send-pack: pass negotiation config in push

When push.negotiate is enabled, 'git push' spawns a child 'git fetch
--negotiate-only' process to find common commits.  Pass
--negotiation-require and --negotiation-restrict options from the
'remote.<name>.negotiationRequire' and
'remote.<name>.negotiationRestrict' config keys to this child process.

When negotiationRestrict is configured, it replaces the default
behavior of using all remote refs as negotiation tips. This allows
the user to control which local refs are used for push negotiation.

When negotiationRequire is configured, the specified ref patterns
are passed as --negotiation-require to ensure their tips are always
sent as 'have' lines during push negotiation.

This change also updates the use of --negotiation-tip into
--negotiation-restrict now that the new synonym exists.

Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: derrickstolee

send-pack.c

@@ -433,6 +433,8 @@ static void reject_invalid_nonce(const char *nonce, int len)
 
 static void get_commons_through_negotiation(struct repository *r,
 					    const char *url,
+					    const struct string_list *negotiation_require,
+					    const struct string_list *negotiation_restrict,
 					    const struct ref *remote_refs,
 					    struct oid_array *commons)
 {
@@ -445,13 +447,30 @@ static void get_commons_through_negotiation(struct repository *r,
 	child.no_stdin = 1;
 	child.out = -1;
 	strvec_pushl(&child.args, "fetch", "--negotiate-only", NULL);
-	for (ref = remote_refs; ref; ref = ref->next) {
-		if (!is_null_oid(&ref->new_oid)) {
-			strvec_pushf(&child.args, "--negotiation-tip=%s",
-				     oid_to_hex(&ref->new_oid));
-			nr_negotiation_tip++;
+
+	if (negotiation_restrict && negotiation_restrict->nr) {
+		struct string_list_item *item;
+		for_each_string_list_item(item, negotiation_restrict)
+			strvec_pushf(&child.args, "--negotiation-restrict=%s",
+				     item->string);
+		nr_negotiation_tip = negotiation_restrict->nr;
+	} else {
+		for (ref = remote_refs; ref; ref = ref->next) {
+			if (!is_null_oid(&ref->new_oid)) {
+				strvec_pushf(&child.args, "--negotiation-tip=%s",
+					     oid_to_hex(&ref->new_oid));
+				nr_negotiation_tip++;
+			}
 		}
 	}
+
+	if (negotiation_require && negotiation_require->nr) {
+		struct string_list_item *item;
+		for_each_string_list_item(item, negotiation_require)
+			strvec_pushf(&child.args, "--negotiation-require=%s",
+				     item->string);
+	}
+
 	strvec_push(&child.args, url);
 
 	if (!nr_negotiation_tip) {
@@ -528,7 +547,10 @@ int send_pack(struct repository *r,
 	repo_config_get_bool(r, "push.negotiate", &push_negotiate);
 	if (push_negotiate) {
 		trace2_region_enter("send_pack", "push_negotiate", r);
-		get_commons_through_negotiation(r, args->url, remote_refs, &commons);
+		get_commons_through_negotiation(r, args->url,
+					       args->negotiation_require,
+					       args->negotiation_restrict,
+					       remote_refs, &commons);
 		trace2_region_leave("send_pack", "push_negotiate", r);
 	}
 

send-pack.h

@@ -18,6 +18,8 @@ struct repository;
 
 struct send_pack_args {
 	const char *url;
+	const struct string_list *negotiation_require;
+	const struct string_list *negotiation_restrict;
 	unsigned verbose:1,
 		quiet:1,
 		porcelain:1,

t/t5516-fetch-push.sh

@@ -254,6 +254,36 @@ test_expect_success 'push with negotiation does not attempt to fetch submodules'
 	! grep "Fetching submodule" err
 '
 
+test_expect_success 'push with negotiation and remote.<name>.negotiationRequire' '
+	test_when_finished rm -rf negotiation_require &&
+	mk_empty negotiation_require &&
+	git push negotiation_require $the_first_commit:refs/remotes/origin/first_commit &&
+	test_commit -C negotiation_require unrelated_commit &&
+	git -C negotiation_require config receive.hideRefs refs/remotes/origin/first_commit &&
+	test_when_finished "rm event" &&
+	GIT_TRACE2_EVENT="$(pwd)/event" \
+		git -c protocol.version=2 -c push.negotiate=1 \
+		-c remote.negotiation_require.negotiationRequire=refs/heads/main \
+		push negotiation_require refs/heads/main:refs/remotes/origin/main &&
+	test_grep \"key\":\"total_rounds\" event &&
+	grep_wrote 2 event # 1 commit, 1 tree
+'
+
+test_expect_success 'push with negotiation and remote.<name>.negotiationRestrict' '
+	test_when_finished rm -rf negotiation_restrict &&
+	mk_empty negotiation_restrict &&
+	git push negotiation_restrict $the_first_commit:refs/remotes/origin/first_commit &&
+	test_commit -C negotiation_restrict unrelated_commit &&
+	git -C negotiation_restrict config receive.hideRefs refs/remotes/origin/first_commit &&
+	test_when_finished "rm event" &&
+	GIT_TRACE2_EVENT="$(pwd)/event" \
+		git -c protocol.version=2 -c push.negotiate=1 \
+		-c remote.negotiation_restrict.negotiationRestrict=refs/heads/main \
+		push negotiation_restrict refs/heads/main:refs/remotes/origin/main &&
+	test_grep \"key\":\"total_rounds\" event &&
+	grep_wrote 2 event # 1 commit, 1 tree
+'
+
 test_expect_success 'push without wildcard' '
 	mk_empty testrepo &&
 

transport.c

@@ -921,6 +921,8 @@ static int git_transport_push(struct transport *transport, struct ref *remote_re
 	args.atomic = !!(flags & TRANSPORT_PUSH_ATOMIC);
 	args.push_options = transport->push_options;
 	args.url = transport->url;
+	args.negotiation_require = &transport->remote->negotiation_require;
+	args.negotiation_restrict = &transport->remote->negotiation_restrict;
 
 	if (flags & TRANSPORT_PUSH_CERT_ALWAYS)
 		args.push_cert = SEND_PACK_PUSH_CERT_ALWAYS;