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[PATCH 2/4] do not send client agent unless server does first

From
Jeff King <peff@peff.net>
Date
Aug 10, 2012, 07:57 UTC
Message-ID
<20120810075743.GB8399@sigill.intra.peff.net>
In-Reply-To
<20120810075342.GA30072@sigill.intra.peff.net>

Commit ff5effdf taught both clients and servers of the git protocol to send an "agent" capability that just advertises their version for statistics and debugging purposes. However, the protocol-capabilities.txt document indicates that the client's advertisement is actually a response, and should never include capabilities not mentioned in the server's advertisement.

Adding the unconditional advertisement in the server programs was OK, then, but the clients broke the protocol. The server implementation of git-core itself does not care, but at least one does: the Google Code git server will hang up with an internal error upon seeing an unknown capability.

Instead, each client must record whether we saw an agent string from the server, and respond with its agent only if the server mentioned it first.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/fetch-pack.c |  7 ++++++-
 builtin/send-pack.c  | 12 +++++++++---
 2 files changed, 15 insertions(+), 4 deletions(-)
diff --git a/builtin/fetch-pack.c b/builtin/fetch-pack.c
index fe56596..bc7a0f9 100644
--- a/builtin/fetch-pack.c
+++ b/builtin/fetch-pack.c
@@ -19,6 +19,7 @@ static int prefer_ofs_delta = 1;
 static int no_done;
 static int fetch_fsck_objects = -1;
 static int transfer_fsck_objects = -1;
+static int agent_supported;
 static struct fetch_pack_args args = {
 	/* .uploadpack = */ "git-upload-pack",
 };
@@ -328,7 +329,8 @@ static int find_common(int fd[2], unsigned char *result_sha1,
 			if (args.no_progress)   strbuf_addstr(&c, " no-progress");
 			if (args.include_tag)   strbuf_addstr(&c, " include-tag");
 			if (prefer_ofs_delta)   strbuf_addstr(&c, " ofs-delta");
-			strbuf_addf(&c, " agent=%s", git_user_agent_sanitized());
+			if (agent_supported)    strbuf_addf(&c, " agent=%s",
+							    git_user_agent_sanitized());
 			packet_buf_write(&req_buf, "want %s%s\n", remote_hex, c.buf);
 			strbuf_release(&c);
 		} else
@@ -821,6 +823,9 @@ static struct ref *do_fetch_pack(int fd[2],
 			fprintf(stderr, "Server supports ofs-delta\n");
 	} else
 		prefer_ofs_delta = 0;
+	if (server_supports("agent"))
+		agent_supported = 1;
+
 	if (everything_local(&ref, nr_match, match)) {
 		packet_flush(fd[1]);
 		goto all_done;
diff --git a/builtin/send-pack.c b/builtin/send-pack.c
index 5c69995..7d05064 100644
--- a/builtin/send-pack.c
+++ b/builtin/send-pack.c
@@ -252,6 +252,7 @@ int send_pack(struct send_pack_args *args,
 	int status_report = 0;
 	int use_sideband = 0;
 	int quiet_supported = 0;
+	int agent_supported = 0;
 	unsigned cmds_sent = 0;
 	int ret;
 	struct async demux;
@@ -267,6 +268,8 @@ int send_pack(struct send_pack_args *args,
 		use_sideband = 1;
 	if (server_supports("quiet"))
 		quiet_supported = 1;
+	if (server_supports("agent"))
+		agent_supported = 1;
 
 	if (!remote_refs) {
 		fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
@@ -306,14 +309,17 @@ int send_pack(struct send_pack_args *args,
 			char *new_hex = sha1_to_hex(ref->new_sha1);
 			int quiet = quiet_supported && (args->quiet || !args->progress);
 
-			if (!cmds_sent && (status_report || use_sideband || quiet)) {
+			if (!cmds_sent && (status_report || use_sideband ||
+					   quiet || agent_supported)) {
 				packet_buf_write(&req_buf,
-						 "%s %s %s%c%s%s%s agent=%s",
+						 "%s %s %s%c%s%s%s%s%s",
 						 old_hex, new_hex, ref->name, 0,
 						 status_report ? " report-status" : "",
 						 use_sideband ? " side-band-64k" : "",
 						 quiet ? " quiet" : "",
-						 git_user_agent_sanitized());
+						 agent_supported ? " agent=" : "",
+						 agent_supported ? git_user_agent_sanitized() : ""
+						);
 			}
 			else
 				packet_buf_write(&req_buf, "%s %s %s",
-- 
1.7.12.rc2.4.g7f05cf9
Previous: Jeff KingNext: Junio C Hamano
Message 3 of 37 in “jk/version-string and google code”
  1. 0/4 jk/version-string and google codeJeff King, Aug 10, 2012
  2. 1/4 send-pack: fix capability-sending logicJeff King, Aug 10, 2012
  3. 2/4 do not send client agent unless server does firstJeff King, Aug 10, 2012
  4. Junio C HamanoAug 10, 2012
  5. Jeff KingAug 10, 2012
  6. 3/4 connect: learn to parse capabilities with valuesJeff King, Aug 10, 2012
  7. Eric SunshineAug 10, 2012
  8. Junio C HamanoAug 10, 2012
  9. Jeff KingAug 10, 2012
  10. Junio C HamanoAug 10, 2012
  11. Junio C HamanoAug 13, 2012
  12. 4/4 fetch-pack: mention server version with verbose outputJunio C Hamano, Aug 13, 2012
  13. Junio C HamanoAug 13, 2012
  14. Jeff KingAug 13, 2012
  15. Junio C HamanoAug 13, 2012
  16. Jeff KingAug 13, 2012
  17. Junio C HamanoAug 13, 2012
  18. Jeff KingAug 13, 2012
  19. Jeff KingAug 14, 2012
  20. Jeff KingAug 14, 2012
  21. Junio C HamanoAug 14, 2012
  22. 4/4 fetch-pack: mention server version with verbose outputJeff King, Aug 10, 2012
  23. Junio C HamanoAug 10, 2012
  24. Jeff KingAug 10, 2012
  25. Junio C HamanoAug 10, 2012
  26. Jeff KingAug 10, 2012
  27. Shawn PearceAug 10, 2012
  28. Junio C HamanoAug 10, 2012
  29. Junio C HamanoAug 10, 2012
  30. Dave BorowitzAug 10, 2012
  31. Jeff KingAug 10, 2012
  32. Dave BorowitzAug 10, 2012
  33. Jeff KingAug 10, 2012
  34. Junio C HamanoAug 10, 2012
  35. Jeff KingAug 10, 2012
  36. Junio C HamanoAug 10, 2012
  37. Junio C HamanoAug 10, 2012

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