merge(3p/git): Merge git subtree at v2.29.2 r/1890

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

1 files changed, 15 insertions, 3 deletions

diff --git a/third_party/git/pkt-line.c b/third_party/git/pkt-line.c
index a0e87b1e8140..844c253ccd9a 100644
--- a/third_party/git/pkt-line.c
+++ b/third_party/git/pkt-line.c
@@ -99,6 +99,13 @@ void packet_delim(int fd)
 		die_errno(_("unable to write delim packet"));
 }
 
+void packet_response_end(int fd)
+{
+	packet_trace("0002", 4, 1);
+	if (write_in_full(fd, "0002", 4) < 0)
+		die_errno(_("unable to write stateless separator packet"));
+}
+
 int packet_flush_gently(int fd)
 {
 	packet_trace("0000", 4, 1);
@@ -306,10 +313,10 @@ static int get_packet_data(int fd, char **src_buf, size_t *src_size,
 	return ret;
 }
 
-static int packet_length(const char *linelen)
+int packet_length(const char lenbuf_hex[4])
 {
-	int val = hex2chr(linelen);
-	return (val < 0) ? val : (val << 8) | hex2chr(linelen + 2);
+	int val = hex2chr(lenbuf_hex);
+	return (val < 0) ? val : (val << 8) | hex2chr(lenbuf_hex + 2);
 }
 
 enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
@@ -337,6 +344,10 @@ enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
 		packet_trace("0001", 4, 0);
 		*pktlen = 0;
 		return PACKET_READ_DELIM;
+	} else if (len == 2) {
+		packet_trace("0002", 4, 0);
+		*pktlen = 0;
+		return PACKET_READ_RESPONSE_END;
 	} else if (len < 4) {
 		die(_("protocol error: bad line length %d"), len);
 	}
@@ -479,6 +490,7 @@ void packet_reader_init(struct packet_reader *reader, int fd,
 	reader->buffer_size = sizeof(packet_buffer);
 	reader->options = options;
 	reader->me = "git";
+	reader->hash_algo = &hash_algos[GIT_HASH_SHA1];
 }
 
 enum packet_read_status packet_reader_read(struct packet_reader *reader)