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fix(spigot): support Mojang-mapped NMS classes (Paper 1.20.5+ / Spigot 1.20.5+) #23

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Merged
robinbraemer merged 1 commit into from
May 1, 2026
Merged

fix(spigot): support Mojang-mapped NMS classes (Paper 1.20.5+ / Spigot 1.20.5+) #23

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150 changes: 113 additions & 37 deletions spigot/src/main/java/com/minekube/connect/util/ClassNames.java
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Original file line number Diff line number Diff line change
Expand Up @@ -120,10 +120,21 @@ public class ClassNames {
nmsPackage + "MinecraftServer"
);

SERVER_CONNECTION = getClassOrFallback(
"net.minecraft.server.network.ServerConnection",
nmsPackage + "ServerConnection"
);
// Paper 1.20.5+ uses Mojang mappings: ServerConnection -> ServerConnectionListener
Class<?> serverConnectionClass = getClassSilently(
"net.minecraft.server.network.ServerConnectionListener");
if (serverConnectionClass == null) {
serverConnectionClass = getClassSilently(
"net.minecraft.server.network.ServerConnection");
}
if (serverConnectionClass == null) {
serverConnectionClass = getClassSilently(nmsPackage + "ServerConnection");
}
if (serverConnectionClass == null) {
throw new IllegalStateException(
"Could not find ServerConnection/ServerConnectionListener class.");
}
SERVER_CONNECTION = serverConnectionClass;

// WhitelistUtils
Class<?> craftServerClass = ReflectionUtils.getClass(
Expand All @@ -135,30 +146,66 @@ public class ClassNames {
craftOfflinePlayerClass, true, craftServerClass, GameProfile.class);

// SpigotDataHandler
Class<?> networkManager = getClassOrFallback(
"net.minecraft.network.NetworkManager",
nmsPackage + "NetworkManager"
);
// Paper 1.20.5+ uses Mojang mappings: NetworkManager -> Connection
Class<?> networkManager = getClassSilently("net.minecraft.network.Connection");
if (networkManager == null) {
networkManager = getClassSilently("net.minecraft.network.NetworkManager");
}
if (networkManager == null) {
networkManager = getClassSilently(nmsPackage + "NetworkManager");
}
if (networkManager == null) {
throw new IllegalStateException("Could not find NetworkManager/Connection class.");
}

SOCKET_ADDRESS = getFieldOfType(networkManager, SocketAddress.class, false);

HANDSHAKE_PACKET = getClassOrFallback(
"net.minecraft.network.protocol.handshake.PacketHandshakingInSetProtocol",
nmsPackage + "PacketHandshakingInSetProtocol"
);
// Paper 1.20.5+ uses Mojang mappings: PacketHandshakingInSetProtocol -> ClientIntentionPacket
Class<?> handshakePacket = getClassSilently(
"net.minecraft.network.protocol.handshake.ClientIntentionPacket");
if (handshakePacket == null) {
handshakePacket = getClassSilently(
"net.minecraft.network.protocol.handshake.PacketHandshakingInSetProtocol");
}
if (handshakePacket == null) {
handshakePacket = getClassSilently(nmsPackage + "PacketHandshakingInSetProtocol");
}
if (handshakePacket == null) {
throw new IllegalStateException("Could not find HandshakePacket class.");
}
HANDSHAKE_PACKET = handshakePacket;

HANDSHAKE_HOST = getFieldOfType(HANDSHAKE_PACKET, String.class);
checkNotNull(HANDSHAKE_HOST, "Handshake host");

LOGIN_START_PACKET = getClassOrFallback(
"net.minecraft.network.protocol.login.PacketLoginInStart",
nmsPackage + "PacketLoginInStart"
);
// Paper 1.20.5+ uses Mojang mappings: PacketLoginInStart -> ServerboundHelloPacket
Class<?> loginStartPacket = getClassSilently(
"net.minecraft.network.protocol.login.ServerboundHelloPacket");
if (loginStartPacket == null) {
loginStartPacket = getClassSilently(
"net.minecraft.network.protocol.login.PacketLoginInStart");
}
if (loginStartPacket == null) {
loginStartPacket = getClassSilently(nmsPackage + "PacketLoginInStart");
}
if (loginStartPacket == null) {
throw new IllegalStateException("Could not find LoginStartPacket class.");
}
LOGIN_START_PACKET = loginStartPacket;

LOGIN_LISTENER = getClassOrFallback(
"net.minecraft.server.network.LoginListener",
nmsPackage + "LoginListener"
);
// Paper 1.20.5+ uses Mojang mappings: LoginListener -> ServerLoginPacketListenerImpl
Class<?> loginListener = getClassSilently(
"net.minecraft.server.network.ServerLoginPacketListenerImpl");
if (loginListener == null) {
loginListener = getClassSilently("net.minecraft.server.network.LoginListener");
}
if (loginListener == null) {
loginListener = getClassSilently(nmsPackage + "LoginListener");
}
if (loginListener == null) {
throw new IllegalStateException("Could not find LoginListener class.");
}
LOGIN_LISTENER = loginListener;

LOGIN_PROFILE = getFieldOfType(LOGIN_LISTENER, GameProfile.class);
checkNotNull(LOGIN_PROFILE, "Profile from LoginListener");
Expand Down Expand Up @@ -189,10 +236,12 @@ public class ClassNames {


if (IS_PRE_1_20_2) {
Class<?> packetListenerClass = getClassOrFallback(
"net.minecraft.network.PacketListener",
nmsPackage + "PacketListener"
);
Class<?> packetListenerClass = getClassSilently(
"net.minecraft.network.PacketListener");
if (packetListenerClass == null) {
packetListenerClass = ReflectionUtils.getClassOrThrow(
nmsPackage + "PacketListener");
}

PACKET_LISTENER = getFieldOfType(networkManager, packetListenerClass);
} else {
Expand Down Expand Up @@ -225,10 +274,17 @@ public class ClassNames {
FIRE_LOGIN_EVENTS = null;
FIRE_LOGIN_EVENTS_GAME_PROFILE = null;
} else {
Class<?> loginHandler = getClassOrFallback(
"net.minecraft.server.network.LoginListener$LoginHandler",
nmsPackage + "LoginListener$LoginHandler"
);
// Paper 1.20.5+ uses Mojang mappings: LoginListener$LoginHandler -> ServerLoginPacketListenerImpl$LoginHandler
Class<?> loginHandler = getClassSilently(
"net.minecraft.server.network.ServerLoginPacketListenerImpl$LoginHandler");
if (loginHandler == null) {
loginHandler = getClassSilently(
"net.minecraft.server.network.LoginListener$LoginHandler");
}
if (loginHandler == null) {
loginHandler = ReflectionUtils.getClassOrThrow(
nmsPackage + "LoginListener$LoginHandler");
}
LOGIN_HANDLER_CONSTRUCTOR =
getConstructor(loginHandler, true, LOGIN_LISTENER);
checkNotNull(LOGIN_HANDLER_CONSTRUCTOR, "LoginHandler constructor");
Expand Down Expand Up @@ -313,15 +369,30 @@ public class ClassNames {
String.class, int.class, CLIENT_INTENT);
checkNotNull(HANDSHAKE_PACKET_CONSTRUCTOR, "Handshake packet constructor");

Field a = getField(HANDSHAKE_PACKET, "a");
checkNotNull(a,"Handshake \"a\" field (protocol version, or stream codec)");

if (a.getType().isPrimitive()) { // 1.20.2 - 1.20.4: a is the protocol version (int)
HANDSHAKE_PROTOCOL = a;
HANDSHAKE_PORT = getField(HANDSHAKE_PACKET, "c");
} else { // 1.20.5: a is the stream_codec thing, so everything is shifted
// Paper 1.20.5+ Mojang mappings expose real field names; older Spigot uses obfuscated a/b/c/d.
// Try Mojang name first, then obfuscated.
Field protocolField = getField(HANDSHAKE_PACKET, "protocolVersion");
if (protocolField == null) {
protocolField = getField(HANDSHAKE_PACKET, "a");
}
checkNotNull(protocolField, "Handshake \"a\" field (protocol version, or stream codec)");

if (protocolField.getType().isPrimitive()) {
// Mojang on 1.20.5+ OR obfuscated 1.20.2-1.20.4: int field is the protocol version
HANDSHAKE_PROTOCOL = protocolField;
Field portField = getField(HANDSHAKE_PACKET, "port");
if (portField == null) {
portField = getField(HANDSHAKE_PACKET, "c");
}
HANDSHAKE_PORT = portField;
} else {
// Obfuscated 1.20.5: a is the stream_codec, everything is shifted
HANDSHAKE_PROTOCOL = getField(HANDSHAKE_PACKET, "b");
HANDSHAKE_PORT = getField(HANDSHAKE_PACKET, "d");
Field portField = getField(HANDSHAKE_PACKET, "port");
if (portField == null) {
portField = getField(HANDSHAKE_PACKET, "d");
}
HANDSHAKE_PORT = portField;
}

checkNotNull(HANDSHAKE_PROTOCOL, "Handshake protocol");
Expand All @@ -330,7 +401,12 @@ public class ClassNames {
checkNotNull(HANDSHAKE_PORT, "Handshake port");
makeAccessible(HANDSHAKE_PORT);

HANDSHAKE_INTENTION = getFieldOfType(HANDSHAKE_PACKET, CLIENT_INTENT);
// Try Mojang field name first, then fall back to type-based lookup (obfuscated)
Field intentionField = getField(HANDSHAKE_PACKET, "intention");
if (intentionField == null) {
intentionField = getFieldOfType(HANDSHAKE_PACKET, CLIENT_INTENT);
}
HANDSHAKE_INTENTION = intentionField;
checkNotNull(HANDSHAKE_INTENTION, "Handshake intention");
makeAccessible(HANDSHAKE_INTENTION);
} else {
Expand Down
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