From eacf36a4d1d6e83418c02f61e0c418d049000240 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?=
 <avarab@gmail.com>
Date: Thu, 5 Aug 2021 03:25:34 +0200
Subject: [PATCH 01/10] serve: mark has_capability() as static
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The has_capability() function introduced in ed10cb952d3 (serve:
introduce git-serve, 2018-03-15) has never been used anywhere except
serve.c, so let's mark it as static.

It was later changed from "extern" in 554544276a6 (*.[ch]: remove
extern from function declarations using spatch, 2019-04-29), but we
could have simply marked it as "static" instead.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 serve.c | 4 ++--
 serve.h | 4 ----
 2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/serve.c b/serve.c
index f11c0e07c4..7bf5f23ea6 100644
--- a/serve.c
+++ b/serve.c
@@ -156,8 +156,8 @@ static int is_command(const char *key, struct protocol_capability **command)
 	return 0;
 }
 
-int has_capability(const struct strvec *keys, const char *capability,
-		   const char **value)
+static int has_capability(const struct strvec *keys, const char *capability,
+			  const char **value)
 {
 	int i;
 	for (i = 0; i < keys->nr; i++) {
diff --git a/serve.h b/serve.h
index fc2683e24d..56da77a87a 100644
--- a/serve.h
+++ b/serve.h
@@ -1,10 +1,6 @@
 #ifndef SERVE_H
 #define SERVE_H
 
-struct strvec;
-int has_capability(const struct strvec *keys, const char *capability,
-		   const char **value);
-
 struct serve_options {
 	unsigned advertise_capabilities;
 	unsigned stateless_rpc;

From 9b1cdd334d458a063dd43058fca551b7ab57e333 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?=
 <avarab@gmail.com>
Date: Thu, 5 Aug 2021 03:25:35 +0200
Subject: [PATCH 02/10] transport: rename "fetch" in transport_vtable to
 "fetch_refs"
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Rename the "fetch" member of the transport_vtable to "fetch_refs" for
consistency with the existing "push_refs". Neither of them just push
"refs" but refs and objects, but having the two match makes the code
more readable than having it be inconsistent, especially since
"fetch_refs" is a lot easier to grep for than "fetch".

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 transport-helper.c   | 8 ++++----
 transport-internal.h | 2 +-
 transport.c          | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/transport-helper.c b/transport-helper.c
index 4be035edb8..8d445a8f3e 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -671,8 +671,8 @@ static int connect_helper(struct transport *transport, const char *name,
 static struct ref *get_refs_list_using_list(struct transport *transport,
 					    int for_push);
 
-static int fetch(struct transport *transport,
-		 int nr_heads, struct ref **to_fetch)
+static int fetch_refs(struct transport *transport,
+		      int nr_heads, struct ref **to_fetch)
 {
 	struct helper_data *data = transport->data;
 	int i, count;
@@ -681,7 +681,7 @@ static int fetch(struct transport *transport,
 
 	if (process_connect(transport, 0)) {
 		do_take_over(transport);
-		return transport->vtable->fetch(transport, nr_heads, to_fetch);
+		return transport->vtable->fetch_refs(transport, nr_heads, to_fetch);
 	}
 
 	/*
@@ -1263,7 +1263,7 @@ static struct ref *get_refs_list_using_list(struct transport *transport,
 static struct transport_vtable vtable = {
 	set_helper_option,
 	get_refs_list,
-	fetch,
+	fetch_refs,
 	push_refs,
 	connect_helper,
 	release_helper
diff --git a/transport-internal.h b/transport-internal.h
index b60f1ba907..c4ca0b733a 100644
--- a/transport-internal.h
+++ b/transport-internal.h
@@ -34,7 +34,7 @@ struct transport_vtable {
 	 * get_refs_list(), it should set the old_sha1 fields in the
 	 * provided refs now.
 	 **/
-	int (*fetch)(struct transport *transport, int refs_nr, struct ref **refs);
+	int (*fetch_refs)(struct transport *transport, int refs_nr, struct ref **refs);
 
 	/**
 	 * Push the objects and refs. Send the necessary objects, and
diff --git a/transport.c b/transport.c
index 17e9629710..3e8a27b032 100644
--- a/transport.c
+++ b/transport.c
@@ -1453,7 +1453,7 @@ int transport_fetch_refs(struct transport *transport, struct ref *refs)
 			heads[nr_heads++] = rm;
 	}
 
-	rc = transport->vtable->fetch(transport, nr_heads, heads);
+	rc = transport->vtable->fetch_refs(transport, nr_heads, heads);
 
 	free(heads);
 	return rc;

From 1fd88224a310f91c7ccac480473df40979d91f92 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?=
 <avarab@gmail.com>
Date: Thu, 5 Aug 2021 03:25:36 +0200
Subject: [PATCH 03/10] transport: use designated initializers
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Change the assignments to the various transport_vtables to use
designated initializers, this makes the code easier to read and
maintain.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 transport-helper.c | 12 ++++++------
 transport.c        | 30 ++++++++++++------------------
 2 files changed, 18 insertions(+), 24 deletions(-)

diff --git a/transport-helper.c b/transport-helper.c
index 8d445a8f3e..e8dbdd1153 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -1261,12 +1261,12 @@ static struct ref *get_refs_list_using_list(struct transport *transport,
 }
 
 static struct transport_vtable vtable = {
-	set_helper_option,
-	get_refs_list,
-	fetch_refs,
-	push_refs,
-	connect_helper,
-	release_helper
+	.set_option	= set_helper_option,
+	.get_refs_list	= get_refs_list,
+	.fetch_refs	= fetch_refs,
+	.push_refs	= push_refs,
+	.connect	= connect_helper,
+	.disconnect	= release_helper
 };
 
 int transport_helper_init(struct transport *transport, const char *name)
diff --git a/transport.c b/transport.c
index 3e8a27b032..f9400b9b0b 100644
--- a/transport.c
+++ b/transport.c
@@ -883,12 +883,10 @@ static int disconnect_git(struct transport *transport)
 }
 
 static struct transport_vtable taken_over_vtable = {
-	NULL,
-	get_refs_via_connect,
-	fetch_refs_via_pack,
-	git_transport_push,
-	NULL,
-	disconnect_git
+	.get_refs_list	= get_refs_via_connect,
+	.fetch_refs	= fetch_refs_via_pack,
+	.push_refs	= git_transport_push,
+	.disconnect	= disconnect_git
 };
 
 void transport_take_over(struct transport *transport,
@@ -1032,21 +1030,17 @@ void transport_check_allowed(const char *type)
 }
 
 static struct transport_vtable bundle_vtable = {
-	NULL,
-	get_refs_from_bundle,
-	fetch_refs_from_bundle,
-	NULL,
-	NULL,
-	close_bundle
+	.get_refs_list	= get_refs_from_bundle,
+	.fetch_refs	= fetch_refs_from_bundle,
+	.disconnect	= close_bundle
 };
 
 static struct transport_vtable builtin_smart_vtable = {
-	NULL,
-	get_refs_via_connect,
-	fetch_refs_via_pack,
-	git_transport_push,
-	connect_git,
-	disconnect_git
+	.get_refs_list	= get_refs_via_connect,
+	.fetch_refs	= fetch_refs_via_pack,
+	.push_refs	= git_transport_push,
+	.connect	= connect_git,
+	.disconnect	= disconnect_git
 };
 
 struct transport *transport_get(struct remote *remote, const char *url)

From 85baaed4757860eb54e6451be305bfb7ef863646 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?=
 <avarab@gmail.com>
Date: Thu, 5 Aug 2021 03:25:37 +0200
Subject: [PATCH 04/10] serve: use designated initializers
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Change the declaration of the protocol_capability struct to use
designated initializers, this makes this more verbose now, but a
follow-up commit will add a new field. At that point these lines would
be too dense to be on one line comfortably.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 serve.c | 38 +++++++++++++++++++++++++++++++-------
 1 file changed, 31 insertions(+), 7 deletions(-)

diff --git a/serve.c b/serve.c
index 7bf5f23ea6..33d00c8c63 100644
--- a/serve.c
+++ b/serve.c
@@ -73,13 +73,37 @@ struct protocol_capability {
 };
 
 static struct protocol_capability capabilities[] = {
-	{ "agent", agent_advertise, NULL },
-	{ "ls-refs", ls_refs_advertise, ls_refs },
-	{ "fetch", upload_pack_advertise, upload_pack_v2 },
-	{ "server-option", always_advertise, NULL },
-	{ "object-format", object_format_advertise, NULL },
-	{ "session-id", session_id_advertise, NULL },
-	{ "object-info", always_advertise, cap_object_info },
+	{
+		.name = "agent",
+		.advertise = agent_advertise,
+	},
+	{
+		.name = "ls-refs",
+		.advertise = ls_refs_advertise,
+		.command = ls_refs,
+	},
+	{
+		.name = "fetch",
+		.advertise = upload_pack_advertise,
+		.command = upload_pack_v2,
+	},
+	{
+		.name = "server-option",
+		.advertise = always_advertise,
+	},
+	{
+		.name = "object-format",
+		.advertise = object_format_advertise,
+	},
+	{
+		.name = "session-id",
+		.advertise = session_id_advertise,
+	},
+	{
+		.name = "object-info",
+		.advertise = always_advertise,
+		.command = cap_object_info,
+	},
 };
 
 static void advertise_capabilities(void)

From 28a592e4f4870bdd444675b7240920d0879a9c1b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?=
 <avarab@gmail.com>
Date: Thu, 5 Aug 2021 03:25:38 +0200
Subject: [PATCH 05/10] serve.[ch]: don't pass "struct strvec *keys" to
 commands
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The serve.c API added in ed10cb952d3 (serve: introduce git-serve,
2018-03-15) was passing in the raw capabilities "keys", but nothing
downstream of it ever used them.

Let's remove that code because it's not needed. If we do end up
needing to pass information about the advertisement in the future
it'll make more sense to have serve.c parse the capabilities keys and
pass the result of its parsing, rather than expecting expecting its
API users to parse the same keys again.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 ls-refs.c       | 3 +--
 ls-refs.h       | 4 +---
 protocol-caps.c | 3 +--
 protocol-caps.h | 4 +---
 serve.c         | 9 +++------
 upload-pack.c   | 3 +--
 upload-pack.h   | 4 +---
 7 files changed, 9 insertions(+), 21 deletions(-)

diff --git a/ls-refs.c b/ls-refs.c
index 88f6c3f60d..a1a0250607 100644
--- a/ls-refs.c
+++ b/ls-refs.c
@@ -138,8 +138,7 @@ static int ls_refs_config(const char *var, const char *value, void *data)
 	return parse_hide_refs_config(var, value, "uploadpack");
 }
 
-int ls_refs(struct repository *r, struct strvec *keys,
-	    struct packet_reader *request)
+int ls_refs(struct repository *r, struct packet_reader *request)
 {
 	struct ls_refs_data data;
 
diff --git a/ls-refs.h b/ls-refs.h
index a99e4be0bd..e2243a547b 100644
--- a/ls-refs.h
+++ b/ls-refs.h
@@ -2,10 +2,8 @@
 #define LS_REFS_H
 
 struct repository;
-struct strvec;
 struct packet_reader;
-int ls_refs(struct repository *r, struct strvec *keys,
-	    struct packet_reader *request);
+int ls_refs(struct repository *r, struct packet_reader *request);
 int ls_refs_advertise(struct repository *r, struct strbuf *value);
 
 #endif /* LS_REFS_H */
diff --git a/protocol-caps.c b/protocol-caps.c
index 13a9e63a04..4b345c5504 100644
--- a/protocol-caps.c
+++ b/protocol-caps.c
@@ -74,8 +74,7 @@ static void send_info(struct repository *r, struct packet_writer *writer,
 	}
 }
 
-int cap_object_info(struct repository *r, struct strvec *keys,
-		    struct packet_reader *request)
+int cap_object_info(struct repository *r, struct packet_reader *request)
 {
 	struct requested_info info;
 	struct packet_writer writer;
diff --git a/protocol-caps.h b/protocol-caps.h
index 0a9f49df11..15c4550360 100644
--- a/protocol-caps.h
+++ b/protocol-caps.h
@@ -2,9 +2,7 @@
 #define PROTOCOL_CAPS_H
 
 struct repository;
-struct strvec;
 struct packet_reader;
-int cap_object_info(struct repository *r, struct strvec *keys,
-		    struct packet_reader *request);
+int cap_object_info(struct repository *r, struct packet_reader *request);
 
 #endif /* PROTOCOL_CAPS_H */
diff --git a/serve.c b/serve.c
index 33d00c8c63..967bf17d62 100644
--- a/serve.c
+++ b/serve.c
@@ -60,16 +60,13 @@ struct protocol_capability {
 
 	/*
 	 * Function called when a client requests the capability as a command.
-	 * The function will be provided the capabilities requested via 'keys'
-	 * as well as a struct packet_reader 'request' which the command should
+	 * Will be provided a struct packet_reader 'request' which it should
 	 * use to read the command specific part of the request.  Every command
 	 * MUST read until a flush packet is seen before sending a response.
 	 *
 	 * This field should be NULL for capabilities which are not commands.
 	 */
-	int (*command)(struct repository *r,
-		       struct strvec *keys,
-		       struct packet_reader *request);
+	int (*command)(struct repository *r, struct packet_reader *request);
 };
 
 static struct protocol_capability capabilities[] = {
@@ -294,7 +291,7 @@ static int process_request(void)
 	if (has_capability(&keys, "session-id", &client_sid))
 		trace2_data_string("transfer", NULL, "client-sid", client_sid);
 
-	command->command(the_repository, &keys, &reader);
+	command->command(the_repository, &reader);
 
 	strvec_clear(&keys);
 	return 0;
diff --git a/upload-pack.c b/upload-pack.c
index 297b76fcb4..ed60a9abd6 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -1655,8 +1655,7 @@ enum fetch_state {
 	FETCH_DONE,
 };
 
-int upload_pack_v2(struct repository *r, struct strvec *keys,
-		   struct packet_reader *request)
+int upload_pack_v2(struct repository *r, struct packet_reader *request)
 {
 	enum fetch_state state = FETCH_PROCESS_ARGS;
 	struct upload_pack_data data;
diff --git a/upload-pack.h b/upload-pack.h
index 27ddcdc6cb..63e3252c98 100644
--- a/upload-pack.h
+++ b/upload-pack.h
@@ -11,10 +11,8 @@ struct upload_pack_options {
 void upload_pack(struct upload_pack_options *options);
 
 struct repository;
-struct strvec;
 struct packet_reader;
-int upload_pack_v2(struct repository *r, struct strvec *keys,
-		   struct packet_reader *request);
+int upload_pack_v2(struct repository *r, struct packet_reader *request);
 
 struct strbuf;
 int upload_pack_advertise(struct repository *r,

From eea7f7a977c61f313774d591ed54ec9d7345fdaf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?=
 <avarab@gmail.com>
Date: Thu, 5 Aug 2021 03:25:39 +0200
Subject: [PATCH 06/10] serve: move transfer.advertiseSID check into
 session_id_advertise()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

In 6b5b6e422ee (serve: advertise session ID in v2 capabilities,
2020-11-11) the check for transfer.advertiseSID was added to the
beginning of the main serve() loop. Thus on startup of the server we'd
populate it.

Let's instead use an explicit lazy initialization pattern in
session_id_advertise() itself, we'll still look the config up only
once per-process, but by moving it out of serve() itself the further
changing of that routine becomes easier.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 serve.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/serve.c b/serve.c
index 967bf17d62..2682999133 100644
--- a/serve.c
+++ b/serve.c
@@ -9,7 +9,7 @@
 #include "serve.h"
 #include "upload-pack.h"
 
-static int advertise_sid;
+static int advertise_sid = -1;
 
 static int always_advertise(struct repository *r,
 			    struct strbuf *value)
@@ -35,6 +35,9 @@ static int object_format_advertise(struct repository *r,
 
 static int session_id_advertise(struct repository *r, struct strbuf *value)
 {
+	if (advertise_sid == -1 &&
+	    git_config_get_bool("transfer.advertisesid", &advertise_sid))
+		advertise_sid = 0;
 	if (!advertise_sid)
 		return 0;
 	if (value)
@@ -300,8 +303,6 @@ static int process_request(void)
 /* Main serve loop for protocol version 2 */
 void serve(struct serve_options *options)
 {
-	git_config_get_bool("transfer.advertisesid", &advertise_sid);
-
 	if (options->advertise_capabilities || !options->stateless_rpc) {
 		/* serve by default supports v2 */
 		packet_write_fmt(1, "version 2\n");

From 5befe8a1f14e2429fee526acc8dcc23039f5193b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?=
 <avarab@gmail.com>
Date: Thu, 5 Aug 2021 03:25:40 +0200
Subject: [PATCH 07/10] serve.c: move version line to advertise_capabilities()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The advertise_capabilities() is only called from serve() and we always
emit this version line before it. In a subsequent commit I'll make
builtin/upload-pack.c sometimes call advertise_capabilities()
directly, so it'll make sense to have this line emitted by
advertise_capabilities(), not serve() itself.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 serve.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/serve.c b/serve.c
index 2682999133..412c2cd131 100644
--- a/serve.c
+++ b/serve.c
@@ -112,6 +112,9 @@ static void advertise_capabilities(void)
 	struct strbuf value = STRBUF_INIT;
 	int i;
 
+	/* serve by default supports v2 */
+	packet_write_fmt(1, "version 2\n");
+
 	for (i = 0; i < ARRAY_SIZE(capabilities); i++) {
 		struct protocol_capability *c = &capabilities[i];
 
@@ -304,9 +307,6 @@ static int process_request(void)
 void serve(struct serve_options *options)
 {
 	if (options->advertise_capabilities || !options->stateless_rpc) {
-		/* serve by default supports v2 */
-		packet_write_fmt(1, "version 2\n");
-
 		advertise_capabilities();
 		/*
 		 * If only the list of capabilities was requested exit

From 760486a1f7a141b0d50b1c9c709ac1882968955c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?=
 <avarab@gmail.com>
Date: Thu, 5 Aug 2021 03:25:41 +0200
Subject: [PATCH 08/10] {upload,receive}-pack tests: add --advertise-refs tests
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The --advertise-refs option had no explicit tests of its own, only
other http tests that would fail at a distance if it it was
broken. Let's test its behavior explicitly.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 t/t5555-http-smart-common.sh | 147 +++++++++++++++++++++++++++++++++++
 1 file changed, 147 insertions(+)
 create mode 100755 t/t5555-http-smart-common.sh

diff --git a/t/t5555-http-smart-common.sh b/t/t5555-http-smart-common.sh
new file mode 100755
index 0000000000..b813099ed2
--- /dev/null
+++ b/t/t5555-http-smart-common.sh
@@ -0,0 +1,147 @@
+#!/bin/sh
+
+test_description='test functionality common to smart fetch & push'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	test_commit --no-tag initial
+'
+
+test_expect_success 'git upload-pack --advertise-refs' '
+	cat >expect <<-EOF &&
+	$(git rev-parse HEAD) HEAD
+	$(git rev-parse HEAD) $(git symbolic-ref HEAD)
+	0000
+	EOF
+
+	# We only care about GIT_PROTOCOL, not GIT_TEST_PROTOCOL_VERSION
+	sane_unset GIT_PROTOCOL &&
+	GIT_TEST_PROTOCOL_VERSION=2 \
+	git upload-pack --advertise-refs . >out 2>err &&
+
+	test-tool pkt-line unpack <out >actual &&
+	test_must_be_empty err &&
+	test_cmp actual expect &&
+
+	# The --advertise-refs alias works
+	git upload-pack --advertise-refs . >out 2>err &&
+
+	test-tool pkt-line unpack <out >actual &&
+	test_must_be_empty err &&
+	test_cmp actual expect
+'
+
+test_expect_success 'git upload-pack --advertise-refs: v0' '
+	# With no specified protocol
+	cat >expect <<-EOF &&
+	$(git rev-parse HEAD) HEAD
+	$(git rev-parse HEAD) $(git symbolic-ref HEAD)
+	0000
+	EOF
+
+	git upload-pack --advertise-refs . >out 2>err &&
+	test-tool pkt-line unpack <out >actual &&
+	test_must_be_empty err &&
+	test_cmp actual expect &&
+
+	# With explicit v0
+	GIT_PROTOCOL=version=0 \
+	git upload-pack --advertise-refs . >out 2>err &&
+	test-tool pkt-line unpack <out >actual 2>err &&
+	test_must_be_empty err &&
+	test_cmp actual expect
+
+'
+
+test_expect_success 'git receive-pack --advertise-refs: v0' '
+	# With no specified protocol
+	cat >expect <<-EOF &&
+	$(git rev-parse HEAD) $(git symbolic-ref HEAD)
+	0000
+	EOF
+
+	git receive-pack --advertise-refs . >out 2>err &&
+	test-tool pkt-line unpack <out >actual &&
+	test_must_be_empty err &&
+	test_cmp actual expect &&
+
+	# With explicit v0
+	GIT_PROTOCOL=version=0 \
+	git receive-pack --advertise-refs . >out 2>err &&
+	test-tool pkt-line unpack <out >actual 2>err &&
+	test_must_be_empty err &&
+	test_cmp actual expect
+
+'
+
+test_expect_success 'git upload-pack --advertise-refs: v1' '
+	# With no specified protocol
+	cat >expect <<-EOF &&
+	version 1
+	$(git rev-parse HEAD) HEAD
+	$(git rev-parse HEAD) $(git symbolic-ref HEAD)
+	0000
+	EOF
+
+	GIT_PROTOCOL=version=1 \
+	git upload-pack --advertise-refs . >out &&
+
+	test-tool pkt-line unpack <out >actual 2>err &&
+	test_must_be_empty err &&
+	test_cmp actual expect
+'
+
+test_expect_success 'git receive-pack --advertise-refs: v1' '
+	# With no specified protocol
+	cat >expect <<-EOF &&
+	version 1
+	$(git rev-parse HEAD) $(git symbolic-ref HEAD)
+	0000
+	EOF
+
+	GIT_PROTOCOL=version=1 \
+	git receive-pack --advertise-refs . >out &&
+
+	test-tool pkt-line unpack <out >actual 2>err &&
+	test_must_be_empty err &&
+	test_cmp actual expect
+'
+
+test_expect_success 'git upload-pack --advertise-refs: v2' '
+	cat >expect <<-EOF &&
+	version 2
+	agent=FAKE
+	ls-refs=unborn
+	fetch=shallow wait-for-done
+	server-option
+	object-format=$(test_oid algo)
+	object-info
+	0000
+	EOF
+
+	GIT_PROTOCOL=version=2 \
+	GIT_USER_AGENT=FAKE \
+	git upload-pack --advertise-refs . >out 2>err &&
+
+	test-tool pkt-line unpack <out >actual &&
+	test_must_be_empty err &&
+	test_cmp actual expect
+'
+
+test_expect_success 'git receive-pack --advertise-refs: v2' '
+	# There is no v2 yet for receive-pack, implicit v0
+	cat >expect <<-EOF &&
+	$(git rev-parse HEAD) $(git symbolic-ref HEAD)
+	0000
+	EOF
+
+	GIT_PROTOCOL=version=2 \
+	git receive-pack --advertise-refs . >out 2>err &&
+
+	test-tool pkt-line unpack <out >actual &&
+	test_must_be_empty err &&
+	test_cmp actual expect
+'
+
+test_done

From f234da80197b3115cd3c280e98d3393a884a9327 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?=
 <avarab@gmail.com>
Date: Thu, 5 Aug 2021 03:25:42 +0200
Subject: [PATCH 09/10] serve.[ch]: remove "serve_options", split up
 --advertise-refs code
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The "advertise capabilities" mode of serve.c added in
ed10cb952d3 (serve: introduce git-serve, 2018-03-15) is only used by
the http-backend.c to call {upload,receive}-pack with the
--advertise-refs parameter. See 42526b478e3 (Add stateless RPC options
to upload-pack, receive-pack, 2009-10-30).

Let's just make cmd_upload_pack() take the two (v2) or three (v2)
parameters the the v2/v1 servicing functions need directly, and pass
those in via the function signature. The logic of whether daemon mode
is implied by the timeout belongs in the v1 function (only used
there).

Once we split up the "advertise v2 refs" from "serve v2 request" it
becomes clear that v2 never cared about those in combination. The only
time it mattered was for v1 to emit its ref advertisement, in that
case we wanted to emit the smart-http-only "no-done" capability.

Since we only do that in the --advertise-refs codepath let's just have
it set "do_done" itself in v1's upload_pack() just before send_ref(),
at that point --advertise-refs and --stateless-rpc in combination are
redundant (the only user is get_info_refs() in http-backend.c), so we
can just pass in --advertise-refs only.

Since we need to touch all the serve() and advertise_capabilities()
codepaths let's rename them to less clever and obvious names, it's
been suggested numerous times, the latest of which is [1]'s suggestion
for protocol_v2_serve_loop(). Let's go with that.

1. https://lore.kernel.org/git/CAFQ2z_NyGb8rju5CKzmo6KhZXD0Dp21u-BbyCb2aNxLEoSPRJw@mail.gmail.com/

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 builtin/upload-pack.c    | 25 ++++++++++++-------------
 http-backend.c           |  2 +-
 serve.c                  | 18 +++++-------------
 serve.h                  |  8 ++------
 t/helper/test-serve-v2.c | 14 +++++++++-----
 upload-pack.c            | 18 +++++++++++-------
 upload-pack.h            | 10 ++--------
 7 files changed, 42 insertions(+), 53 deletions(-)

diff --git a/builtin/upload-pack.c b/builtin/upload-pack.c
index 6da8fa2607..8506030a64 100644
--- a/builtin/upload-pack.c
+++ b/builtin/upload-pack.c
@@ -16,16 +16,17 @@ int cmd_upload_pack(int argc, const char **argv, const char *prefix)
 {
 	const char *dir;
 	int strict = 0;
-	struct upload_pack_options opts = { 0 };
-	struct serve_options serve_opts = SERVE_OPTIONS_INIT;
+	int advertise_refs = 0;
+	int stateless_rpc = 0;
+	int timeout = 0;
 	struct option options[] = {
-		OPT_BOOL(0, "stateless-rpc", &opts.stateless_rpc,
+		OPT_BOOL(0, "stateless-rpc", &stateless_rpc,
 			 N_("quit after a single request/response exchange")),
-		OPT_BOOL(0, "advertise-refs", &opts.advertise_refs,
+		OPT_BOOL(0, "advertise-refs", &advertise_refs,
 			 N_("exit immediately after initial ref advertisement")),
 		OPT_BOOL(0, "strict", &strict,
 			 N_("do not try <directory>/.git/ if <directory> is no Git directory")),
-		OPT_INTEGER(0, "timeout", &opts.timeout,
+		OPT_INTEGER(0, "timeout", &timeout,
 			    N_("interrupt transfer after <n> seconds of inactivity")),
 		OPT_END()
 	};
@@ -38,9 +39,6 @@ int cmd_upload_pack(int argc, const char **argv, const char *prefix)
 	if (argc != 1)
 		usage_with_options(upload_pack_usage, options);
 
-	if (opts.timeout)
-		opts.daemon_mode = 1;
-
 	setup_path();
 
 	dir = argv[0];
@@ -50,21 +48,22 @@ int cmd_upload_pack(int argc, const char **argv, const char *prefix)
 
 	switch (determine_protocol_version_server()) {
 	case protocol_v2:
-		serve_opts.advertise_capabilities = opts.advertise_refs;
-		serve_opts.stateless_rpc = opts.stateless_rpc;
-		serve(&serve_opts);
+		if (advertise_refs)
+			protocol_v2_advertise_capabilities();
+		else
+			protocol_v2_serve_loop(stateless_rpc);
 		break;
 	case protocol_v1:
 		/*
 		 * v1 is just the original protocol with a version string,
 		 * so just fall through after writing the version string.
 		 */
-		if (opts.advertise_refs || !opts.stateless_rpc)
+		if (advertise_refs || !stateless_rpc)
 			packet_write_fmt(1, "version 1\n");
 
 		/* fallthrough */
 	case protocol_v0:
-		upload_pack(&opts);
+		upload_pack(advertise_refs, stateless_rpc, timeout);
 		break;
 	case protocol_unknown_version:
 		BUG("unknown protocol version");
diff --git a/http-backend.c b/http-backend.c
index b329bf63f0..d37463cec8 100644
--- a/http-backend.c
+++ b/http-backend.c
@@ -534,7 +534,7 @@ static void get_info_refs(struct strbuf *hdr, char *arg)
 
 	if (service_name) {
 		const char *argv[] = {NULL /* service name */,
-			"--stateless-rpc", "--advertise-refs",
+			"--advertise-refs",
 			".", NULL};
 		struct rpc_service *svc = select_service(hdr, service_name);
 
diff --git a/serve.c b/serve.c
index 412c2cd131..1817edc7f5 100644
--- a/serve.c
+++ b/serve.c
@@ -106,7 +106,7 @@ static struct protocol_capability capabilities[] = {
 	},
 };
 
-static void advertise_capabilities(void)
+void protocol_v2_advertise_capabilities(void)
 {
 	struct strbuf capability = STRBUF_INIT;
 	struct strbuf value = STRBUF_INIT;
@@ -303,24 +303,16 @@ static int process_request(void)
 	return 0;
 }
 
-/* Main serve loop for protocol version 2 */
-void serve(struct serve_options *options)
+void protocol_v2_serve_loop(int stateless_rpc)
 {
-	if (options->advertise_capabilities || !options->stateless_rpc) {
-		advertise_capabilities();
-		/*
-		 * If only the list of capabilities was requested exit
-		 * immediately after advertising capabilities
-		 */
-		if (options->advertise_capabilities)
-			return;
-	}
+	if (!stateless_rpc)
+		protocol_v2_advertise_capabilities();
 
 	/*
 	 * If stateless-rpc was requested then exit after
 	 * a single request/response exchange
 	 */
-	if (options->stateless_rpc) {
+	if (stateless_rpc) {
 		process_request();
 	} else {
 		for (;;)
diff --git a/serve.h b/serve.h
index 56da77a87a..f946cf904a 100644
--- a/serve.h
+++ b/serve.h
@@ -1,11 +1,7 @@
 #ifndef SERVE_H
 #define SERVE_H
 
-struct serve_options {
-	unsigned advertise_capabilities;
-	unsigned stateless_rpc;
-};
-#define SERVE_OPTIONS_INIT { 0 }
-void serve(struct serve_options *options);
+void protocol_v2_advertise_capabilities(void);
+void protocol_v2_serve_loop(int stateless_rpc);
 
 #endif /* SERVE_H */
diff --git a/t/helper/test-serve-v2.c b/t/helper/test-serve-v2.c
index aee35e5aef..28e905afc3 100644
--- a/t/helper/test-serve-v2.c
+++ b/t/helper/test-serve-v2.c
@@ -10,12 +10,12 @@ static char const * const serve_usage[] = {
 
 int cmd__serve_v2(int argc, const char **argv)
 {
-	struct serve_options opts = SERVE_OPTIONS_INIT;
-
+	int stateless_rpc = 0;
+	int advertise_capabilities = 0;
 	struct option options[] = {
-		OPT_BOOL(0, "stateless-rpc", &opts.stateless_rpc,
+		OPT_BOOL(0, "stateless-rpc", &stateless_rpc,
 			 N_("quit after a single request/response exchange")),
-		OPT_BOOL(0, "advertise-capabilities", &opts.advertise_capabilities,
+		OPT_BOOL(0, "advertise-capabilities", &advertise_capabilities,
 			 N_("exit immediately after advertising capabilities")),
 		OPT_END()
 	};
@@ -25,7 +25,11 @@ int cmd__serve_v2(int argc, const char **argv)
 	argc = parse_options(argc, argv, prefix, options, serve_usage,
 			     PARSE_OPT_KEEP_DASHDASH |
 			     PARSE_OPT_KEEP_UNKNOWN);
-	serve(&opts);
+
+	if (advertise_capabilities)
+		protocol_v2_advertise_capabilities();
+	else
+		protocol_v2_serve_loop(stateless_rpc);
 
 	return 0;
 }
diff --git a/upload-pack.c b/upload-pack.c
index ed60a9abd6..fc38f04d98 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -1214,7 +1214,7 @@ static int send_ref(const char *refname, const struct object_id *oid,
 				     " allow-tip-sha1-in-want" : "",
 			     (data->allow_uor & ALLOW_REACHABLE_SHA1) ?
 				     " allow-reachable-sha1-in-want" : "",
-			     data->stateless_rpc ? " no-done" : "",
+			     data->no_done ? " no-done" : "",
 			     symref_info.buf,
 			     data->allow_filter ? " filter" : "",
 			     session_id.buf,
@@ -1329,7 +1329,8 @@ static int upload_pack_config(const char *var, const char *value, void *cb_data)
 	return parse_hide_refs_config(var, value, "uploadpack");
 }
 
-void upload_pack(struct upload_pack_options *options)
+void upload_pack(const int advertise_refs, const int stateless_rpc,
+		 const int timeout)
 {
 	struct packet_reader reader;
 	struct upload_pack_data data;
@@ -1338,14 +1339,17 @@ void upload_pack(struct upload_pack_options *options)
 
 	git_config(upload_pack_config, &data);
 
-	data.stateless_rpc = options->stateless_rpc;
-	data.daemon_mode = options->daemon_mode;
-	data.timeout = options->timeout;
+	data.stateless_rpc = stateless_rpc;
+	data.timeout = timeout;
+	if (data.timeout)
+		data.daemon_mode = 1;
 
 	head_ref_namespaced(find_symref, &data.symref);
 
-	if (options->advertise_refs || !data.stateless_rpc) {
+	if (advertise_refs || !data.stateless_rpc) {
 		reset_timeout(data.timeout);
+		if (advertise_refs)
+			data.no_done = 1;
 		head_ref_namespaced(send_ref, &data);
 		for_each_namespaced_ref(send_ref, &data);
 		advertise_shallow_grafts(1);
@@ -1355,7 +1359,7 @@ void upload_pack(struct upload_pack_options *options)
 		for_each_namespaced_ref(check_ref, NULL);
 	}
 
-	if (!options->advertise_refs) {
+	if (!advertise_refs) {
 		packet_reader_init(&reader, 0, NULL, 0,
 				   PACKET_READ_CHOMP_NEWLINE |
 				   PACKET_READ_DIE_ON_ERR_PACKET);
diff --git a/upload-pack.h b/upload-pack.h
index 63e3252c98..d6ee25ea98 100644
--- a/upload-pack.h
+++ b/upload-pack.h
@@ -1,14 +1,8 @@
 #ifndef UPLOAD_PACK_H
 #define UPLOAD_PACK_H
 
-struct upload_pack_options {
-	int stateless_rpc;
-	int advertise_refs;
-	unsigned int timeout;
-	int daemon_mode;
-};
-
-void upload_pack(struct upload_pack_options *options);
+void upload_pack(const int advertise_refs, const int stateless_rpc,
+		 const int timeout);
 
 struct repository;
 struct packet_reader;

From 98e2d9d6f7dc1aff61e99a1daed98e18c7c8526b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?=
 <avarab@gmail.com>
Date: Thu, 5 Aug 2021 03:25:43 +0200
Subject: [PATCH 10/10] upload-pack: document and rename --advertise-refs
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The --advertise-refs documentation in git-upload-pack added in
9812f2136b3 (upload-pack.c: use parse-options API, 2016-05-31) hasn't
been entirely true ever since v2 support was implemented in
e52449b6722 (connect: request remote refs using v2, 2018-03-15). Under
v2 we don't advertise the refs at all, but rather dump the
capabilities header.

This option has always been an obscure internal implementation detail,
it wasn't even documented for git-receive-pack. Since it has exactly
one user let's rename it to --http-backend-info-refs, which is more
accurate and points the reader in the right direction. Let's also
cross-link this from the protocol v1 and v2 documentation.

I'm retaining a hidden --advertise-refs alias in case there's any
external users of this, and making both options hidden to the bash
completion (as with most other internal-only options).

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Documentation/git-receive-pack.txt        |  5 +++++
 Documentation/git-upload-pack.txt         | 12 ++++++++----
 Documentation/technical/http-protocol.txt |  3 +++
 Documentation/technical/protocol-v2.txt   |  3 +++
 builtin/receive-pack.c                    |  3 ++-
 builtin/upload-pack.c                     |  5 +++--
 http-backend.c                            |  2 +-
 t/t5555-http-smart-common.sh              | 14 ++++++++++++++
 8 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/Documentation/git-receive-pack.txt b/Documentation/git-receive-pack.txt
index 25702ed730..014a78409b 100644
--- a/Documentation/git-receive-pack.txt
+++ b/Documentation/git-receive-pack.txt
@@ -41,6 +41,11 @@ OPTIONS
 <directory>::
 	The repository to sync into.
 
+--http-backend-info-refs::
+	Used by linkgit:git-http-backend[1] to serve up
+	`$GIT_URL/info/refs?service=git-receive-pack` requests. See
+	`--http-backend-info-refs` in linkgit:git-upload-pack[1].
+
 PRE-RECEIVE HOOK
 ----------------
 Before any ref is updated, if $GIT_DIR/hooks/pre-receive file exists
diff --git a/Documentation/git-upload-pack.txt b/Documentation/git-upload-pack.txt
index 9822c1eb1a..739416ec83 100644
--- a/Documentation/git-upload-pack.txt
+++ b/Documentation/git-upload-pack.txt
@@ -36,10 +36,14 @@ OPTIONS
 	This fits with the HTTP POST request processing model where
 	a program may read the request, write a response, and must exit.
 
---advertise-refs::
-	Only the initial ref advertisement is output, and the program exits
-	immediately. This fits with the HTTP GET request model, where
-	no request content is received but a response must be produced.
+--http-backend-info-refs::
+	Used by linkgit:git-http-backend[1] to serve up
+	`$GIT_URL/info/refs?service=git-upload-pack` requests. See
+	"Smart Clients" in link:technical/http-protocol.html[the HTTP
+	transfer protocols] documentation and "HTTP Transport" in
+	link:technical/protocol-v2.html[the Git Wire Protocol, Version
+	2] documentation. Also understood by
+	linkgit:git-receive-pack[1].
 
 <directory>::
 	The repository to sync from.
diff --git a/Documentation/technical/http-protocol.txt b/Documentation/technical/http-protocol.txt
index 96d89ea9b2..cc5126cfed 100644
--- a/Documentation/technical/http-protocol.txt
+++ b/Documentation/technical/http-protocol.txt
@@ -225,6 +225,9 @@ The client may send Extra Parameters (see
 Documentation/technical/pack-protocol.txt) as a colon-separated string
 in the Git-Protocol HTTP header.
 
+Uses the `--http-backend-info-refs` option to
+linkgit:git-upload-pack[1].
+
 Dumb Server Response
 ^^^^^^^^^^^^^^^^^^^^
 Dumb servers MUST respond with the dumb server reply format.
diff --git a/Documentation/technical/protocol-v2.txt b/Documentation/technical/protocol-v2.txt
index 1040d85319..213538f1d0 100644
--- a/Documentation/technical/protocol-v2.txt
+++ b/Documentation/technical/protocol-v2.txt
@@ -81,6 +81,9 @@ A v2 server would reply:
 Subsequent requests are then made directly to the service
 `$GIT_URL/git-upload-pack`. (This works the same for git-receive-pack).
 
+Uses the `--http-backend-info-refs` option to
+linkgit:git-upload-pack[1].
+
 Capability Advertisement
 ------------------------
 
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 2d1f97e1ca..7ffb45d706 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -2477,7 +2477,8 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 	struct option options[] = {
 		OPT__QUIET(&quiet, N_("quiet")),
 		OPT_HIDDEN_BOOL(0, "stateless-rpc", &stateless_rpc, NULL),
-		OPT_HIDDEN_BOOL(0, "advertise-refs", &advertise_refs, NULL),
+		OPT_HIDDEN_BOOL(0, "http-backend-info-refs", &advertise_refs, NULL),
+		OPT_ALIAS(0, "advertise-refs", "http-backend-info-refs"),
 		OPT_HIDDEN_BOOL(0, "reject-thin-pack-for-testing", &reject_thin, NULL),
 		OPT_END()
 	};
diff --git a/builtin/upload-pack.c b/builtin/upload-pack.c
index 8506030a64..125af53885 100644
--- a/builtin/upload-pack.c
+++ b/builtin/upload-pack.c
@@ -22,8 +22,9 @@ int cmd_upload_pack(int argc, const char **argv, const char *prefix)
 	struct option options[] = {
 		OPT_BOOL(0, "stateless-rpc", &stateless_rpc,
 			 N_("quit after a single request/response exchange")),
-		OPT_BOOL(0, "advertise-refs", &advertise_refs,
-			 N_("exit immediately after initial ref advertisement")),
+		OPT_HIDDEN_BOOL(0, "http-backend-info-refs", &advertise_refs,
+				N_("serve up the info/refs for git-http-backend")),
+		OPT_ALIAS(0, "advertise-refs", "http-backend-info-refs"),
 		OPT_BOOL(0, "strict", &strict,
 			 N_("do not try <directory>/.git/ if <directory> is no Git directory")),
 		OPT_INTEGER(0, "timeout", &timeout,
diff --git a/http-backend.c b/http-backend.c
index d37463cec8..838374edb9 100644
--- a/http-backend.c
+++ b/http-backend.c
@@ -534,7 +534,7 @@ static void get_info_refs(struct strbuf *hdr, char *arg)
 
 	if (service_name) {
 		const char *argv[] = {NULL /* service name */,
-			"--advertise-refs",
+			"--http-backend-info-refs",
 			".", NULL};
 		struct rpc_service *svc = select_service(hdr, service_name);
 
diff --git a/t/t5555-http-smart-common.sh b/t/t5555-http-smart-common.sh
index b813099ed2..49faf5e283 100755
--- a/t/t5555-http-smart-common.sh
+++ b/t/t5555-http-smart-common.sh
@@ -8,6 +8,20 @@ test_expect_success 'setup' '
 	test_commit --no-tag initial
 '
 
+test_expect_success 'git upload-pack --http-backend-info-refs and --advertise-refs are aliased' '
+	git upload-pack --http-backend-info-refs . >expected 2>err.expected &&
+	git upload-pack --advertise-refs . >actual 2>err.actual &&
+	test_cmp err.expected err.actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'git receive-pack --http-backend-info-refs and --advertise-refs are aliased' '
+	git receive-pack --http-backend-info-refs . >expected 2>err.expected &&
+	git receive-pack --advertise-refs . >actual 2>err.actual &&
+	test_cmp err.expected err.actual &&
+	test_cmp expected actual
+'
+
 test_expect_success 'git upload-pack --advertise-refs' '
 	cat >expect <<-EOF &&
 	$(git rev-parse HEAD) HEAD