[PATCH v3 00/11] Advertise session ID in protocol capabilities

[Josh Steadmon <steadmon@google.com>]

In order to more easily debug remote operations, it is useful to be able
to identify sessions on either side of the connection. This series
allows clients and servers to provide a unique session ID via a new
"session-id" protocol capability. This session ID can be logged on each
side of the connection, allowing logs to be joined during debugging
sessions.

Changes from V2:
* De-emphasize connection to trace2
* Renamed capability from "trace2-sid" to "session-id"
* Noted (lack of) session ID structure in capability docs
* Advertise SID regardless of whether trace2 is enabled
* Simplify conditionals
* Style cleanups

Changes since V1:
* Added a public trace2_session_id() function to trace2.{h,c}. Used this
  in place of tr2_sid_get().
* Fixed a style issue regarding using NULL rather than 0.

Josh Steadmon (11):
  docs: new capability to advertise session IDs
  docs: new transfer.advertiseSID option
  trace2: add a public function for getting the SID
  upload-pack: advertise session ID in v0 capabilities
  receive-pack: advertise session ID in v0 capabilities
  serve: advertise session ID in v2 capabilities
  transport: log received server session ID
  fetch-pack: advertise session ID in capabilities
  upload-pack, serve: log received client session ID
  send-pack: advertise session ID in capabilities
  receive-pack: log received client session ID

 Documentation/config/transfer.txt             |  4 +
 .../technical/protocol-capabilities.txt       | 17 +++-
 Documentation/technical/protocol-v2.txt       | 13 ++++
 builtin/receive-pack.c                        | 15 ++++
 fetch-pack.c                                  |  9 +++
 send-pack.c                                   |  7 ++
 serve.c                                       | 18 +++++
 t/t5705-session-id-in-capabilities.sh         | 78 +++++++++++++++++++
 trace2.c                                      |  5 ++
 trace2.h                                      |  2 +
 transport.c                                   | 10 +++
 upload-pack.c                                 | 23 +++++-
 12 files changed, 198 insertions(+), 3 deletions(-)
 create mode 100755 t/t5705-session-id-in-capabilities.sh

Range-diff against v2:
 1:  d04028c3c7 <  -:  ---------- docs: new capability to advertise trace2 SIDs
 2:  5d5097b671 <  -:  ---------- docs: new trace2.advertiseSID option
 -:  ---------- >  1:  184cabb6f5 docs: new capability to advertise session IDs
 -:  ---------- >  2:  937534065a docs: new transfer.advertiseSID option
 3:  7f42aacd2b =  3:  227c709ba5 trace2: add a public function for getting the SID
 4:  4912af5f2b !  4:  612957b9d5 upload-pack: advertise trace2 SID in v0 capabilities
    @@ Metadata
     Author: Josh Steadmon <steadmon@google.com>
     
      ## Commit message ##
    -    upload-pack: advertise trace2 SID in v0 capabilities
    +    upload-pack: advertise session ID in v0 capabilities
     
    -    When trace2 is enabled and trace2.advertiseSID is true, advertise
    -    upload-pack's trace2 session ID via the new trace2-sid capability.
    +    When transfer.advertiseSID is true, advertise upload-pack's session ID
    +    via the new session-id capability.
     
     
    @@ upload-pack.c: struct upload_pack_data {
      	unsigned done : 1;					/* v2 only */
      	unsigned allow_ref_in_want : 1;				/* v2 only */
      	unsigned allow_sideband_all : 1;			/* v2 only */
    -+	unsigned advertise_trace2_sid : 1;
    ++	unsigned advertise_sid : 1;
      };
      
      static void upload_pack_data_init(struct upload_pack_data *data)
    @@ upload-pack.c: static void upload_pack_data_init(struct upload_pack_data *data)
      	packet_writer_init(&data->writer, 1);
      
      	data->keepalive = 5;
    -+	data->advertise_trace2_sid = 0;
    ++	data->advertise_sid = 0;
      }
      
      static void upload_pack_data_clear(struct upload_pack_data *data)
    @@ upload-pack.c: static void format_symref_info(struct strbuf *buf, struct string_
      		strbuf_addf(buf, " symref=%s:%s", item->string, (char *)item->util);
      }
      
    -+static void format_trace2_info(struct strbuf *buf, struct upload_pack_data *d) {
    -+	if (d->advertise_trace2_sid && trace2_is_enabled())
    -+		strbuf_addf(buf, " trace2-sid=%s", trace2_session_id());
    ++static void format_session_id(struct strbuf *buf, struct upload_pack_data *d) {
    ++	if (d->advertise_sid)
    ++		strbuf_addf(buf, " session-id=%s", trace2_session_id());
     +}
     +
      static int send_ref(const char *refname, const struct object_id *oid,
    @@ upload-pack.c: static int send_ref(const char *refname, const struct object_id *
      
      	if (capabilities) {
      		struct strbuf symref_info = STRBUF_INIT;
    -+		struct strbuf trace2_info = STRBUF_INIT;
    ++		struct strbuf session_id = STRBUF_INIT;
      
      		format_symref_info(&symref_info, &data->symref);
     -		packet_write_fmt(1, "%s %s%c%s%s%s%s%s%s object-format=%s agent=%s\n",
    -+		format_trace2_info(&trace2_info, data);
    ++		format_session_id(&session_id, data);
     +		packet_write_fmt(1, "%s %s%c%s%s%s%s%s%s%s object-format=%s agent=%s\n",
      			     oid_to_hex(oid), refname_nons,
      			     0, capabilities,
    @@ upload-pack.c: static int send_ref(const char *refname, const struct object_id *
      			     data->stateless_rpc ? " no-done" : "",
      			     symref_info.buf,
      			     data->allow_filter ? " filter" : "",
    -+			     trace2_info.buf,
    ++			     session_id.buf,
      			     the_hash_algo->name,
      			     git_user_agent_sanitized());
      		strbuf_release(&symref_info);
    -+		strbuf_release(&trace2_info);
    ++		strbuf_release(&session_id);
      	} else {
      		packet_write_fmt(1, "%s %s\n", oid_to_hex(oid), refname_nons);
      	}
    @@ upload-pack.c: static int upload_pack_config(const char *var, const char *value,
      		data->allow_sideband_all = git_config_bool(var, value);
      	} else if (!strcmp("core.precomposeunicode", var)) {
      		precomposed_unicode = git_config_bool(var, value);
    -+	} else if (!strcmp("trace2.advertisesid", var)) {
    -+		data->advertise_trace2_sid = git_config_bool(var, value);
    ++	} else if (!strcmp("transfer.advertisesid", var)) {
    ++		data->advertise_sid = git_config_bool(var, value);
      	}
      
      	if (current_config_scope() != CONFIG_SCOPE_LOCAL &&
 5:  7003189c81 !  5:  32fe78f3e9 receive-pack: advertise trace2 SID in v0 capabilities
    @@ Metadata
     Author: Josh Steadmon <steadmon@google.com>
     
      ## Commit message ##
    -    receive-pack: advertise trace2 SID in v0 capabilities
    +    receive-pack: advertise session ID in v0 capabilities
     
    -    When trace2 is enabled and trace2.advertiseSID is true, advertise
    -    receive-pack's trace2 session ID via the new trace2-sid capability.
    +    When transfer.advertiseSID is true, advertise receive-pack's session ID
    +    via the new session-id capability.
     
     
    @@ builtin/receive-pack.c: static int receive_unpack_limit = -1;
      static int transfer_unpack_limit = -1;
      static int advertise_atomic_push = 1;
      static int advertise_push_options;
    -+static int advertise_trace2_sid;
    ++static int advertise_sid;
      static int unpack_limit = 100;
      static off_t max_input_size;
      static int report_status;
    @@ builtin/receive-pack.c: static int receive_pack_config(const char *var, const ch
      		return 0;
      	}
      
    -+	if (strcmp(var, "trace2.advertisesid") == 0) {
    -+		advertise_trace2_sid = git_config_bool(var, value);
    ++	if (strcmp(var, "transfer.advertisesid") == 0) {
    ++		advertise_sid = git_config_bool(var, value);
     +		return 0;
     +	}
     +
    @@ builtin/receive-pack.c: static void show_ref(const char *path, const struct obje
      			strbuf_addf(&cap, " push-cert=%s", push_cert_nonce);
      		if (advertise_push_options)
      			strbuf_addstr(&cap, " push-options");
    -+		if (advertise_trace2_sid && trace2_is_enabled())
    -+			strbuf_addf(&cap, " trace2-sid=%s", trace2_session_id());
    ++		if (advertise_sid)
    ++			strbuf_addf(&cap, " session-id=%s", trace2_session_id());
      		strbuf_addf(&cap, " object-format=%s", the_hash_algo->name);
      		strbuf_addf(&cap, " agent=%s", git_user_agent_sanitized());
      		packet_write_fmt(1, "%s %s%c%s\n",
 6:  9573428cc0 !  6:  fe6731cc09 serve: advertise trace2 SID in v2 capabilities
    @@ Metadata
     Author: Josh Steadmon <steadmon@google.com>
     
      ## Commit message ##
    -    serve: advertise trace2 SID in v2 capabilities
    +    serve: advertise session ID in v2 capabilities
     
    -    When trace2 is enabled and trace2.advertiseSID is true, advertise the
    -    server's trace2 session ID for all protocol v2 connections via the new
    -    trace2-sid capability.
    +    When transfer.advertiseSID is true, advertise the server's session ID
    +    for all protocol v2 connections via the new session-id capability.
     
     
    @@ serve.c
      #include "serve.h"
      #include "upload-pack.h"
      
    -+static int advertise_trace2_sid;
    ++static int advertise_sid;
     +
      static int always_advertise(struct repository *r,
      			    struct strbuf *value)
    @@ serve.c: static int object_format_advertise(struct repository *r,
      	return 1;
      }
      
    -+static int trace2_advertise(struct repository *r, struct strbuf *value)
    ++static int session_id_advertise(struct repository *r, struct strbuf *value)
     +{
    -+	if (!advertise_trace2_sid || !trace2_is_enabled())
    ++	if (!advertise_sid)
     +		return 0;
     +	if (value)
     +		strbuf_addstr(value, trace2_session_id());
    @@ serve.c: static struct protocol_capability capabilities[] = {
      	{ "fetch", upload_pack_advertise, upload_pack_v2 },
      	{ "server-option", always_advertise, NULL },
      	{ "object-format", object_format_advertise, NULL },
    -+	{ "trace2-sid", trace2_advertise, NULL },
    ++	{ "session-id", session_id_advertise, NULL },
      };
      
      static void advertise_capabilities(void)
    @@ serve.c: static int process_request(void)
      /* Main serve loop for protocol version 2 */
      void serve(struct serve_options *options)
      {
    -+	git_config_get_bool("trace2.advertisesid", &advertise_trace2_sid);
    ++	git_config_get_bool("transfer.advertisesid", &advertise_sid);
     +
      	if (options->advertise_capabilities || !options->stateless_rpc) {
      		/* serve by default supports v2 */
 7:  21bdbf23f3 !  7:  014cae8dc1 transport: log received server trace2 SID
    @@ Metadata
     Author: Josh Steadmon <steadmon@google.com>
     
      ## Commit message ##
    -    transport: log received server trace2 SID
    +    transport: log received server session ID
     
    -    When a client receives a trace2-sid capability from a protocol v0, v1,
    +    When a client receives a session-id capability from a protocol v0, v1,
         or v2 server, log the received session ID via a trace2 data event.
     
     
    - ## t/t5705-trace2-sid-in-capabilities.sh (new) ##
    + ## t/t5705-session-id-in-capabilities.sh (new) ##
     @@
     +#!/bin/sh
     +
    -+test_description='trace2 SID in capabilities'
    ++test_description='session ID in capabilities'
     +
     +. ./test-lib.sh
     +
     +REPO="$(pwd)/repo"
     +LOCAL_PRISTINE="$(pwd)/local_pristine"
     +
    -+test_expect_success 'setup repos for trace2 SID capability tests' '
    ++test_expect_success 'setup repos for session ID capability tests' '
     +	git init "$REPO" &&
     +	test_commit -C "$REPO" a &&
     +	git clone "file://$REPO" "$LOCAL_PRISTINE" &&
    @@ t/t5705-trace2-sid-in-capabilities.sh (new)
     +
     +for PROTO in 0 1 2
     +do
    -+	test_expect_success "trace2 session IDs not advertised by default (fetch v${PROTO})" '
    ++	test_expect_success "session IDs not advertised by default (fetch v${PROTO})" '
     +		test_when_finished "rm -rf local tr2-client-events" &&
     +		cp -r "$LOCAL_PRISTINE" local &&
     +		GIT_TRACE2_EVENT="$(pwd)/tr2-client-events" \
    @@ t/t5705-trace2-sid-in-capabilities.sh (new)
     +		test -z "$(grep \"key\":\"server-sid\" tr2-client-events)"
     +	'
     +
    -+	test_expect_success "trace2 session IDs not advertised by default (push v${PROTO})" '
    ++	test_expect_success "session IDs not advertised by default (push v${PROTO})" '
     +		test_when_finished "rm -rf local tr2-client-events" &&
     +		cp -r "$LOCAL_PRISTINE" local &&
     +		git -C local pull --no-rebase origin &&
    @@ t/t5705-trace2-sid-in-capabilities.sh (new)
     +done
     +
     +test_expect_success 'enable SID advertisement' '
    -+	git -C "$REPO" config trace2.advertiseSID true &&
    -+	git -C "$LOCAL_PRISTINE" config trace2.advertiseSID true
    ++	git -C "$REPO" config transfer.advertiseSID true &&
    ++	git -C "$LOCAL_PRISTINE" config transfer.advertiseSID true
     +'
     +
     +for PROTO in 0 1 2
     +do
    -+	test_expect_success "trace2 session IDs advertised (fetch v${PROTO})" '
    ++	test_expect_success "session IDs advertised (fetch v${PROTO})" '
     +		test_when_finished "rm -rf local tr2-client-events" &&
     +		cp -r "$LOCAL_PRISTINE" local &&
     +		GIT_TRACE2_EVENT="$(pwd)/tr2-client-events" \
    @@ t/t5705-trace2-sid-in-capabilities.sh (new)
     +		grep \"key\":\"server-sid\" tr2-client-events
     +	'
     +
    -+	test_expect_success "trace2 session IDs advertised (push v${PROTO})" '
    ++	test_expect_success "session IDs advertised (push v${PROTO})" '
     +		test_when_finished "rm -rf local tr2-client-events" &&
     +		cp -r "$LOCAL_PRISTINE" local &&
     +		git -C local pull --no-rebase origin &&
    @@ transport.c: static struct ref *handshake(struct transport *transport, int for_p
      	struct ref *refs = NULL;
      	struct packet_reader reader;
     +	int sid_len;
    -+	const char *server_trace2_sid;
    ++	const char *server_sid;
      
      	connect_setup(transport, for_push);
      
    @@ transport.c: static struct ref *handshake(struct transport *transport, int for_p
      	data->version = discover_version(&reader);
      	switch (data->version) {
      	case protocol_v2:
    -+		if (server_feature_v2("trace2-sid", &server_trace2_sid))
    -+			trace2_data_string("trace2", NULL, "server-sid", server_trace2_sid);
    ++		if (server_feature_v2("session-id", &server_sid))
    ++			trace2_data_string("transfer", NULL, "server-sid", server_sid);
      		if (must_list_refs)
      			get_remote_refs(data->fd[1], &reader, &refs, for_push,
      					ref_prefixes,
    @@ transport.c: static struct ref *handshake(struct transport *transport, int for_p
      				 for_push ? REF_NORMAL : 0,
      				 &data->extra_have,
      				 &data->shallow);
    -+		server_trace2_sid = server_feature_value("trace2-sid", &sid_len);
    -+		if (server_trace2_sid) {
    -+			char *server_sid = xstrndup(server_trace2_sid, sid_len);
    -+			trace2_data_string("trace2", NULL, "server-sid", server_sid);
    -+			free(server_sid);
    ++		server_sid = server_feature_value("session-id", &sid_len);
    ++		if (server_sid) {
    ++			char *sid = xstrndup(server_sid, sid_len);
    ++			trace2_data_string("transfer", NULL, "server-sid", sid);
    ++			free(sid);
     +		}
      		break;
      	case protocol_unknown_version:
 8:  11b5b1b54f !  8:  fc9f6c9286 fetch-pack: advertise trace2 SID in capabilities
    @@ Metadata
     Author: Josh Steadmon <steadmon@google.com>
     
      ## Commit message ##
    -    fetch-pack: advertise trace2 SID in capabilities
    +    fetch-pack: advertise session ID in capabilities
     
    -    When trace2 is enabled, the server sent a trace2-sid capability, and
    -    trace2.advertiseSID is true, advertise fetch-pack's own session ID back
    -    to the server.
    +    When the server sent a session-id capability and transfer.advertiseSID
    +    is true, advertise fetch-pack's own session ID back to the server.
     
     
    @@ fetch-pack.c: static int fetch_fsck_objects = -1;
      static int transfer_fsck_objects = -1;
      static int agent_supported;
      static int server_supports_filtering;
    -+static int server_sent_trace2_sid;
    -+static int advertise_trace2_sid;
    ++static int advertise_sid;
      static struct shallow_lock shallow_lock;
      static const char *alternate_shallow_file;
      static struct strbuf fsck_msg_types = STRBUF_INIT;
    @@ fetch-pack.c: static int find_common(struct fetch_negotiator *negotiator,
      			if (deepen_not_ok)      strbuf_addstr(&c, " deepen-not");
      			if (agent_supported)    strbuf_addf(&c, " agent=%s",
      							    git_user_agent_sanitized());
    -+			if (advertise_trace2_sid && server_sent_trace2_sid && trace2_is_enabled())
    -+				strbuf_addf(&c, " trace2-sid=%s", trace2_session_id());
    ++			if (advertise_sid)
    ++				strbuf_addf(&c, " session-id=%s", trace2_session_id());
      			if (args->filter_options.choice)
      				strbuf_addstr(&c, " filter");
      			packet_buf_write(&req_buf, "want %s%s\n", remote_hex, c.buf);
    @@ fetch-pack.c: static struct ref *do_fetch_pack(struct fetch_pack_args *args,
      				      agent_len, agent_feature);
      	}
      
    -+	if (server_supports("trace2-sid"))
    -+		server_sent_trace2_sid = 1;
    ++	if (!server_supports("session-id"))
    ++		advertise_sid = 0;
     +
      	if (server_supports("shallow"))
      		print_verbose(args, _("Server supports %s"), "shallow");
    @@ fetch-pack.c: static int send_fetch_request(struct fetch_negotiator *negotiator,
      		packet_buf_write(&req_buf, "command=fetch");
      	if (server_supports_v2("agent", 0))
      		packet_buf_write(&req_buf, "agent=%s", git_user_agent_sanitized());
    -+	if (advertise_trace2_sid && server_supports_v2("trace2-sid", 0) && trace2_is_enabled())
    -+		packet_buf_write(&req_buf, "trace2-sid=%s", trace2_session_id());
    ++	if (advertise_sid && server_supports_v2("session-id", 0))
    ++		packet_buf_write(&req_buf, "session-id=%s", trace2_session_id());
      	if (args->server_options && args->server_options->nr &&
      	    server_supports_v2("server-option", 1)) {
      		int i;
    @@ fetch-pack.c: static void fetch_pack_config(void)
      	git_config_get_bool("repack.usedeltabaseoffset", &prefer_ofs_delta);
      	git_config_get_bool("fetch.fsckobjects", &fetch_fsck_objects);
      	git_config_get_bool("transfer.fsckobjects", &transfer_fsck_objects);
    -+	git_config_get_bool("trace2.advertisesid", &advertise_trace2_sid);
    ++	git_config_get_bool("transfer.advertisesid", &advertise_sid);
      	if (!uri_protocols.nr) {
      		char *str;
      
 9:  23f44bc904 !  9:  bde9c1d97a upload-pack, serve: log received client trace2 SID
    @@ Metadata
     Author: Josh Steadmon <steadmon@google.com>
     
      ## Commit message ##
    -    upload-pack, serve: log received client trace2 SID
    +    upload-pack, serve: log received client session ID
     
         When upload-pack (protocol v0/v1) or a protocol v2 server receives a
    -    trace2-sid capability from a client, log the received session ID via a
    +    session-id capability from a client, log the received session ID via a
         trace2 data event.
     
    @@ serve.c: static int process_request(void)
      
      	check_algorithm(the_repository, &keys);
      
    -+	if (has_capability(&keys, "trace2-sid", &client_sid))
    -+		trace2_data_string("trace2", NULL, "client-sid", client_sid);
    ++	if (has_capability(&keys, "session-id", &client_sid))
    ++		trace2_data_string("transfer", NULL, "client-sid", client_sid);
     +
      	command->command(the_repository, &keys, &reader);
      
      	strvec_clear(&keys);
     
    - ## t/t5705-trace2-sid-in-capabilities.sh ##
    -@@ t/t5705-trace2-sid-in-capabilities.sh: test_expect_success 'setup repos for trace2 SID capability tests' '
    + ## t/t5705-session-id-in-capabilities.sh ##
    +@@ t/t5705-session-id-in-capabilities.sh: test_expect_success 'setup repos for session ID capability tests' '
      for PROTO in 0 1 2
      do
    - 	test_expect_success "trace2 session IDs not advertised by default (fetch v${PROTO})" '
    + 	test_expect_success "session IDs not advertised by default (fetch v${PROTO})" '
     -		test_when_finished "rm -rf local tr2-client-events" &&
     +		test_when_finished "rm -rf local tr2-client-events tr2-server-events" &&
      		cp -r "$LOCAL_PRISTINE" local &&
    @@ t/t5705-trace2-sid-in-capabilities.sh: test_expect_success 'setup repos for trac
     +		test -z "$(grep \"key\":\"client-sid\" tr2-server-events)"
      	'
      
    - 	test_expect_success "trace2 session IDs not advertised by default (push v${PROTO})" '
    -@@ t/t5705-trace2-sid-in-capabilities.sh: test_expect_success 'enable SID advertisement' '
    + 	test_expect_success "session IDs not advertised by default (push v${PROTO})" '
    +@@ t/t5705-session-id-in-capabilities.sh: test_expect_success 'enable SID advertisement' '
      for PROTO in 0 1 2
      do
    - 	test_expect_success "trace2 session IDs advertised (fetch v${PROTO})" '
    + 	test_expect_success "session IDs advertised (fetch v${PROTO})" '
     -		test_when_finished "rm -rf local tr2-client-events" &&
     +		test_when_finished "rm -rf local tr2-client-events tr2-server-events" &&
      		cp -r "$LOCAL_PRISTINE" local &&
    -+		git -C local config trace2.advertiseSID true &&
      		GIT_TRACE2_EVENT="$(pwd)/tr2-client-events" \
     -		git -c protocol.version=$PROTO -C local fetch origin &&
     -		grep \"key\":\"server-sid\" tr2-client-events
    @@ t/t5705-trace2-sid-in-capabilities.sh: test_expect_success 'enable SID advertise
     +		grep \"key\":\"client-sid\" tr2-server-events
      	'
      
    - 	test_expect_success "trace2 session IDs advertised (push v${PROTO})" '
    + 	test_expect_success "session IDs advertised (push v${PROTO})" '
     
      ## upload-pack.c ##
     @@ upload-pack.c: static void receive_needs(struct upload_pack_data *data,
    @@ upload-pack.c: static void receive_needs(struct upload_pack_data *data,
      		reset_timeout(data->timeout);
      		if (packet_reader_read(reader) != PACKET_READ_NORMAL)
     @@ upload-pack.c: static void receive_needs(struct upload_pack_data *data,
    - 		if (data->allow_filter &&
      		    parse_feature_request(features, "filter"))
      			data->filter_capability_requested = 1;
    -+		if ((arg = parse_feature_value(features, "trace2-sid", &feature_len, NULL)))
    -+		{
    + 
    ++		arg = parse_feature_value(features, "session-id", &feature_len, NULL);
    ++		if (arg) {
     +			char *client_sid = xstrndup(arg, feature_len);
    -+			trace2_data_string("trace2", NULL, "client-sid", client_sid);
    ++			trace2_data_string("transfer", NULL, "client-sid", client_sid);
     +			free(client_sid);
     +		}
    - 
    ++
      		o = parse_object(the_repository, &oid_buf);
      		if (!o) {
    + 			packet_writer_error(&data->writer,
10:  c0b1ffc6d8 ! 10:  012949e7da send-pack: advertise trace2 SID in capabilities
    @@ Metadata
     Author: Josh Steadmon <steadmon@google.com>
     
      ## Commit message ##
    -    send-pack: advertise trace2 SID in capabilities
    +    send-pack: advertise session ID in capabilities
     
    -    When trace2 is enabled, the server sent a trace2-sid capability, and
    -    trace2.advertiseSID is true, advertise send-pack's own session ID back
    -    to the server.
    +    When the server sent a session-id capability and transfer.advertiseSID
    +    is true, advertise send-pack's own session ID back to the server.
     
     
    @@ send-pack.c: int send_pack(struct send_pack_args *args,
      	int use_sideband = 0;
      	int quiet_supported = 0;
      	int agent_supported = 0;
    -+	int server_sent_trace2_sid = 0;
    -+	int advertise_trace2_sid = 0;
    ++	int advertise_sid = 0;
      	int use_atomic = 0;
      	int atomic_supported = 0;
      	int use_push_options = 0;
    @@ send-pack.c: int send_pack(struct send_pack_args *args,
      	const char *push_cert_nonce = NULL;
      	struct packet_reader reader;
      
    -+	git_config_get_bool("trace2.advertisesid", &advertise_trace2_sid);
    ++	git_config_get_bool("transfer.advertisesid", &advertise_sid);
     +
      	/* Does the other end support the reporting? */
      	if (server_supports("report-status-v2"))
    @@ send-pack.c: int send_pack(struct send_pack_args *args,
      		quiet_supported = 1;
      	if (server_supports("agent"))
      		agent_supported = 1;
    -+	if (server_supports("trace2-sid"))
    -+		server_sent_trace2_sid = 1;
    ++	if (!server_supports("session-id"))
    ++		advertise_sid = 0;
      	if (server_supports("no-thin"))
      		args->use_thin_pack = 0;
      	if (server_supports("atomic"))
    @@ send-pack.c: int send_pack(struct send_pack_args *args,
      		strbuf_addf(&cap_buf, " object-format=%s", the_hash_algo->name);
      	if (agent_supported)
      		strbuf_addf(&cap_buf, " agent=%s", git_user_agent_sanitized());
    -+	if (advertise_trace2_sid && server_sent_trace2_sid && trace2_is_enabled())
    -+		strbuf_addf(&cap_buf, " trace2-sid=%s", trace2_session_id());
    ++	if (advertise_sid)
    ++		strbuf_addf(&cap_buf, " session-id=%s", trace2_session_id());
      
      	/*
      	 * NEEDSWORK: why does delete-refs have to be so specific to
11:  c47eddd9df ! 11:  ea2a318f2b receive-pack: log received client trace2 SID
    @@ Metadata
     Author: Josh Steadmon <steadmon@google.com>
     
      ## Commit message ##
    -    receive-pack: log received client trace2 SID
    +    receive-pack: log received client session ID
     
    -    When receive-pack receives a trace2-sid capability from the client, log
    +    When receive-pack receives a session-id capability from the client, log
         the received session ID via a trace2 data event.
     
    @@ builtin/receive-pack.c: static struct command *read_head_info(struct packet_read
      		if (linelen < reader->pktlen) {
      			const char *feature_list = reader->line + linelen + 1;
      			const char *hash = NULL;
    -+			const char *client_trace2_sid;
    ++			const char *client_sid;
      			int len = 0;
      			if (parse_feature_request(feature_list, "report-status"))
      				report_status = 1;
    @@ builtin/receive-pack.c: static struct command *read_head_info(struct packet_read
      			}
      			if (xstrncmpz(the_hash_algo->name, hash, len))
      				die("error: unsupported object format '%s'", hash);
    -+			client_trace2_sid = parse_feature_value(feature_list, "trace2-sid", &len, NULL);
    -+			if (client_trace2_sid) {
    -+				char *client_sid = xstrndup(client_trace2_sid, len);
    -+				trace2_data_string("trace2", NULL, "client-sid", client_sid);
    -+				free(client_sid);
    ++			client_sid = parse_feature_value(feature_list, "session-id", &len, NULL);
    ++			if (client_sid) {
    ++				char *sid = xstrndup(client_sid, len);
    ++				trace2_data_string("transfer", NULL, "client-sid", client_sid);
    ++				free(sid);
     +			}
      		}
      
      		if (!strcmp(reader->line, "push-cert")) {
     
    - ## t/t5705-trace2-sid-in-capabilities.sh ##
    -@@ t/t5705-trace2-sid-in-capabilities.sh: do
    + ## t/t5705-session-id-in-capabilities.sh ##
    +@@ t/t5705-session-id-in-capabilities.sh: do
      	'
      
    - 	test_expect_success "trace2 session IDs not advertised by default (push v${PROTO})" '
    + 	test_expect_success "session IDs not advertised by default (push v${PROTO})" '
     -		test_when_finished "rm -rf local tr2-client-events" &&
     +		test_when_finished "rm -rf local tr2-client-events tr2-server-events" &&
     +		test_when_finished "git -C local push --delete origin new-branch" &&
    @@ t/t5705-trace2-sid-in-capabilities.sh: do
      	'
      done
      
    -@@ t/t5705-trace2-sid-in-capabilities.sh: do
    +@@ t/t5705-session-id-in-capabilities.sh: do
      	'
      
    - 	test_expect_success "trace2 session IDs advertised (push v${PROTO})" '
    + 	test_expect_success "session IDs advertised (push v${PROTO})" '
     -		test_when_finished "rm -rf local tr2-client-events" &&
     +		test_when_finished "rm -rf local tr2-client-events tr2-server-events" &&
     +		test_when_finished "git -C local push --delete origin new-branch" &&
-- 
2.29.2.222.g5d2a92d10f8-goog