Fix networking v1 (#1205)

* Handle registration of global handlers as early as possible.

This may not be correct?

* Do not handle packets on game thread

* Add PLAY_READY event

* READY -> JOIN, some javadoc clarifications and impl oversight fixes

* Omit redundant PLAY and LOGIN prefixes in events

* Checkstyle go brr

fabric-networking-api-v1/src/main/java/net/fabricmc/fabric/api/client/networking/v1/ClientLoginConnectionEvents.java

@@ -18,6 +18,7 @@ package net.fabricmc.fabric.api.client.networking.v1;
 
 import net.minecraft.client.MinecraftClient;
 import net.minecraft.client.network.ClientLoginNetworkHandler;
+import net.minecraft.util.Identifier;
 
 import net.fabricmc.api.EnvType;
 import net.fabricmc.api.Environment;
@@ -30,14 +31,14 @@ import net.fabricmc.fabric.api.event.EventFactory;
 @Environment(EnvType.CLIENT)
 public final class ClientLoginConnectionEvents {
 	/**
-	 * An event for when the client's login process has begun.
+	 * Event indicating a connection entered the LOGIN state, ready for registering query request handlers.
 	 * This event may be used by mods to prepare their client side state.
 	 * This event does not guarantee that a login attempt will be successful.
 	 *
-	 * <p>No packets should be sent when this event is invoked.
+	 * @see ClientLoginNetworking#registerReceiver(Identifier, ClientLoginNetworking.LoginQueryRequestHandler)
 	 */
-	public static final Event<LoginInit> LOGIN_INIT = EventFactory.createArrayBacked(LoginInit.class, callbacks -> (handler, client) -> {
-		for (LoginInit callback : callbacks) {
+	public static final Event<Init> INIT = EventFactory.createArrayBacked(Init.class, callbacks -> (handler, client) -> {
+		for (Init callback : callbacks) {
 			callback.onLoginStart(handler, client);
 		}
 	});
@@ -56,8 +57,8 @@ public final class ClientLoginConnectionEvents {
 	 *
 	 * <p>No packets should be sent when this event is invoked.
 	 */
-	public static final Event<LoginQueryStart> LOGIN_QUERY_START = EventFactory.createArrayBacked(LoginQueryStart.class, callbacks -> (handler, client) -> {
-		for (LoginQueryStart callback : callbacks) {
+	public static final Event<QueryStart> QUERY_START = EventFactory.createArrayBacked(QueryStart.class, callbacks -> (handler, client) -> {
+		for (QueryStart callback : callbacks) {
 			callback.onLoginQueryStart(handler, client);
 		}
 	});
@@ -67,8 +68,8 @@ public final class ClientLoginConnectionEvents {
 	 *
 	 * <p>No packets should be sent when this event is invoked.
 	 */
-	public static final Event<LoginDisconnect> LOGIN_DISCONNECT = EventFactory.createArrayBacked(LoginDisconnect.class, callbacks -> (handler, client) -> {
-		for (LoginDisconnect callback : callbacks) {
+	public static final Event<Disconnect> DISCONNECT = EventFactory.createArrayBacked(Disconnect.class, callbacks -> (handler, client) -> {
+		for (Disconnect callback : callbacks) {
 			callback.onLoginDisconnect(handler, client);
 		}
 	});
@@ -77,29 +78,29 @@ public final class ClientLoginConnectionEvents {
 	}
 
 	/**
-	 * @see ClientLoginConnectionEvents#LOGIN_INIT
+	 * @see ClientLoginConnectionEvents#INIT
 	 */
 	@Environment(EnvType.CLIENT)
 	@FunctionalInterface
-	public interface LoginInit {
+	public interface Init {
 		void onLoginStart(ClientLoginNetworkHandler handler, MinecraftClient client);
 	}
 
 	/**
-	 * @see ClientLoginConnectionEvents#LOGIN_QUERY_START
+	 * @see ClientLoginConnectionEvents#QUERY_START
 	 */
 	@Environment(EnvType.CLIENT)
 	@FunctionalInterface
-	public interface LoginQueryStart {
+	public interface QueryStart {
 		void onLoginQueryStart(ClientLoginNetworkHandler handler, MinecraftClient client);
 	}
 
 	/**
-	 * @see ClientLoginConnectionEvents#LOGIN_DISCONNECT
+	 * @see ClientLoginConnectionEvents#DISCONNECT
 	 */
 	@Environment(EnvType.CLIENT)
 	@FunctionalInterface
-	public interface LoginDisconnect {
+	public interface Disconnect {
 		void onLoginDisconnect(ClientLoginNetworkHandler handler, MinecraftClient client);
 	}
 }

fabric-networking-api-v1/src/main/java/net/fabricmc/fabric/api/client/networking/v1/ClientLoginNetworking.java

@@ -51,7 +51,7 @@ public final class ClientLoginNetworking {
 	 * A global receiver is registered to all connections, in the present and future.
 	 *
 	 * <p>If a handler is already registered to the {@code channel}, this method will return {@code false}, and no change will be made.
-	 * Use {@link #unregisterGlobalReceiver(Identifier)} to unregister the existing handler.</p>
+	 * Use {@link #unregisterGlobalReceiver(Identifier)} to unregister the existing handler.
 	 *
 	 * @param channelName the id of the channel
 	 * @param queryHandler the handler
@@ -67,7 +67,7 @@ public final class ClientLoginNetworking {
 	 * Removes the handler of a query request channel.
 	 * A global receiver is registered to all connections, in the present and future.
 	 *
-	 * <p>The {@code channel} is guaranteed not to have a handler after this call.</p>
+	 * <p>The {@code channel} is guaranteed not to have a handler after this call.
 	 *
 	 * @param channelName the id of the channel
 	 * @return the previous handler, or {@code null} if no handler was bound to the channel
@@ -93,7 +93,7 @@ public final class ClientLoginNetworking {
 	 * Registers a handler to a query request channel.
 	 *
 	 * <p>If a handler is already registered to the {@code channelName}, this method will return {@code false}, and no change will be made.
-	 * Use {@link #unregisterReceiver(Identifier)} to unregister the existing handler.</p>
+	 * Use {@link #unregisterReceiver(Identifier)} to unregister the existing handler.
 	 *
 	 * @param channelName the id of the channel
 	 * @param queryHandler the handler
@@ -117,7 +117,7 @@ public final class ClientLoginNetworking {
 	/**
 	 * Removes the handler of a query request channel.
 	 *
-	 * <p>The {@code channelName} is guaranteed not to have a handler after this call.</p>
+	 * <p>The {@code channelName} is guaranteed not to have a handler after this call.
 	 *
 	 * @param channelName the id of the channel
 	 * @return the previous handler, or {@code null} if no handler was bound to the channel name

fabric-networking-api-v1/src/main/java/net/fabricmc/fabric/api/client/networking/v1/ClientPlayConnectionEvents.java

@@ -18,6 +18,7 @@ package net.fabricmc.fabric.api.client.networking.v1;
 
 import net.minecraft.client.MinecraftClient;
 import net.minecraft.client.network.ClientPlayNetworkHandler;
+import net.minecraft.util.Identifier;
 
 import net.fabricmc.api.EnvType;
 import net.fabricmc.api.Environment;
@@ -31,13 +32,25 @@ import net.fabricmc.fabric.api.networking.v1.PacketSender;
 @Environment(EnvType.CLIENT)
 public final class ClientPlayConnectionEvents {
 	/**
-	 * An event for the initialization of the client play network handler.
+	 * Event indicating a connection entered the PLAY state, ready for registering channel handlers.
+	 *
+	 * @see ClientPlayNetworking#registerReceiver(Identifier, ClientPlayNetworking.PlayChannelHandler)
+	 */
+	public static final Event<Init> INIT = EventFactory.createArrayBacked(Init.class, callbacks -> (handler, client) -> {
+		for (Init callback : callbacks) {
+			callback.onPlayInit(handler, client);
+		}
+	});
+
+	/**
+	 * An event for notification when the client play network handler is ready to send packets to the server.
 	 *
 	 * <p>At this stage, the network handler is ready to send packets to the server.
+	 * Since the client's local state has been setup.
 	 */
-	public static final Event<PlayInit> PLAY_INIT = EventFactory.createArrayBacked(PlayInit.class, callbacks -> (handler, sender, client) -> {
-		for (PlayInit callback : callbacks) {
-			callback.onPlayInit(handler, sender, client);
+	public static final Event<Join> JOIN = EventFactory.createArrayBacked(Join.class, callbacks -> (handler, sender, client) -> {
+		for (Join callback : callbacks) {
+			callback.onPlayReady(handler, sender, client);
 		}
 	});
 
@@ -46,8 +59,8 @@ public final class ClientPlayConnectionEvents {
 	 *
 	 * <p>No packets should be sent when this event is invoked.
 	 */
-	public static final Event<PlayDisconnect> PLAY_DISCONNECT = EventFactory.createArrayBacked(PlayDisconnect.class, callbacks -> (handler, client) -> {
-		for (PlayDisconnect callback : callbacks) {
+	public static final Event<Disconnect> DISCONNECT = EventFactory.createArrayBacked(Disconnect.class, callbacks -> (handler, client) -> {
+		for (Disconnect callback : callbacks) {
 			callback.onPlayDisconnect(handler, client);
 		}
 	});
@@ -57,13 +70,19 @@ public final class ClientPlayConnectionEvents {
 
 	@Environment(EnvType.CLIENT)
 	@FunctionalInterface
-	public interface PlayInit {
-		void onPlayInit(ClientPlayNetworkHandler handler, PacketSender sender, MinecraftClient client);
+	public interface Init {
+		void onPlayInit(ClientPlayNetworkHandler handler, MinecraftClient client);
 	}
 
 	@Environment(EnvType.CLIENT)
 	@FunctionalInterface
-	public interface PlayDisconnect {
+	public interface Join {
+		void onPlayReady(ClientPlayNetworkHandler handler, PacketSender sender, MinecraftClient client);
+	}
+
+	@Environment(EnvType.CLIENT)
+	@FunctionalInterface
+	public interface Disconnect {
 		void onPlayDisconnect(ClientPlayNetworkHandler handler, MinecraftClient client);
 	}
 }

fabric-networking-api-v1/src/main/java/net/fabricmc/fabric/api/client/networking/v1/ClientPlayNetworking.java

@@ -51,7 +51,7 @@ public final class ClientPlayNetworking {
 	 * A global receiver is registered to all connections, in the present and future.
 	 *
 	 * <p>If a handler is already registered to the {@code channel}, this method will return {@code false}, and no change will be made.
-	 * Use {@link #unregisterGlobalReceiver(Identifier)} to unregister the existing handler.</p>
+	 * Use {@link #unregisterGlobalReceiver(Identifier)} to unregister the existing handler.
 	 *
 	 * @param channelName the id of the channel
 	 * @param channelHandler the handler
@@ -67,7 +67,7 @@ public final class ClientPlayNetworking {
 	 * Removes the handler of a channel.
 	 * A global receiver is registered to all connections, in the present and future.
 	 *
-	 * <p>The {@code channel} is guaranteed not to have a handler after this call.</p>
+	 * <p>The {@code channel} is guaranteed not to have a handler after this call.
 	 *
 	 * @param channelName the id of the channel
 	 * @return the previous handler, or {@code null} if no handler was bound to the channel
@@ -93,11 +93,15 @@ public final class ClientPlayNetworking {
 	 * Registers a handler to a channel.
 	 *
 	 * <p>If a handler is already registered to the {@code channel}, this method will return {@code false}, and no change will be made.
-	 * Use {@link #unregisterReceiver(Identifier)} to unregister the existing handler.</p>
+	 * Use {@link #unregisterReceiver(Identifier)} to unregister the existing handler.
+	 *
+	 * <p>For example, if you only register a receiver using this method when a {@linkplain ClientLoginNetworking#registerGlobalReceiver(Identifier, ClientLoginNetworking.LoginQueryRequestHandler)}
+	 * login query has been received, you should use {@link ClientPlayConnectionEvents#INIT} to register the channel handler.
 	 *
 	 * @param channelName the id of the channel
 	 * @return false if a handler is already registered to the channel
 	 * @throws IllegalStateException if the client is not connected to a server
+	 * @see ClientPlayConnectionEvents#INIT
 	 */
 	public static boolean registerReceiver(Identifier channelName, PlayChannelHandler channelHandler) {
 		if (MinecraftClient.getInstance().getNetworkHandler() != null) {
@@ -110,7 +114,7 @@ public final class ClientPlayNetworking {
 	/**
 	 * Removes the handler of a channel.
 	 *
-	 * <p>The {@code channel} is guaranteed not to have a handler after this call.</p>
+	 * <p>The {@code channelName} is guaranteed not to have a handler after this call.
 	 *
 	 * @param channelName the id of the channel
 	 * @return the previous handler, or {@code null} if no handler was bound to the channel
@@ -157,15 +161,15 @@ public final class ClientPlayNetworking {
 	 * Checks if the connected server declared the ability to receive a packet on a specified channel name.
 	 *
 	 * @param channelName the channel name
-	 * @return True if the connected server has declared the ability to receive a packet on the specified channel
-	 * @throws IllegalStateException if the client is not connected to a server
+	 * @return True if the connected server has declared the ability to receive a packet on the specified channel.
+	 * False if the client is not in game.
 	 */
 	public static boolean canSend(Identifier channelName) throws IllegalArgumentException {
 		if (MinecraftClient.getInstance().getNetworkHandler() != null) {
 			return ClientNetworkingImpl.getAddon(MinecraftClient.getInstance().getNetworkHandler()).getSendableChannels().contains(channelName);
 		}
 
-		throw new IllegalStateException("Cannot check whether the server can receive a packet while not in game!");
+		return false;
 	}
 
 	/**

fabric-networking-api-v1/src/main/java/net/fabricmc/fabric/api/networking/v1/ServerLoginConnectionEvents.java

@@ -28,14 +28,12 @@ import net.fabricmc.fabric.api.event.EventFactory;
  */
 public final class ServerLoginConnectionEvents {
 	/**
-	 * An event for the initialization of the server login network handler.
-	 * This event may be used to register {@link ServerLoginNetworking.LoginQueryResponseHandler login query response handlers}
-	 * using {@link ServerLoginNetworking#registerReceiver(ServerLoginNetworkHandler, Identifier, ServerLoginNetworking.LoginQueryResponseHandler)}.
+	 * Event indicating a connection entered the LOGIN state, ready for registering query response handlers.
 	 *
-	 * <p>No packets should be sent when this event is invoked.
+	 * @see ServerLoginNetworking#registerReceiver(ServerLoginNetworkHandler, Identifier, ServerLoginNetworking.LoginQueryResponseHandler)
 	 */
-	public static final Event<LoginInit> LOGIN_INIT = EventFactory.createArrayBacked(LoginInit.class, callbacks -> (handler, server) -> {
-		for (LoginInit callback : callbacks) {
+	public static final Event<Init> INIT = EventFactory.createArrayBacked(Init.class, callbacks -> (handler, server) -> {
+		for (Init callback : callbacks) {
 			callback.onLoginInit(handler, server);
 		}
 	});
@@ -48,8 +46,8 @@ public final class ServerLoginConnectionEvents {
 	 *
 	 * <p>You may send login queries to the connected client using the provided {@link PacketSender}.
 	 */
-	public static final Event<LoginQueryStart> LOGIN_QUERY_START = EventFactory.createArrayBacked(LoginQueryStart.class, callbacks -> (handler, server, sender, synchronizer) -> {
-		for (LoginQueryStart callback : callbacks) {
+	public static final Event<QueryStart> QUERY_START = EventFactory.createArrayBacked(QueryStart.class, callbacks -> (handler, server, sender, synchronizer) -> {
+		for (QueryStart callback : callbacks) {
 			callback.onLoginStart(handler, server, sender, synchronizer);
 		}
 	});
@@ -59,8 +57,8 @@ public final class ServerLoginConnectionEvents {
 	 *
 	 * <p>No packets should be sent when this event is invoked.
 	 */
-	public static final Event<LoginDisconnect> LOGIN_DISCONNECT = EventFactory.createArrayBacked(LoginDisconnect.class, callbacks -> (handler, server) -> {
-		for (LoginDisconnect callback : callbacks) {
+	public static final Event<Disconnect> DISCONNECT = EventFactory.createArrayBacked(Disconnect.class, callbacks -> (handler, server) -> {
+		for (Disconnect callback : callbacks) {
 			callback.onLoginDisconnect(handler, server);
 		}
 	});
@@ -69,26 +67,26 @@ public final class ServerLoginConnectionEvents {
 	}
 
 	/**
-	 * @see ServerLoginConnectionEvents#LOGIN_INIT
+	 * @see ServerLoginConnectionEvents#INIT
 	 */
 	@FunctionalInterface
-	public interface LoginInit {
+	public interface Init {
 		void onLoginInit(ServerLoginNetworkHandler handler, MinecraftServer server);
 	}
 
 	/**
-	 * @see ServerLoginConnectionEvents#LOGIN_QUERY_START
+	 * @see ServerLoginConnectionEvents#QUERY_START
 	 */
 	@FunctionalInterface
-	public interface LoginQueryStart {
+	public interface QueryStart {
 		void onLoginStart(ServerLoginNetworkHandler handler, MinecraftServer server, PacketSender sender, ServerLoginNetworking.LoginSynchronizer synchronizer);
 	}
 
 	/**
-	 * @see ServerLoginConnectionEvents#LOGIN_DISCONNECT
+	 * @see ServerLoginConnectionEvents#DISCONNECT
 	 */
 	@FunctionalInterface
-	public interface LoginDisconnect {
+	public interface Disconnect {
 		void onLoginDisconnect(ServerLoginNetworkHandler handler, MinecraftServer server);
 	}
 }

fabric-networking-api-v1/src/main/java/net/fabricmc/fabric/api/networking/v1/ServerLoginNetworking.java

@@ -88,7 +88,7 @@ public final class ServerLoginNetworking {
 	 * Registers a handler to a query response channel.
 	 *
 	 * <p>If a handler is already registered to the {@code channelName}, this method will return {@code false}, and no change will be made.
-	 * Use {@link #unregisterReceiver(ServerLoginNetworkHandler, Identifier)} to unregister the existing handler.</p>
+	 * Use {@link #unregisterReceiver(ServerLoginNetworkHandler, Identifier)} to unregister the existing handler.
 	 *
 	 * @param networkHandler the handler
 	 * @param channelName the id of the channel
@@ -104,7 +104,7 @@ public final class ServerLoginNetworking {
 	/**
 	 * Removes the handler of a query response channel.
 	 *
-	 * <p>The {@code channelName} is guaranteed not to have a handler after this call.</p>
+	 * <p>The {@code channelName} is guaranteed not to have a handler after this call.
 	 *
 	 * @param channelName the id of the channel
 	 * @return the previous handler, or {@code null} if no handler was bound to the channel name

fabric-networking-api-v1/src/main/java/net/fabricmc/fabric/api/networking/v1/ServerPlayConnectionEvents.java

@@ -18,6 +18,7 @@ package net.fabricmc.fabric.api.networking.v1;
 
 import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.network.ServerPlayNetworkHandler;
+import net.minecraft.util.Identifier;
 
 import net.fabricmc.fabric.api.event.Event;
 import net.fabricmc.fabric.api.event.EventFactory;
@@ -27,23 +28,34 @@ import net.fabricmc.fabric.api.event.EventFactory;
  */
 public final class ServerPlayConnectionEvents {
 	/**
-	 * An event for the initialization of the server play network handler.
+	 * Event indicating a connection entered the PLAY state, ready for registering channel handlers.
+	 *
+	 * @see ServerPlayNetworking#registerReceiver(ServerPlayNetworkHandler, Identifier, ServerPlayNetworking.PlayChannelHandler)
+	 */
+	public static final Event<Init> INIT = EventFactory.createArrayBacked(Init.class, callbacks -> (handler, server) -> {
+		for (Init callback : callbacks) {
+			callback.onPlayInit(handler, server);
+		}
+	});
+
+	/**
+	 * An event for notification when the server play network handler is ready to send packets to the client.
 	 *
 	 * <p>At this stage, the network handler is ready to send packets to the client.
 	 */
-	public static final Event<PlayInit> PLAY_INIT = EventFactory.createArrayBacked(PlayInit.class, callbacks -> (handler, sender, server) -> {
-		for (PlayInit callback : callbacks) {
-			callback.onPlayInit(handler, sender, server);
+	public static final Event<Join> JOIN = EventFactory.createArrayBacked(Join.class, callbacks -> (handler, sender, server) -> {
+		for (Join callback : callbacks) {
+			callback.onPlayReady(handler, sender, server);
 		}
 	});
 
 	/**
 	 * An event for the disconnection of the server play network handler.
 	 *
-	 * <p>No packets should be sent when this event is invoked.</p>
+	 * <p>No packets should be sent when this event is invoked.
 	 */
-	public static final Event<PlayDisconnect> PLAY_DISCONNECT = EventFactory.createArrayBacked(PlayDisconnect.class, callbacks -> (handler, server) -> {
-		for (PlayDisconnect callback : callbacks) {
+	public static final Event<Disconnect> DISCONNECT = EventFactory.createArrayBacked(Disconnect.class, callbacks -> (handler, server) -> {
+		for (Disconnect callback : callbacks) {
 			callback.onPlayDisconnect(handler, server);
 		}
 	});
@@ -52,12 +64,17 @@ public final class ServerPlayConnectionEvents {
 	}
 
 	@FunctionalInterface
-	public interface PlayInit {
-		void onPlayInit(ServerPlayNetworkHandler handler, PacketSender sender, MinecraftServer server);
+	public interface Init {
+		void onPlayInit(ServerPlayNetworkHandler handler, MinecraftServer server);
 	}
 
 	@FunctionalInterface
-	public interface PlayDisconnect {
+	public interface Join {
+		void onPlayReady(ServerPlayNetworkHandler handler, PacketSender sender, MinecraftServer server);
+	}
+
+	@FunctionalInterface
+	public interface Disconnect {
 		void onPlayDisconnect(ServerPlayNetworkHandler handler, MinecraftServer server);
 	}
 }

fabric-networking-api-v1/src/main/java/net/fabricmc/fabric/api/networking/v1/ServerPlayNetworking.java

@@ -48,7 +48,7 @@ public final class ServerPlayNetworking {
 	 * A global receiver is registered to all connections, in the present and future.
 	 *
 	 * <p>If a handler is already registered to the {@code channel}, this method will return {@code false}, and no change will be made.
-	 * Use {@link #unregisterReceiver(ServerPlayNetworkHandler, Identifier)} to unregister the existing handler.</p>
+	 * Use {@link #unregisterReceiver(ServerPlayNetworkHandler, Identifier)} to unregister the existing handler.
 	 *
 	 * @param channelName the id of the channel
 	 * @param channelHandler the handler
@@ -64,7 +64,7 @@ public final class ServerPlayNetworking {
 	 * Removes the handler of a channel.
 	 * A global receiver is registered to all connections, in the present and future.
 	 *
-	 * <p>The {@code channel} is guaranteed not to have a handler after this call.</p>
+	 * <p>The {@code channel} is guaranteed not to have a handler after this call.
 	 *
 	 * @param channelName the id of the channel
 	 * @return the previous handler, or {@code null} if no handler was bound to the channel
@@ -88,14 +88,20 @@ public final class ServerPlayNetworking {
 
 	/**
 	 * Registers a handler to a channel.
+	 * This method differs from {@link ServerPlayNetworking#registerGlobalReceiver(Identifier, PlayChannelHandler)} since
+	 * the channel handler will only be applied to the player represented by the {@link ServerPlayNetworkHandler}.
+	 *
+	 * <p>For example, if you only register a receiver using this method when a {@linkplain ServerLoginNetworking#registerGlobalReceiver(Identifier, ServerLoginNetworking.LoginQueryResponseHandler)}
+	 * login response has been received, you should use {@link ServerPlayConnectionEvents#INIT} to register the channel handler.
 	 *
 	 * <p>If a handler is already registered to the {@code channelName}, this method will return {@code false}, and no change will be made.
-	 * Use {@link #unregisterReceiver(ServerPlayNetworkHandler, Identifier)} to unregister the existing handler.</p>
+	 * Use {@link #unregisterReceiver(ServerPlayNetworkHandler, Identifier)} to unregister the existing handler.
 	 *
 	 * @param networkHandler the handler
 	 * @param channelName the id of the channel
 	 * @param channelHandler the handler
 	 * @return false if a handler is already registered to the channel name
+	 * @see ServerPlayConnectionEvents#INIT
 	 */
 	public static boolean registerReceiver(ServerPlayNetworkHandler networkHandler, Identifier channelName, PlayChannelHandler channelHandler) {
 		Objects.requireNonNull(networkHandler, "Network handler cannot be null");
@@ -106,7 +112,7 @@ public final class ServerPlayNetworking {
 	/**
 	 * Removes the handler of a channel.
 	 *
-	 * <p>The {@code channelName} is guaranteed not to have a handler after this call.</p>
+	 * <p>The {@code channelName} is guaranteed not to have a handler after this call.
 	 *
 	 * @param channelName the id of the channel
 	 * @return the previous handler, or {@code null} if no handler was bound to the channel name

fabric-networking-api-v1/src/main/java/net/fabricmc/fabric/impl/networking/AbstractChanneledNetworkAddon.java

@@ -106,7 +106,7 @@ public abstract class AbstractChanneledNetworkAddon<H> extends AbstractNetworkAd
 
 	protected abstract void receive(H handler, PacketByteBuf buf);
 
-	public void sendChannelRegistrationPacket() {
+	protected void sendInitialChannelRegistrationPacket() {
 		final PacketByteBuf buf = this.createRegistrationPacket(this.receiver.getChannels());
 
 		if (buf != null) {

fabric-networking-api-v1/src/main/java/net/fabricmc/fabric/impl/networking/NetworkingImpl.java

@@ -50,7 +50,7 @@ public final class NetworkingImpl {
 
 	public static void init() {
 		// Login setup
-		ServerLoginConnectionEvents.LOGIN_QUERY_START.register((handler, server, sender, synchronizer) -> {
+		ServerLoginConnectionEvents.QUERY_START.register((handler, server, sender, synchronizer) -> {
 			// Send early registration packet
 			PacketByteBuf buf = PacketByteBufs.create();
 			Collection<Identifier> channelsNames = ServerPlayNetworking.getGlobalReceivers();

fabric-networking-api-v1/src/main/java/net/fabricmc/fabric/impl/networking/client/ClientLoginNetworkAddon.java

@@ -52,7 +52,7 @@ public final class ClientLoginNetworkAddon extends AbstractNetworkAddon<ClientLo
 		this.handler = handler;
 		this.client = client;
 
-		ClientLoginConnectionEvents.LOGIN_INIT.invoker().onLoginStart(this.handler, this.client);
+		ClientLoginConnectionEvents.INIT.invoker().onLoginStart(this.handler, this.client);
 		this.receiver.startSession(this);
 	}
 
@@ -70,7 +70,7 @@ public final class ClientLoginNetworkAddon extends AbstractNetworkAddon<ClientLo
 				ClientLoginNetworking.registerReceiver(entry.getKey(), entry.getValue());
 			}
 
-			ClientLoginConnectionEvents.LOGIN_QUERY_START.invoker().onLoginQueryStart(this.handler, this.client);
+			ClientLoginConnectionEvents.QUERY_START.invoker().onLoginQueryStart(this.handler, this.client);
 			this.firstResponse = false;
 		}
 
@@ -113,7 +113,7 @@ public final class ClientLoginNetworkAddon extends AbstractNetworkAddon<ClientLo
 
 	@Override
 	public void invokeDisconnectEvent() {
-		ClientLoginConnectionEvents.LOGIN_DISCONNECT.invoker().onLoginDisconnect(this.handler, this.client);
+		ClientLoginConnectionEvents.DISCONNECT.invoker().onLoginDisconnect(this.handler, this.client);
 		this.receiver.endSession(this);
 	}
 

fabric-networking-api-v1/src/main/java/net/fabricmc/fabric/impl/networking/client/ClientPlayNetworkAddon.java

@@ -40,7 +40,7 @@ import net.fabricmc.fabric.impl.networking.NetworkingImpl;
 public final class ClientPlayNetworkAddon extends AbstractChanneledNetworkAddon<ClientPlayNetworking.PlayChannelHandler> {
 	private final ClientPlayNetworkHandler handler;
 	private final MinecraftClient client;
-	private boolean canSendPackets;
+	private boolean sentInitialRegisterPacket;
 
 	public ClientPlayNetworkAddon(ClientPlayNetworkHandler handler, MinecraftClient client) {
 		super(ClientNetworkingImpl.PLAY, handler.getConnection(), "ClientPlayNetworkAddon for " + handler.getProfile().getName());
@@ -49,21 +49,23 @@ public final class ClientPlayNetworkAddon extends AbstractChanneledNetworkAddon<
 
 		// Must register pending channels via lateinit
 		this.registerPendingChannels((ChannelInfoHolder) this.connection);
-	}
 
-	// also expose sendRegistration
+		// Register global receivers and attach to session
+		this.receiver.startSession(this);
 
-	public void onServerReady() {
-		// Register global receivers
-		for (Map.Entry<Identifier, ClientPlayNetworking.PlayChannelHandler> entry : ClientNetworkingImpl.PLAY.getHandlers().entrySet()) {
+		for (Map.Entry<Identifier, ClientPlayNetworking.PlayChannelHandler> entry : this.receiver.getHandlers().entrySet()) {
 			this.registerChannel(entry.getKey(), entry.getValue());
 		}
 
-		this.sendChannelRegistrationPacket();
-		this.canSendPackets = true;
+		ClientPlayConnectionEvents.INIT.invoker().onPlayInit(handler, this.client);
+	}
 
-		ClientPlayConnectionEvents.PLAY_INIT.invoker().onPlayInit(this.handler, this, this.client);
-		this.receiver.startSession(this);
+	public void onServerReady() {
+		ClientPlayConnectionEvents.JOIN.invoker().onPlayReady(this.handler, this, this.client);
+
+		// The client cannot send any packets, including `minecraft:register` until after GameJoinS2CPacket is received.
+		this.sendInitialChannelRegistrationPacket();
+		this.sentInitialRegisterPacket = true;
 	}
 
 	/**
@@ -73,6 +75,11 @@ public final class ClientPlayNetworkAddon extends AbstractChanneledNetworkAddon<
 	 * @return true if the packet has been handled
 	 */
 	public boolean handle(CustomPayloadS2CPacket packet) {
+		// Do not handle the packet on game thread
+		if (this.client.isOnThread()) {
+			return false;
+		}
+
 		PacketByteBuf buf = packet.getData();
 
 		try {
@@ -112,7 +119,7 @@ public final class ClientPlayNetworkAddon extends AbstractChanneledNetworkAddon<
 	@Override
 	protected void handleRegistration(Identifier channelName) {
 		// If we can already send packets, immediately send the register packet for this channel
-		if (this.canSendPackets) {
+		if (this.sentInitialRegisterPacket) {
 			final PacketByteBuf buf = this.createRegistrationPacket(Collections.singleton(channelName));
 
 			if (buf != null) {
@@ -124,7 +131,7 @@ public final class ClientPlayNetworkAddon extends AbstractChanneledNetworkAddon<
 	@Override
 	protected void handleUnregistration(Identifier channelName) {
 		// If we can already send packets, immediately send the unregister packet for this channel
-		if (this.canSendPackets) {
+		if (this.sentInitialRegisterPacket) {
 			final PacketByteBuf buf = this.createRegistrationPacket(Collections.singleton(channelName));
 
 			if (buf != null) {
@@ -135,7 +142,7 @@ public final class ClientPlayNetworkAddon extends AbstractChanneledNetworkAddon<
 
 	@Override
 	public void invokeDisconnectEvent() {
-		ClientPlayConnectionEvents.PLAY_DISCONNECT.invoker().onPlayDisconnect(this.handler, this.client);
+		ClientPlayConnectionEvents.DISCONNECT.invoker().onPlayDisconnect(this.handler, this.client);
 		this.receiver.endSession(this);
 	}
 

fabric-networking-api-v1/src/main/java/net/fabricmc/fabric/impl/networking/server/ServerLoginNetworkAddon.java

@@ -64,7 +64,7 @@ public final class ServerLoginNetworkAddon extends AbstractNetworkAddon<ServerLo
 		this.server = ((ServerLoginNetworkHandlerAccessor) handler).getServer();
 		this.queryIdFactory = QueryIdFactory.create();
 
-		ServerLoginConnectionEvents.LOGIN_INIT.invoker().onLoginInit(handler, this.server);
+		ServerLoginConnectionEvents.INIT.invoker().onLoginInit(handler, this.server);
 		this.receiver.startSession(this);
 	}
 
@@ -79,7 +79,7 @@ public final class ServerLoginNetworkAddon extends AbstractNetworkAddon<ServerLo
 				ServerLoginNetworking.registerReceiver(this.handler, entry.getKey(), entry.getValue());
 			}
 
-			ServerLoginConnectionEvents.LOGIN_QUERY_START.invoker().onLoginStart(this.handler, this.server, this, this.waits::add);
+			ServerLoginConnectionEvents.QUERY_START.invoker().onLoginStart(this.handler, this.server, this, this.waits::add);
 			this.firstQueryTick = false;
 		}
 
@@ -200,7 +200,7 @@ public final class ServerLoginNetworkAddon extends AbstractNetworkAddon<ServerLo
 
 	@Override
 	public void invokeDisconnectEvent() {
-		ServerLoginConnectionEvents.LOGIN_DISCONNECT.invoker().onLoginDisconnect(this.handler, this.server);
+		ServerLoginConnectionEvents.DISCONNECT.invoker().onLoginDisconnect(this.handler, this.server);
 		this.receiver.endSession(this);
 	}
 

fabric-networking-api-v1/src/main/java/net/fabricmc/fabric/impl/networking/server/ServerPlayNetworkAddon.java

@@ -38,7 +38,7 @@ import net.fabricmc.fabric.mixin.networking.accessor.CustomPayloadC2SPacketAcces
 public final class ServerPlayNetworkAddon extends AbstractChanneledNetworkAddon<ServerPlayNetworking.PlayChannelHandler> {
 	private final ServerPlayNetworkHandler handler;
 	private final MinecraftServer server;
-	private boolean canSendPackets = false;
+	private boolean sentInitialRegisterPacket;
 
 	public ServerPlayNetworkAddon(ServerPlayNetworkHandler handler, MinecraftServer server) {
 		super(ServerNetworkingImpl.PLAY, handler.getConnection(), "ServerPlayNetworkAddon for " + handler.player.getEntityName());
@@ -47,19 +47,22 @@ public final class ServerPlayNetworkAddon extends AbstractChanneledNetworkAddon<
 
 		// Must register pending channels via lateinit
 		this.registerPendingChannels((ChannelInfoHolder) this.connection);
-	}
 
-	public void onClientReady() {
-		// Register global receivers
-		for (Map.Entry<Identifier, ServerPlayNetworking.PlayChannelHandler> entry : ServerNetworkingImpl.PLAY.getHandlers().entrySet()) {
+		// Register global receivers and attach to session
+		this.receiver.startSession(this);
+
+		for (Map.Entry<Identifier, ServerPlayNetworking.PlayChannelHandler> entry : this.receiver.getHandlers().entrySet()) {
 			this.registerChannel(entry.getKey(), entry.getValue());
 		}
 
-		this.sendChannelRegistrationPacket();
-		this.canSendPackets = true;
+		ServerPlayConnectionEvents.INIT.invoker().onPlayInit(this.handler, this.server);
+	}
 
-		ServerPlayConnectionEvents.PLAY_INIT.invoker().onPlayInit(this.handler, this, this.server);
-		this.receiver.startSession(this);
+	public void onClientReady() {
+		ServerPlayConnectionEvents.JOIN.invoker().onPlayReady(this.handler, this, this.server);
+
+		this.sendInitialChannelRegistrationPacket();
+		this.sentInitialRegisterPacket = true;
 	}
 
 	/**
@@ -69,6 +72,11 @@ public final class ServerPlayNetworkAddon extends AbstractChanneledNetworkAddon<
 	 * @return true if the packet has been handled
 	 */
 	public boolean handle(CustomPayloadC2SPacket packet) {
+		// Do not handle the packet on game thread
+		if (this.server.isOnThread()) {
+			return false;
+		}
+
 		CustomPayloadC2SPacketAccessor access = (CustomPayloadC2SPacketAccessor) packet;
 		return this.handle(access.getChannel(), access.getData());
 	}
@@ -103,7 +111,7 @@ public final class ServerPlayNetworkAddon extends AbstractChanneledNetworkAddon<
 	@Override
 	protected void handleRegistration(Identifier channelName) {
 		// If we can already send packets, immediately send the register packet for this channel
-		if (this.canSendPackets) {
+		if (this.sentInitialRegisterPacket) {
 			final PacketByteBuf buf = this.createRegistrationPacket(Collections.singleton(channelName));
 
 			if (buf != null) {
@@ -115,7 +123,7 @@ public final class ServerPlayNetworkAddon extends AbstractChanneledNetworkAddon<
 	@Override
 	protected void handleUnregistration(Identifier channelName) {
 		// If we can already send packets, immediately send the unregister packet for this channel
-		if (this.canSendPackets) {
+		if (this.sentInitialRegisterPacket) {
 			final PacketByteBuf buf = this.createRegistrationPacket(Collections.singleton(channelName));
 
 			if (buf != null) {
@@ -126,7 +134,7 @@ public final class ServerPlayNetworkAddon extends AbstractChanneledNetworkAddon<
 
 	@Override
 	public void invokeDisconnectEvent() {
-		ServerPlayConnectionEvents.PLAY_DISCONNECT.invoker().onPlayDisconnect(this.handler, this.server);
+		ServerPlayConnectionEvents.DISCONNECT.invoker().onPlayDisconnect(this.handler, this.server);
 		this.receiver.endSession(this);
 	}
 

fabric-networking-api-v1/src/testmod/java/net/fabricmc/fabric/test/networking/channeltest/NetworkingChannelClientTest.java

@@ -64,11 +64,11 @@ public final class NetworkingChannelClientTest implements ClientModInitializer {
 		});
 
 		// State destruction on disconnection:
-		ClientLoginConnectionEvents.LOGIN_DISCONNECT.register((handler, client) -> {
+		ClientLoginConnectionEvents.DISCONNECT.register((handler, client) -> {
 			SUPPORTED_C2S_CHANNELS.clear();
 		});
 
-		ClientPlayConnectionEvents.PLAY_DISCONNECT.register((handler, client) -> {
+		ClientPlayConnectionEvents.DISCONNECT.register((handler, client) -> {
 			SUPPORTED_C2S_CHANNELS.clear();
 		});
 	}

fabric-networking-api-v1/src/testmod/java/net/fabricmc/fabric/test/networking/keybindreciever/NetworkingKeybindPacketTest.java

@@ -45,7 +45,7 @@ public final class NetworkingKeybindPacketTest implements ModInitializer {
 
 	@Override
 	public void onInitialize() {
-		ServerPlayConnectionEvents.PLAY_INIT.register((handler, sender, server) -> {
+		ServerPlayConnectionEvents.INIT.register((handler, server) -> {
 			ServerPlayNetworking.registerReceiver(handler, KEYBINDING_PACKET_ID, NetworkingKeybindPacketTest::receive);
 		});
 	}

fabric-networking-api-v1/src/testmod/java/net/fabricmc/fabric/test/networking/login/NetworkingLoginQueryTest.java

@@ -36,8 +36,8 @@ public final class NetworkingLoginQueryTest implements ModInitializer {
 
 	@Override
 	public void onInitialize() {
-		ServerLoginConnectionEvents.LOGIN_QUERY_START.register(this::onLoginStart);
-		ServerLoginConnectionEvents.LOGIN_QUERY_START.register(this::delaySimply);
+		ServerLoginConnectionEvents.QUERY_START.register(this::onLoginStart);
+		ServerLoginConnectionEvents.QUERY_START.register(this::delaySimply);
 
 		// login delaying example
 		ServerLoginNetworking.registerGlobalReceiver(NetworkingPlayPacketTest.TEST_CHANNEL, (server, handler, understood, buf, synchronizer, sender) -> {

fabric-networking-api-v1/src/testmod/java/net/fabricmc/fabric/test/networking/play/NetworkingPlayPacketClientTest.java

@@ -31,7 +31,7 @@ public final class NetworkingPlayPacketClientTest implements ClientModInitialize
 	public void onInitializeClient() {
 		//ClientPlayNetworking.registerGlobalReceiver(NetworkingPlayPacketTest.TEST_CHANNEL, this::receive);
 
-		ClientPlayConnectionEvents.PLAY_INIT.register((handler, sender, client) -> {
+		ClientPlayConnectionEvents.INIT.register((handler, client) -> {
 			ClientPlayNetworking.registerReceiver(NetworkingPlayPacketTest.TEST_CHANNEL, (client1, handler1, buf, sender1) -> receive(handler1, sender1, client1, buf));
 		});
 	}