Merge branch 'bw/protocol-v1'

A new mechanism to upgrade the wire protocol in place is proposed
and demonstrated that it works with the older versions of Git
without harming them.

* bw/protocol-v1:
  Documentation: document Extra Parameters
  ssh: introduce a 'simple' ssh variant
  i5700: add interop test for protocol transition
  http: tell server that the client understands v1
  connect: tell server that the client understands v1
  connect: teach client to recognize v1 server response
  upload-pack, receive-pack: introduce protocol version 1
  daemon: recognize hidden request arguments
  protocol: introduce protocol extension mechanisms
  pkt-line: add packet_write function
  connect: in ref advertisement, shallows are last

1 files changed, 10 insertions, 0 deletions

diff --git a/cache.h b/cache.h
index 2e14345051..cb5db7bf83 100644
--- a/cache.h
+++ b/cache.h
@@ -451,6 +451,16 @@ static inline enum object_type object_type(unsigned int mode)
 #define GIT_OPTIONAL_LOCKS_ENVIRONMENT "GIT_OPTIONAL_LOCKS"
 
 /*
+ * Environment variable used in handshaking the wire protocol.
+ * Contains a colon ':' separated list of keys with optional values
+ * 'key[=value]'.  Presence of unknown keys and values must be
+ * ignored.
+ */
+#define GIT_PROTOCOL_ENVIRONMENT "GIT_PROTOCOL"
+/* HTTP header used to handshake the wire protocol */
+#define GIT_PROTOCOL_HEADER "Git-Protocol"
+
+/*
  * This environment variable is expected to contain a boolean indicating
  * whether we should or should not treat:
  *