Minecraft Module Sleep Mode

[ssfdre38]

Bug Report

System Information

• Ubuntu 22.04 & 24.04
• 2.5.1.2 20240724.5
• Mainline on both

I confirm:

• that I have searched for an existing bug report for this issue.
• that I am using the latest available version of AMP.
• that my operating system is up-to-date.

Sleep mode on the Minecraft Module is no longer working. Switched to official minecraft server branch, loaded up 1.21, started it up and then press sleep and it fails to sleep. no errors are showing on logs about why its failing

[Gershy13]

Same issue here

[p0t4t0sandwich]

Tested on a couple machines, near identical hardware/software setups, and only one threw the error while attempting to sleep.
Did some sleuthing and found the following:
The ServerData response hasn't changed at all, however, the error in the console regarding vt.a(SourceFile:319) roughly points to:
net.minecraft.network.Connection.send(Packet, PacketSendListener, boolean)

public void send(Packet<?> $$0, @Nullable PacketSendListener $$1, boolean $$2) {
        if (this.isConnected()) { // fails around here for whatever reason (L319)
            this.flushQueue();
            this.sendPacket($$0, $$1, $$2);
        } else {
            this.pendingActions.add($$3 -> {
                $$3.sendPacket($$0, $$1, $$2);
            });
        }
    }

Not sure as to how that's all relevant besides the obvious "connection does packet things".
Working on digging around some more to see if I turn anything else up.

[p0t4t0sandwich]

Found some more fun stuff:
Seemingly at random, my one machine that was putting Vanilla to sleep fine, decided to start throwing the same error.
AMP log (reading is a tad hard due to the interlaced stacktraces from Java + C#):
https://gist.github.com/p0t4t0sandwich/194498826d9aa688a61aa183baa5658f

First the following exception is thrown in IdDispatchCodec.encode:
Sending unknown packet 'clientbound/minecraft:disconnect'

    public void encode(B $$0, V $$1) {
        T $$2 = (T)this.typeGetter.apply($$1);
        int $$3 = this.toId.getOrDefault($$2, -1);
        if ($$3 == -1) { // Throws here because it can't decern the type
            throw new EncoderException("Sending unknown packet '" + $$2 + "'");
        } else {
            VarInt.write($$0, $$3);
            IdDispatchCodec.Entry<B, V, T> $$4 = this.byId.get($$3);

            try {
                StreamCodec<? super B, V> $$5 = (StreamCodec<? super B, V>)$$4.serializer;
                $$5.encode($$0, $$1);
            } catch (Exception var7) {
                throw new EncoderException("Failed to encode packet '" + $$2 + "'", var7);
            }
        }
    }

Which passes up the exception and throws the following inPacketEncoder.encode :
Error sending packet clientbound/minecraft:disconnect

    protected void encode(ChannelHandlerContext $$0, Packet<T> $$1, ByteBuf $$2) throws Exception {
        PacketType<? extends Packet<? super T>> $$3 = $$1.type();

        try {
            this.protocolInfo.codec().encode($$2, $$1); // Throws here due to the exception passed up
            int $$4 = $$2.readableBytes();
            if (LOGGER.isDebugEnabled()) {
                LOGGER.debug(Connection.PACKET_SENT_MARKER, "OUT: [{}:{}] {} -> {} bytes", this.protocolInfo.id().id(), $$3, $$1.getClass().getName(), $$4);
            }

            JvmProfiler.INSTANCE.onPacketSent(this.protocolInfo.id(), $$3, $$0.channel().remoteAddress(), $$4);
        } catch (Throwable var9) {
            LOGGER.error("Error sending packet {}", $$3, var9);
            if ($$1.isSkippable()) {
                throw new SkipPacketException(var9);
            }

            throw var9;
        } finally {
            ProtocolSwapHandler.handleOutboundTerminalPacket($$0, $$1);
        }
    }

It attempts to reply, but AMP doesn't receive the expected response.
Not sure if this is due to an unintentional internal change in AMP, or if it's some race condition.

[IceOfWraith]

I did some quick checking of recent changes and nothing directly changed in the Minecraft module that should cause this behavior. I'll do a deeper dive tomorrow though. Thanks for all the sleuthing!

[IceOfWraith]

I'm not seeing the issue the same on my end. The file error above happens before AMP even starts to go to sleep for me. It does that immediately on startup of the MC server. It's sleeping and waking up fine so far in my testing.

[ssfdre38]

I'm not seeing the issue the same on my end. The file error above happens before AMP even starts to go to sleep for me. It does that immediately on startup of the MC server. It's sleeping and waking up fine so far in my testing.

You can try it on my dev server.

[IceOfWraith]

I see the issue in my dev system.

[p0t4t0sandwich]

Just keeping this thread up to speed on things.
Ice found the following Jira issue: https://bugs.mojang.com/browse/MC-271325?attachmentViewMode=list
This Fabric mods patches the behavior: https://modrinth.com/mod/disconnect-packet-fix
General consensus: The AMP update is most likely a red herring

[MmeCromatique]

The mod does not help with the 1.21 server
Other server versions show the Sleep issue: 1.8.8, 1.20.1, 1.20.4, 1.21

[p0t4t0sandwich]

What server types?

[MmeCromatique]

Respectively Vanilla, Fabric, Fabric, Both

[p0t4t0sandwich]

If the startup times are longer than 25s sleep mode doesn't work, which is why it doesn't work in most modded setups.
What do the AMP logs say for each? Just to check if it's related to this issue, or some different problem.

[MmeCromatique]

It says nothing, no new logs appears, it's like a it is dummy button

[p0t4t0sandwich]

Turn on debug logging inside the instances' settings, then try again. (from the main panel you can right click the instances and hit "View Logs" to see the AMP logs)

[MmeCromatique]

I see this And the server successfully starts in 10 seconds:
[17:17:54] [Server thread/WARN]: Dedicated server took 10.106 seconds to load

[17:17:56] [Minecraft:pmsmp Debug/15] : Sleep client is connecting to 127.0.0.1:25566...
[17:17:56] [Minecraft:pmsmp Warning/15] : Sleep packet timestamp doesn't match! (Expected 1722532676672, got 4706093871785273161)
[17:17:56] [Minecraft:pmsmp Warning/8] : Sleep packet timestamp doesn't match! (Expected 1722532676672, got 7453256651278530379)
[17:17:56] [Minecraft:pmsmp Warning/15] : AMP wasn't able to understand the response from the Minecraft server, sleep mode is not possible.
[17:17:56] [Core:pmsmp Error/15]  : JsonReaderException
[17:17:56] [Core:pmsmp Error/15]  : [0] (JsonReaderException) : Unexpected character encountered while parsing value: A. Path '', line 0, position 0.
[17:17:56] [Minecraft:pmsmp Warning/8] : AMP wasn't able to understand the response from the Minecraft server, sleep mode is not possible.
[17:17:56] [Core:pmsmp Error/8]   : JsonReaderException
[17:17:56] [Core:pmsmp Error/8]   : [0] (JsonReaderException) : Unexpected character encountered while parsing value: �. Path '', line 1, position 1.
[17:17:56] [Core:pmsmp Error/15]  :   at Newtonsoft.Json.JsonTextReader.ParseValue () 
  at Newtonsoft.Json.JsonTextReader.Read () 
  at Newtonsoft.Json.JsonReader.ReadAndMoveToContent () 
  at Newtonsoft.Json.JsonReader.ReadForType (Newtonsoft.Json.Serialization.JsonContract contract, Boolean hasConverter) 
  at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize (Newtonsoft.Json.JsonReader reader, Type objectType, Boolean checkAdditionalContent) 
  at Newtonsoft.Json.JsonSerializer.DeserializeInternal (Newtonsoft.Json.JsonReader reader, Type objectType) 
  at Newtonsoft.Json.JsonSerializer.Deserialize (Newtonsoft.Json.JsonReader reader, Type objectType) 
  at Newtonsoft.Json.JsonConvert.DeserializeObject (String value, Type type, Newtonsoft.Json.JsonSerializerSettings settings) 
  at Newtonsoft.Json.JsonConvert.DeserializeObject[T] (String value, Newtonsoft.Json.JsonSerializerSettings settings) 
  at Newtonsoft.Json.JsonConvert.DeserializeObject[T] (String value) 
  at MinecraftModule.SleepServer.SleepClient.GetServerInfo () 
[17:17:56] [Minecraft:pmsmp Warning/15] : Unable to get protocol version. Sleep mode will be unavailable.
[17:17:56] [Core:pmsmp Error/8]   :   at Newtonsoft.Json.JsonTextReader.ParseValue () 
  at Newtonsoft.Json.JsonTextReader.Read () 
  at Newtonsoft.Json.JsonReader.ReadAndMoveToContent () 
  at Newtonsoft.Json.JsonReader.ReadForType (Newtonsoft.Json.Serialization.JsonContract contract, Boolean hasConverter) 
  at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize (Newtonsoft.Json.JsonReader reader, Type objectType, Boolean checkAdditionalContent) 
  at Newtonsoft.Json.JsonSerializer.DeserializeInternal (Newtonsoft.Json.JsonReader reader, Type objectType) 
  at Newtonsoft.Json.JsonSerializer.Deserialize (Newtonsoft.Json.JsonReader reader, Type objectType) 
  at Newtonsoft.Json.JsonConvert.DeserializeObject (String value, Type type, Newtonsoft.Json.JsonSerializerSettings settings) 
  at Newtonsoft.Json.JsonConvert.DeserializeObject[T] (String value, Newtonsoft.Json.JsonSerializerSettings settings) 
  at Newtonsoft.Json.JsonConvert.DeserializeObject[T] (String value) 
  at MinecraftModule.SleepServer.SleepClient.GetServerInfo () 
[17:17:56] [Minecraft:pmsmp Warning/8] : Unable to get protocol version. Sleep mode will be unavailable.```