fix: use MultiUserServerConfig for SS2022 with empty clients array

infra/conf/shadowsocks.go

@@ -99,7 +99,7 @@ func (v *ShadowsocksServerConfig) Build() (proto.Message, error) {
 }
 
 func buildShadowsocks2022(v *ShadowsocksServerConfig) (proto.Message, error) {
-	if len(v.Users) == 0 {
+	if v.Users == nil {
 		config := new(shadowsocks_2022.ServerConfig)
 		config.Method = v.Cipher
 		config.Key = v.Password
@@ -115,7 +115,7 @@ func buildShadowsocks2022(v *ShadowsocksServerConfig) (proto.Message, error) {
 		return nil, errors.New("shadowsocks 2022 (multi-user): only blake3-aes-*-gcm methods are supported")
 	}
 
-	if v.Users[0].Address == nil {
+	if len(v.Users) == 0 || v.Users[0].Address == nil {
 		config := new(shadowsocks_2022.MultiUserServerConfig)
 		config.Method = v.Cipher
 		config.Key = v.Password

infra/conf/shadowsocks_test.go

@@ -8,6 +8,7 @@ import (
 	"github.com/xtls/xray-core/common/serial"
 	. "github.com/xtls/xray-core/infra/conf"
 	"github.com/xtls/xray-core/proxy/shadowsocks"
+	"github.com/xtls/xray-core/proxy/shadowsocks_2022"
 )
 
 func TestShadowsocksServerConfigParsing(t *testing.T) {
@@ -34,3 +35,39 @@ func TestShadowsocksServerConfigParsing(t *testing.T) {
 		},
 	})
 }
+
+func TestShadowsocks2022ServerConfigParsing(t *testing.T) {
+	creator := func() Buildable {
+		return new(ShadowsocksServerConfig)
+	}
+
+	runMultiTestCase(t, []TestCase{
+		{
+			// No clients field: should produce single-user ServerConfig
+			Input: `{
+				"method": "2022-blake3-aes-128-gcm",
+				"password": "aGVsbG93b3JsZDEyMzQ1Ng=="
+			}`,
+			Parser: loadJSON(creator),
+			Output: &shadowsocks_2022.ServerConfig{
+				Method:  "2022-blake3-aes-128-gcm",
+				Key:     "aGVsbG93b3JsZDEyMzQ1Ng==",
+				Network: []net.Network{net.Network_TCP},
+			},
+		},
+		{
+			// Empty clients array: should produce multi-user MultiUserServerConfig
+			Input: `{
+				"method": "2022-blake3-aes-128-gcm",
+				"password": "aGVsbG93b3JsZDEyMzQ1Ng==",
+				"clients": []
+			}`,
+			Parser: loadJSON(creator),
+			Output: &shadowsocks_2022.MultiUserServerConfig{
+				Method:  "2022-blake3-aes-128-gcm",
+				Key:     "aGVsbG93b3JsZDEyMzQ1Ng==",
+				Network: []net.Network{net.Network_TCP},
+			},
+		},
+	})
+}