Polysit + Polymer Incompat

[Ampflower]

If it's a mod compatibility issue, please provide the link(s) to the incompatible mod(s)

• https://modrinth.com/mod/polysit
• https://modrinth.com/mod/polymer
• Minecraft 1.21.1
• Minecraft 1.20.1 according to Trying to sit on server with polysit and immersive portals cause player to be locked out Modflower/polysit#14

Minecraft version

1.21.1

Describe the issue

Severe, player kick:

• Sitting with /sit at all causes an immediate client kick by bad packet decoding error.
  • This has been reported at Trying to sit on server with polysit and immersive portals cause player to be locked out Modflower/polysit#14 for 1.20.1.
  • This still occurs in 1.21.1.
  • This occurs regardless of singleplayer or multiplayer.
  • A similar report has been reported before at Incompatibility with Polymer-Bundled #1633 so it's possibly caused by that.

Logs:

The log from 1.21.1

[20:46:17] [Netty Local Client IO #1/INFO]: (This is for debugging only. You can ignore that. Logging limit 2/5) Exception from connection: 
io.netty.handler.codec.DecoderException: Failed to decode packet 'clientbound/minecraft:custom_payload'
	at knot/net.minecraft.class_9136.method_56425(class_9136.java:38) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_9136.decode(class_9136.java:14) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_2543.decode(class_2543.java:31) ~[client-intermediary.jar:?]
	at knot/io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:529) ~[netty-codec-4.1.97.Final.jar:?]
	at knot/io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:468) ~[netty-codec-4.1.97.Final.jar:?]
	at knot/io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:290) ~[netty-codec-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.handler.flow.FlowControlHandler.dequeue(FlowControlHandler.java:202) ~[netty-handler-4.1.97.Final.jar:?]
	at knot/io.netty.handler.flow.FlowControlHandler.channelRead(FlowControlHandler.java:164) ~[netty-handler-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:442) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:440) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.local.LocalChannel.readInbound(LocalChannel.java:299) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.local.LocalChannel.doBeginRead(LocalChannel.java:322) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannel$AbstractUnsafe.beginRead(AbstractChannel.java:834) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultChannelPipeline$HeadContext.read(DefaultChannelPipeline.java:1362) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeRead(AbstractChannelHandlerContext.java:835) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.read(AbstractChannelHandlerContext.java:814) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.handler.flow.FlowControlHandler.read(FlowControlHandler.java:144) ~[netty-handler-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeRead(AbstractChannelHandlerContext.java:837) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.read(AbstractChannelHandlerContext.java:814) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultChannelPipeline.read(DefaultChannelPipeline.java:1004) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannel.read(AbstractChannel.java:290) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultChannelPipeline$HeadContext.readIfIsAutoRead(DefaultChannelPipeline.java:1422) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultChannelPipeline$HeadContext.channelReadComplete(DefaultChannelPipeline.java:1417) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeChannelReadComplete(AbstractChannelHandlerContext.java:482) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeChannelReadComplete(AbstractChannelHandlerContext.java:463) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultChannelPipeline.fireChannelReadComplete(DefaultChannelPipeline.java:925) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.local.LocalChannel.readInbound(LocalChannel.java:302) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.local.LocalChannel.doBeginRead(LocalChannel.java:322) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannel$AbstractUnsafe.beginRead(AbstractChannel.java:834) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultChannelPipeline$HeadContext.read(DefaultChannelPipeline.java:1362) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeRead(AbstractChannelHandlerContext.java:835) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.read(AbstractChannelHandlerContext.java:814) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.handler.flow.FlowControlHandler.read(FlowControlHandler.java:144) ~[netty-handler-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeRead(AbstractChannelHandlerContext.java:837) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.read(AbstractChannelHandlerContext.java:814) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultChannelPipeline.read(DefaultChannelPipeline.java:1004) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannel.read(AbstractChannel.java:290) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultChannelPipeline$HeadContext.readIfIsAutoRead(DefaultChannelPipeline.java:1422) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultChannelPipeline$HeadContext.channelReadComplete(DefaultChannelPipeline.java:1417) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeChannelReadComplete(AbstractChannelHandlerContext.java:482) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeChannelReadComplete(AbstractChannelHandlerContext.java:463) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultChannelPipeline.fireChannelReadComplete(DefaultChannelPipeline.java:925) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.local.LocalChannel.readInbound(LocalChannel.java:302) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.local.LocalChannel.doBeginRead(LocalChannel.java:322) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannel$AbstractUnsafe.beginRead(AbstractChannel.java:834) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultChannelPipeline$HeadContext.read(DefaultChannelPipeline.java:1362) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeRead(AbstractChannelHandlerContext.java:835) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.read(AbstractChannelHandlerContext.java:814) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.handler.flow.FlowControlHandler.read(FlowControlHandler.java:144) ~[netty-handler-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeRead(AbstractChannelHandlerContext.java:837) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.read(AbstractChannelHandlerContext.java:814) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultChannelPipeline.read(DefaultChannelPipeline.java:1004) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannel.read(AbstractChannel.java:290) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultChannelPipeline$HeadContext.readIfIsAutoRead(DefaultChannelPipeline.java:1422) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultChannelPipeline$HeadContext.channelReadComplete(DefaultChannelPipeline.java:1417) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeChannelReadComplete(AbstractChannelHandlerContext.java:482) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.AbstractChannelHandlerContext.invokeChannelReadComplete(AbstractChannelHandlerContext.java:463) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultChannelPipeline.fireChannelReadComplete(DefaultChannelPipeline.java:925) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.local.LocalChannel.readInbound(LocalChannel.java:302) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.local.LocalChannel.access$000(LocalChannel.java:50) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.channel.local.LocalChannel$1.run(LocalChannel.java:68) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:174) ~[netty-common-4.1.97.Final.jar:?]
	at knot/io.netty.channel.DefaultEventLoop.run(DefaultEventLoop.java:54) ~[netty-transport-4.1.97.Final.jar:?]
	at knot/io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997) ~[netty-common-4.1.97.Final.jar:?]
	at knot/io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-common-4.1.97.Final.jar:?]
	at java.base/java.lang.Thread.run(Thread.java:1583) [?:?]
Caused by: io.netty.handler.codec.DecoderException: Failed to decode packet 'clientbound/minecraft:set_equipment'
	at knot/net.minecraft.class_9136.method_56425(class_9136.java:38) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_9136.decode(class_9136.java:14) ~[client-intermediary.jar:?]
	at knot/qouteall.imm_ptl.core.network.PacketRedirection$Payload.read(PacketRedirection.java:272) ~[immersive-portals-6.0.6-mc1.21.1-fabric.jar:?]
	at knot/net.minecraft.class_9139$1.decode(class_9139.java:20) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_8710$1.method_56488(class_8710.java:63) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_8710$1.decode(class_8710.java:39) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_9139$8.decode(class_9139.java:76) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_9139$9.method_56441(class_9139.java:91) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_9139$9.decode(class_9139.java:87) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_9136.method_56425(class_9136.java:36) ~[client-intermediary.jar:?]
	... 73 more
Caused by: java.lang.IndexOutOfBoundsException: readerIndex(8) + length(1) exceeds writerIndex(8): PooledUnsafeHeapByteBuf(ridx: 8, widx: 8, cap: 256)
	at knot/io.netty.buffer.AbstractByteBuf.checkReadableBytes0(AbstractByteBuf.java:1442) ~[netty-buffer-4.1.97.Final.jar:?]
	at knot/io.netty.buffer.AbstractByteBuf.readByte(AbstractByteBuf.java:730) ~[netty-buffer-4.1.97.Final.jar:?]
	at knot/net.minecraft.class_2540.readByte(class_2540.java:1172) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_2744.<init>(class_2744.java:32) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_9139$6.decode(class_9139.java:37) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_9139$9.method_56441(class_9139.java:91) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_9139$9.decode(class_9139.java:87) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_9136.method_56425(class_9136.java:36) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_9136.decode(class_9136.java:14) ~[client-intermediary.jar:?]
	at knot/qouteall.imm_ptl.core.network.PacketRedirection$Payload.read(PacketRedirection.java:272) ~[immersive-portals-6.0.6-mc1.21.1-fabric.jar:?]
	at knot/net.minecraft.class_9139$1.decode(class_9139.java:20) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_8710$1.method_56488(class_8710.java:63) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_8710$1.decode(class_8710.java:39) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_9139$8.decode(class_9139.java:76) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_9139$9.method_56441(class_9139.java:91) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_9139$9.decode(class_9139.java:87) ~[client-intermediary.jar:?]
	at knot/net.minecraft.class_9136.method_56425(class_9136.java:36) ~[client-intermediary.jar:?]
	... 73 more
[20:46:17] [Render thread/INFO]: [ImmPtl] Client accepted position packet minecraft:overworld 3.732671897025682 -60.6 6.345960966835302
[20:46:17] [Render thread/INFO]: [ImmPtl] Client accepted position packet minecraft:overworld 3.732671897025682 -60.6 6.345960966835302
[20:46:18] [Netty Local Client IO #1/ERROR]: Negative index in crash report handler (74/78)
[20:46:18] [Netty Local Client IO #1/INFO]: (This is for debugging only. You can ignore that. Logging limit 3/5) Exception from connection: 
io.netty.channel.StacklessClosedChannelException: null
	at io.netty.channel.AbstractChannel$AbstractUnsafe.write(Object, ChannelPromise)(Unknown Source) ~[netty-transport-4.1.97.Final.jar:?]
[20:46:18] [Netty Local Client IO #1/INFO]: (This is for debugging only. You can ignore that. Logging limit 4/5) Exception from connection: 
io.netty.channel.StacklessClosedChannelException: null
	at io.netty.channel.AbstractChannel$AbstractUnsafe.write(Object, ChannelPromise)(Unknown Source) ~[netty-transport-4.1.97.Final.jar:?]
[20:46:18] [Netty Local Client IO #1/INFO]: (This is for debugging only. You can ignore that. Logging limit 5/5) Exception from connection: 
io.netty.channel.StacklessClosedChannelException: null
	at io.netty.channel.AbstractChannel$AbstractUnsafe.write(Object, ChannelPromise)(Unknown Source) ~[netty-transport-4.1.97.Final.jar:?]

Critical, potential for lost data:

• Sitting near an active portal causes the world to fail to save, hanging the server.
  • Singleplayer is likely the one prone to this.
  • Steps to reproduce:
    1. Build & light a portal.
    2. Sit in front of the portal.
    3. Find that the server is trying to save but hanging.
       • The panorama in 1.21.1 is also absent in this state.
       • Quitting the game normally is impossible in this state.

Logs:

https://mclo.gs/POwLJrc

Disclaimer:

Note: I write and maintain Polysit, but one of the issues found were critical enough to warrant bringing this to your attention as it .