			break;
-		if (!starts_with(line, "ok ") && !starts_with(line, "ng ")) {
-			error("invalid ref status from remote: %s", line);
+		if (!starts_with(reader->line, "ok ") && !starts_with(reader->line, "ng ")) {
+			error("invalid ref status from remote: %s", reader->line);
 			ret = -1;
 			break;
 		}
 
-		refname = line + 3;
+		refname = reader->line + 3;
 		msg = strchr(refname, ' ');
 		if (msg)
 			*msg++ = '\0';
@@ -187,7 +185,7 @@ static int receive_status(int in, struct ref *refs)
 			continue;
 		}
 
-		if (line[0] == 'o' && line[1] == 'k')
+		if (reader->line[0] == 'o' && reader->line[1] == 'k')
 			hint->status = REF_STATUS_OK;
 		else {
 			hint->status = REF_STATUS_REMOTE_REJECT;
@@ -390,6 +388,7 @@ int send_pack(struct send_pack_args *args,
 	int ret;
 	struct async demux;
 	const char *push_cert_nonce = NULL;
+	struct packet_reader reader;
 
 	/* Does the other end support the reporting? */
 	if (server_supports("report-status"))
@@ -559,6 +558,10 @@ int send_pack(struct send_pack_args *args,
 		in = demux.out;
 	}
 
+	packet_reader_init(&reader, in, NULL, 0,
+			   PACKET_READ_CHOMP_NEWLINE |
+			   PACKET_READ_DIE_ON_ERR_PACKET);
+
 	if (need_pack_data && cmds_sent) {
 		if (pack_objects(out, remote_refs, extra_have, args) < 0) {
 			for (ref = remote_refs; ref; ref = ref->next)
@@ -573,7 +576,7 @@ int send_pack(struct send_pack_args *args,
 			 * are failing, and just want the error() side effects.
 			 */
 			if (status_report)
-				receive_unpack_status(in);
+				receive_unpack_status(&reader);
 
 			if (use_sideband) {
 				close(demux.out);
@@ -590,7 +593,7 @@ int send_pack(struct send_pack_args *args,
 		packet_flush(out);
 
 	if (status_report && cmds_sent)
-		ret = receive_status(in, remote_refs);
+		ret = receive_status(&reader, remote_refs);
 	else
 		ret = 0;
 	if (args->stateless_rpc)
diff --git a/serve.c b/serve.c
index bda085f09c..317256c1a4 100644
--- a/serve.c
+++ b/serve.c
@@ -167,7 +167,8 @@ static int process_request(void)
 
 	packet_reader_init(&reader, 0, NULL, 0,
 			   PACKET_READ_CHOMP_NEWLINE |
-			   PACKET_READ_GENTLE_ON_EOF);
+			   PACKET_READ_GENTLE_ON_EOF |
+			   PACKET_READ_DIE_ON_ERR_PACKET);
 
 	/*
 	 * Check to see if the client closed their end before sending another
@@ -175,7 +176,7 @@ static int process_request(void)
 	 */
 	if (packet_reader_peek(&reader) == PACKET_READ_EOF)
 		return 1;
-	reader.options = PACKET_READ_CHOMP_NEWLINE;
+	reader.options &= ~PACKET_READ_GENTLE_ON_EOF;
 
 	while (state != PROCESS_REQUEST_DONE) {
 		switch (packet_reader_peek(&reader)) {
diff --git a/t/t5703-upload-pack-ref-in-want.sh b/t/t5703-upload-pack-ref-in-want.sh
index 7053899cb5..f87b2f6df3 100755
--- a/t/t5703-upload-pack-ref-in-want.sh
+++ b/t/t5703-upload-pack-ref-in-want.sh
@@ -208,7 +208,7 @@ test_expect_success 'server is initially ahead - no ref in want' '
 	cp -r "$LOCAL_PRISTINE" local &&
 	inconsistency master 1234567890123456789012345678901234567890 &&
 	test_must_fail git -C local fetch 2>err &&
-	test_i18ngrep "ERR upload-pack: not our ref" err
+	test_i18ngrep "fatal: remote error: upload-pack: not our ref" err
 '
 
 test_expect_success 'server is initially ahead - ref in want' '
@@ -254,7 +254,7 @@ test_expect_success 'server loses a ref - ref in want' '
 	echo "s/master/raster/" >"$HTTPD_ROOT_PATH/one-time-sed" &&
 	test_must_fail git -C local fetch 2>err &&
 
-	test_i18ngrep "ERR unknown ref refs/heads/raster" err
+	test_i18ngrep "fatal: remote error: unknown ref refs/heads/raster" err
 '
 
 stop_httpd
diff --git a/transport.c b/transport.c
index 99678153c1..e078812897 100644
--- a/transport.c
+++ b/transport.c
@@ -273,7 +273,8 @@ static struct ref *handshake(struct transport *transport, int for_push,
 
 	packet_reader_init(&reader, data->fd[0], NULL, 0,
 			   PACKET_READ_CHOMP_NEWLINE |
-			   PACKET_READ_GENTLE_ON_EOF);
+			   PACKET_READ_GENTLE_ON_EOF |
+			   PACKET_READ_DIE_ON_ERR_PACKET);
 
 	data->version = discover_version(&reader);
 	switch (data->version) {
diff --git a/upload-pack.c b/upload-pack.c
index 5e81f1ff24..08b547cf01 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -354,7 +354,8 @@ static int ok_to_give_up(const struct object_array *have_obj,
 					    min_generation);
 }
 
-static int get_common_commits(struct object_array *have_obj,
+static int get_common_commits(struct packet_reader *reader,
+			      struct object_array *have_obj,
 			      struct object_array *want_obj)
 {
 	struct object_id oid;
@@ -366,12 +367,11 @@ static int get_common_commits(struct object_array *have_obj,
 	save_commit_buffer = 0;
 
 	for (;;) {
-		char *line = packet_read_line(0, NULL);
 		const char *arg;
 
 		reset_timeout();
 
-		if (!line) {
+		if (packet_reader_read(reader) != PACKET_READ_NORMAL) {
 			if (multi_ack == 2 && got_common
 			    && !got_other && ok_to_give_up(have_obj, want_obj)) {
 				sent_ready = 1;
@@ -390,7 +390,7 @@ static int get_common_commits(struct object_array *have_obj,
 			got_other = 0;
 			continue;
 		}
-		if (skip_prefix(line, "have ", &arg)) {
+		if (skip_prefix(reader->line, "have ", &arg)) {
 			switch (got_oid(arg, &oid, have_obj)) {
 			case -1: /* they have what we do not */
 				got_other = 1;
@@ -416,7 +416,7 @@ static int get_common_commits(struct object_array *have_obj,
 			}
 			continue;
 		}
-		if (!strcmp(line, "done")) {
+		if (!strcmp(reader->line, "done")) {
 			if (have_obj->nr > 0) {
 				if (multi_ack)
 					packet_write_fmt(1, "ACK %s\n", last_hex);
@@ -425,7 +425,7 @@ static int get_common_commits(struct object_array *have_obj,
 			packet_write_fmt(1, "NAK\n");
 			return -1;
 		}
-		die("git upload-pack: expected SHA1 list, got '%s'", line);
+		die("git upload-pack: expected SHA1 list, got '%s'", reader->line);
 	}
 }
 
@@ -826,7 +826,7 @@ static int process_deepen_not(const char *line, struct string_list *deepen_not,
 	return 0;
 }
 
-static void receive_needs(struct object_array *want_obj)
+static void receive_needs(struct packet_reader *reader, struct object_array *want_obj)
 {
 	struct object_array shallows = OBJECT_ARRAY_INIT;
 	struct string_list deepen_not = STRING_LIST_INIT_DUP;
@@ -840,33 +840,32 @@ static void receive_needs(struct object_array *want_obj)
 		struct object *o;
 		const char *features;
 		struct object_id oid_buf;
-		char *line = packet_read_line(0, NULL);
 		const char *arg;
 
 		reset_timeout();
-		if (!line)
+		if (packet_reader_read(reader) != PACKET_READ_NORMAL)
 			break;
 
-		if (process_shallow(line, &shallows))
+		if (process_shallow(reader->line, &shallows))
 			continue;
-		if (process_deepen(line, &depth))
+		if (process_deepen(reader->line, &depth))
 			continue;
-		if (process_deepen_since(line, &deepen_since, &deepen_rev_list))
+		if (process_deepen_since(reader->line, &deepen_since, &deepen_rev_list))
 			continue;
-		if (process_deepen_not(line, &deepen_not, &deepen_rev_list))
+		if (process_deepen_not(reader->line, &deepen_not, &deepen_rev_list))
 			continue;
 
-		if (skip_prefix(line, "filter ", &arg)) {
+		if (skip_prefix(reader->line, "filter ", &arg)) {
 			if (!filter_capability_requested)
 				die("git upload-pack: filtering capability not negotiated");
 			parse_list_objects_filter(&filter_options, arg);
 			continue;
 		}
 
-		if (!skip_prefix(line, "want ", &arg) ||
+		if (!skip_prefix(reader->line, "want ", &arg) ||
 		    parse_oid_hex(arg, &oid_buf, &features))
 			die("git upload-pack: protocol error, "
-			    "expected to get object ID, not '%s'", line);
+			    "expected to get object ID, not '%s'", reader->line);
 
 		if (parse_feature_request(features, "deepen-relative"))
 			deepen_relative = 1;
@@ -1055,6 +1054,7 @@ void upload_pack(struct upload_pack_options *options)
 {
 	struct string_list symref = STRING_LIST_INIT_DUP;
 	struct object_array want_obj = OBJECT_ARRAY_INIT;
+	struct packet_reader reader;
 
 	stateless_rpc = options->stateless_rpc;
 	timeout = options->timeout;
@@ -1078,10 +1078,14 @@ void upload_pack(struct upload_pack_options *options)
 	if (options->advertise_refs)
 		return;
 
-	receive_needs(&want_obj);
+	packet_reader_init(&reader, 0, NULL, 0,
+			   PACKET_READ_CHOMP_NEWLINE |
+			   PACKET_READ_DIE_ON_ERR_PACKET);
+
+	receive_needs(&reader, &want_obj);
 	if (want_obj.nr) {
 		struct object_array have_obj = OBJECT_ARRAY_INIT;
-		get_common_commits(&have_obj, &want_obj);
+		get_common_commits(&reader, &have_obj, &want_obj);
 		create_pack_file(&have_obj, &want_obj);
 	}
 }