#479033853

Committed 06 Nov 2026 12:50PM UTC coverage: 23.052% (+0.005%) from 23.047%

Build # #479033853

Build Type

Pull #259

github

Committed by

claude

Commit Message

Log packet encoding and decoding errors

When a packet fails to encode or decode, vanilla disconnects with
"Internal Exception" but only logs the cause at debug level, so it is
missing from latest.log. Log the full stack trace at error level, so
these disconnects can be diagnosed from regular logs.

The decoding error now names the packet class instead of a fresh
instance's toString, which also avoids an NPE when construction failed.

Related to #258

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UeSuG8Sp4V22VPUqWFGwM7

Pull Request Pull Request #259: Fix packets failing to decode when a map is modified while encoding, and log codec errors

Coverage Stats

2 of 6 new or added lines in 2 files covered. (33.33%)

28 existing lines in 1 file now uncovered.

2444 of 10602 relevant lines covered (23.05%)

0.23 hits per line

Source File
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0.0

/src/main/java/org/cyclops/cyclopscore/network/PacketHandler.java

package org.cyclops.cyclopscore.network;

import com.google.common.base.Predicates;
import io.netty.channel.ChannelHandler.Sharable;
import net.minecraft.client.Minecraft;
import net.minecraft.client.player.LocalPlayer;
import net.minecraft.resources.ResourceKey;
import net.minecraft.resources.ResourceLocation;
import net.minecraft.server.level.ServerPlayer;
import net.minecraft.world.level.Level;
import net.minecraftforge.api.distmarker.Dist;
import net.minecraftforge.api.distmarker.OnlyIn;
import net.minecraftforge.network.NetworkDirection;
import net.minecraftforge.network.NetworkEvent;
import net.minecraftforge.network.NetworkRegistry;
import net.minecraftforge.network.PacketDistributor;
import net.minecraftforge.network.simple.SimpleChannel;
import org.cyclops.cyclopscore.CyclopsCore;
import org.cyclops.cyclopscore.helper.Helpers;
import org.cyclops.cyclopscore.helper.Helpers.IDType;
import org.cyclops.cyclopscore.init.ModBase;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;

/**
 * Advanced packet handler of {@link PacketBase} instances.
 * An alternative would be {@link SimpleChannel}.
 * @author rubensworks
 */
@Sharable
public final class PacketHandler {

    private final ModBase mod;

    private SimpleChannel networkChannel = null;

    public PacketHandler(ModBase mod) {
        this.mod = mod;
    }

    public void init() {
        if(networkChannel == null) {
            networkChannel = NetworkRegistry.newSimpleChannel(
                    new ResourceLocation(mod.getModId(), "channel_main"), () -> "1.0.0",
                    Predicates.alwaysTrue(), Predicates.alwaysTrue());
        }
    }

    /**
     * Register a new packet.
     * @param packetType The class of the packet.
     * @param <P> The packet type.
     */
    public <P extends PacketBase> void register(Class<P> packetType) {
        int discriminator = Helpers.getNewId(mod, IDType.PACKET);
        try {
            Constructor<P> constructor = packetType.getConstructor();
            networkChannel.registerMessage(discriminator, packetType,
                    (packet, packetBuffer) -> {
                        try {
                            packet.encode(packetBuffer);
                        } catch (Throwable e) {
                            throw logCodecException("An exception occurred during encoding of packet " + packet.toString(), e);
                        }
                    },
                    (packetBuffer) -> {
                        P packet = null;
                        try {
                            packet = constructor.newInstance();
                        } catch (InstantiationException | IllegalAccessException | InvocationTargetException e) {
                            e.printStackTrace();
                        }
                        try {
                            packet.decode(packetBuffer);
                        } catch (Throwable e) {
                            throw logCodecException("An exception occurred during decoding of packet " + packetType.getName(), e);
                        }
                        return packet;
                    },
                    (packet, contextSupplier) -> {
                        NetworkEvent.Context context = contextSupplier.get();
                        if (context.getDirection().getReceptionSide().isClient()) {
                            if (packet.isAsync()) {
                                handlePacketClient(context, packet);
                            } else {
                                context.enqueueWork(() -> handlePacketClient(context, packet));
                            }
                        } else {
                            if (packet.isAsync()) {
                                handlePacketServer(context, packet);
                            } else {
                                context.enqueueWork(() -> handlePacketServer(context, packet));
                            }
                        }
                        context.setPacketHandled(true);
                    });
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
            CyclopsCore.clog(org.apache.logging.log4j.Level.ERROR, "Could not find a default constructor for packet " + packetType.getName());
        }
    }

    // Vanilla only logs the cause at debug level when disconnecting, so log it here.
    private PacketCodecException logCodecException(String message, Throwable cause) {
        mod.getLoggerHelper().getLogger().error(message, cause);
        return new PacketCodecException(message, cause);
    }

    @OnlyIn(Dist.CLIENT)
    public void handlePacketClient(NetworkEvent.Context context, PacketBase packet) {
        LocalPlayer player = Minecraft.getInstance().player;
        packet.actionClient(player != null ? player.level() : null, player);
    }

    public void handlePacketServer(NetworkEvent.Context context, PacketBase packet) {
        packet.actionServer(context.getSender().level(), context.getSender());
    }

    /**
     * Send a packet to the server.
     * @param packet The packet.
     */
    public void sendToServer(PacketBase packet) {
        networkChannel.sendToServer(packet);
    }

    /**
     * Send a packet to the player.
     * @param packet The packet.
     * @param player The player.
     */
    public void sendToPlayer(PacketBase packet, ServerPlayer player) {
        networkChannel.sendTo(packet, player.connection.connection, NetworkDirection.PLAY_TO_CLIENT);
    }

    /**
     * Send a packet to all in the target range.
     * @param packet The packet.
     * @param point The area to send to.
     */
    public void sendToAllAround(PacketBase packet, PacketDistributor.TargetPoint point) {
        PacketDistributor.PacketTarget target = PacketDistributor.NEAR.with(() -> point);
        target.send(networkChannel.toVanillaPacket(packet, target.getDirection()));
    }

    /**
     * Send a packet to everything in the given dimension.
     * @param packet The packet.
     * @param dimension The dimension to send to.
     */
    public void sendToDimension(PacketBase packet, ResourceKey<Level> dimension) {
        PacketDistributor.PacketTarget target = PacketDistributor.DIMENSION.with(() -> dimension);
        target.send(networkChannel.toVanillaPacket(packet, target.getDirection()));
    }

    /**
     * Send a packet to everything.
     * @param packet The packet.
     */
    public void sendToAll(PacketBase packet) {
        PacketDistributor.PacketTarget target = PacketDistributor.ALL.with(() -> null);
        target.send(networkChannel.toVanillaPacket(packet, target.getDirection()));
    }

    public static class PacketCodecException extends RuntimeException {
        public PacketCodecException(String message, Throwable cause) {
            super(message, cause);
        }
    }

}

1	package org.cyclops.cyclopscore.network;
2
3	import com.google.common.base.Predicates;
4	import io.netty.channel.ChannelHandler.Sharable;
5	import net.minecraft.client.Minecraft;
6	import net.minecraft.client.player.LocalPlayer;
7	import net.minecraft.resources.ResourceKey;
8	import net.minecraft.resources.ResourceLocation;
9	import net.minecraft.server.level.ServerPlayer;
10	import net.minecraft.world.level.Level;
11	import net.minecraftforge.api.distmarker.Dist;
12	import net.minecraftforge.api.distmarker.OnlyIn;
13	import net.minecraftforge.network.NetworkDirection;
14	import net.minecraftforge.network.NetworkEvent;
15	import net.minecraftforge.network.NetworkRegistry;
16	import net.minecraftforge.network.PacketDistributor;
17	import net.minecraftforge.network.simple.SimpleChannel;
18	import org.cyclops.cyclopscore.CyclopsCore;
19	import org.cyclops.cyclopscore.helper.Helpers;
20	import org.cyclops.cyclopscore.helper.Helpers.IDType;
21	import org.cyclops.cyclopscore.init.ModBase;
22
23	import java.lang.reflect.Constructor;
24	import java.lang.reflect.InvocationTargetException;
25
26	/**
27	* Advanced packet handler of {@link PacketBase} instances.
28	* An alternative would be {@link SimpleChannel}.
29	* @author rubensworks
30	*/
31	@Sharable
32	public final class PacketHandler {
33
34	private final ModBase mod;
35
36	private SimpleChannel networkChannel = null;	×
37
38	public PacketHandler(ModBase mod) {	×
39	this.mod = mod;	×
40	}	×
41
42	public void init() {
43	if(networkChannel == null) {	×
44	networkChannel = NetworkRegistry.newSimpleChannel(	×
45	new ResourceLocation(mod.getModId(), "channel_main"), () -> "1.0.0",	×
46	Predicates.alwaysTrue(), Predicates.alwaysTrue());	×
47	}
48	}	×
49
50	/**
51	* Register a new packet.
52	* @param packetType The class of the packet.
53	* @param <P> The packet type.
54	*/
55	public <P extends PacketBase> void register(Class<P> packetType) {
56	int discriminator = Helpers.getNewId(mod, IDType.PACKET);	×
57	try {
58	Constructor<P> constructor = packetType.getConstructor();	×
59	networkChannel.registerMessage(discriminator, packetType,	×
60	(packet, packetBuffer) -> {
61	try {
62	packet.encode(packetBuffer);	×
63	} catch (Throwable e) {	×
NEW 64	throw logCodecException("An exception occurred during encoding of packet " + packet.toString(), e);	×
65	}	×
66	},	×
67	(packetBuffer) -> {
68	P packet = null;	×
69	try {
70	packet = constructor.newInstance();	×
71	} catch (InstantiationException \| IllegalAccessException \| InvocationTargetException e) {	×
72	e.printStackTrace();	×
73	}	×
74	try {
75	packet.decode(packetBuffer);	×
76	} catch (Throwable e) {	×
NEW 77	throw logCodecException("An exception occurred during decoding of packet " + packetType.getName(), e);	×
78	}	×
79	return packet;	×
80	},
81	(packet, contextSupplier) -> {
82	NetworkEvent.Context context = contextSupplier.get();	×
83	if (context.getDirection().getReceptionSide().isClient()) {	×
84	if (packet.isAsync()) {	×
85	handlePacketClient(context, packet);	×
86	} else {
87	context.enqueueWork(() -> handlePacketClient(context, packet));	×
88	}
89	} else {
90	if (packet.isAsync()) {	×
91	handlePacketServer(context, packet);	×
92	} else {
93	context.enqueueWork(() -> handlePacketServer(context, packet));	×
94	}
95	}
96	context.setPacketHandled(true);	×
97	});	×
98	} catch (NoSuchMethodException e) {	×
99	e.printStackTrace();	×
100	CyclopsCore.clog(org.apache.logging.log4j.Level.ERROR, "Could not find a default constructor for packet " + packetType.getName());	×
101	}	×
102	}	×
103
104	// Vanilla only logs the cause at debug level when disconnecting, so log it here.
105	private PacketCodecException logCodecException(String message, Throwable cause) {
NEW 106	mod.getLoggerHelper().getLogger().error(message, cause);	×
NEW 107	return new PacketCodecException(message, cause);	×
108	}
109
110	@OnlyIn(Dist.CLIENT)
111	public void handlePacketClient(NetworkEvent.Context context, PacketBase packet) {
112	LocalPlayer player = Minecraft.getInstance().player;	×
113	packet.actionClient(player != null ? player.level() : null, player);	×
114	}	×
115
116	public void handlePacketServer(NetworkEvent.Context context, PacketBase packet) {
117	packet.actionServer(context.getSender().level(), context.getSender());	×
118	}	×
119
120	/**
121	* Send a packet to the server.
122	* @param packet The packet.
123	*/
124	public void sendToServer(PacketBase packet) {
125	networkChannel.sendToServer(packet);	×
126	}	×
127
128	/**
129	* Send a packet to the player.
130	* @param packet The packet.
131	* @param player The player.
132	*/
133	public void sendToPlayer(PacketBase packet, ServerPlayer player) {
134	networkChannel.sendTo(packet, player.connection.connection, NetworkDirection.PLAY_TO_CLIENT);	×
135	}	×
136
137	/**
138	* Send a packet to all in the target range.
139	* @param packet The packet.
140	* @param point The area to send to.
141	*/
142	public void sendToAllAround(PacketBase packet, PacketDistributor.TargetPoint point) {
143	PacketDistributor.PacketTarget target = PacketDistributor.NEAR.with(() -> point);	×
144	target.send(networkChannel.toVanillaPacket(packet, target.getDirection()));	×
145	}	×
146
147	/**
148	* Send a packet to everything in the given dimension.
149	* @param packet The packet.
150	* @param dimension The dimension to send to.
151	*/
152	public void sendToDimension(PacketBase packet, ResourceKey<Level> dimension) {
153	PacketDistributor.PacketTarget target = PacketDistributor.DIMENSION.with(() -> dimension);	×
154	target.send(networkChannel.toVanillaPacket(packet, target.getDirection()));	×
155	}	×
156
157	/**
158	* Send a packet to everything.
159	* @param packet The packet.
160	*/
161	public void sendToAll(PacketBase packet) {
162	PacketDistributor.PacketTarget target = PacketDistributor.ALL.with(() -> null);	×
163	target.send(networkChannel.toVanillaPacket(packet, target.getDirection()));	×
164	}	×
165
166	public static class PacketCodecException extends RuntimeException {
167	public PacketCodecException(String message, Throwable cause) {
168	super(message, cause);	×
169	}	×
170	}
171
172	}

CyclopsMC / CyclopsCore / #479033853

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