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-include and --negotiation-restrict options from the
'remote.<name>.negotiationInclude' 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 negotiationInclude is configured, the specified ref patterns
are passed as --negotiation-include to ensure their tips are always
sent as 'have' lines during push negotiation.

Reviewed-by: Matthew John Cheetham <mjcheetham@outlook.com>
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/config/remote.adoc

@@ -122,6 +122,9 @@ command-line option.  If `--negotiation-restrict` (or its synonym
 `--negotiation-tip`) is specified on the command line, then the config
 values are not used.
 +
+These values also influence negotiation during `git push` if
+`push.negotiate` is enabled.
++
 Blank values signal to ignore all previous values, allowing a reset of
 the list from broader config scenarios.
 
@@ -147,6 +150,9 @@ negotiation algorithm still runs and advertises its own selected commits,
 but the refs matching `remote.<name>.negotiationInclude` are sent
 unconditionally on top of those heuristically selected commits.
 +
+These values also influence negotiation during `git push` if
+`push.negotiate` is enabled.
++
 Blank values signal to ignore all previous values, allowing a reset of
 the list from broader config scenarios.
 

send-pack.c

@@ -433,28 +433,48 @@ 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_include,
+					    const struct string_list *negotiation_restrict,
 					    const struct ref *remote_refs,
 					    struct oid_array *commons)
 {
 	struct child_process child = CHILD_PROCESS_INIT;
 	const struct ref *ref;
 	int len = r->hash_algo->hexsz + 1; /* hash + NL */
-	int nr_negotiation_tip = 0;
+	int nr_negotiation = 0;
 
 	child.git_cmd = 1;
 	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)) {
+
+	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",
-				     oid_to_hex(&ref->new_oid));
-			nr_negotiation_tip++;
+				     item->string);
+		nr_negotiation = negotiation_restrict->nr;
+	} else {
+		for (ref = remote_refs; ref; ref = ref->next) {
+			if (!is_null_oid(&ref->new_oid)) {
+				strvec_pushf(&child.args, "--negotiation-restrict=%s",
+					     oid_to_hex(&ref->new_oid));
+				nr_negotiation++;
+			}
 		}
 	}
+
+	if (negotiation_include && negotiation_include->nr) {
+		struct string_list_item *item;
+		for_each_string_list_item(item, negotiation_include)
+			strvec_pushf(&child.args, "--negotiation-include=%s",
+				     item->string);
+		nr_negotiation += negotiation_include->nr;
+	}
+
 	strvec_push(&child.args, url);
 
-	if (!nr_negotiation_tip) {
+	if (!nr_negotiation) {
 		child_process_clear(&child);
 		return;
 	}
@@ -528,7 +548,10 @@ 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_include,
+					       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_include;
+	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>.negotiationInclude' '
+	test_when_finished rm -rf negotiation_include &&
+	mk_empty negotiation_include &&
+	git push negotiation_include $the_first_commit:refs/remotes/origin/first_commit &&
+	test_commit -C negotiation_include unrelated_commit &&
+	git -C negotiation_include config receive.hideRefs refs/remotes/origin/first_commit &&
+	test_when_finished "rm event" &&
+	GIT_TRACE2_EVENT="$(pwd)/event" \
+		git -c protocol.version=2 -c push.negotiate=1 \
+		-c remote.negotiation_include.negotiationInclude=refs/heads/main \
+		push negotiation_include 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_include = &transport->remote->negotiation_include;
+	args.negotiation_restrict = &transport->remote->negotiation_restrict;
 
 	if (flags & TRANSPORT_PUSH_CERT_ALWAYS)
 		args.push_cert = SEND_PACK_PUSH_CERT_ALWAYS;