Adding a new slot to container returns an IndexOutOfBounds exception

[Insane96MCP]

I'm trying to copy the anvil container. But as soon as I try to make 

this.addSlotToContainer(new Slot(...));

and I open the GUI, I get a java.lang.IndexOutOfBoundsException: Index: 39, Size: 39:

[11:27:18] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.IndexOutOfBoundsException: Index: 39, Size: 39
	at java.util.concurrent.FutureTask.report(Unknown Source) ~[?:1.8.0_141]
	at java.util.concurrent.FutureTask.get(Unknown Source) ~[?:1.8.0_141]
	at net.minecraft.util.Util.runTask(Util.java:30) [Util.class:?]
	at net.minecraft.client.Minecraft.runGameLoop(Minecraft.java:1109) [Minecraft.class:?]
	at net.minecraft.client.Minecraft.run(Minecraft.java:407) [Minecraft.class:?]
	at net.minecraft.client.main.Main.main(Main.java:118) [Main.class:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_141]
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_141]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_141]
	at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_141]
	at net.minecraft.launchwrapper.Launch.launch(Launch.java:135) [launchwrapper-1.12.jar:?]
	at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_141]
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_141]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_141]
	at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_141]
	at net.minecraftforge.gradle.GradleStartCommon.launch(GradleStartCommon.java:97) [start/:?]
	at GradleStart.main(GradleStart.java:26) [start/:?]
Caused by: java.lang.IndexOutOfBoundsException: Index: 39, Size: 39
	at java.util.ArrayList.rangeCheck(Unknown Source) ~[?:1.8.0_141]
	at java.util.ArrayList.get(Unknown Source) ~[?:1.8.0_141]
	at net.minecraft.inventory.Container.getSlot(Container.java:135) ~[Container.class:?]
	at net.minecraft.inventory.Container.setAll(Container.java:554) ~[Container.class:?]
	at net.minecraft.client.network.NetHandlerPlayClient.handleWindowItems(NetHandlerPlayClient.java:1306) ~[NetHandlerPlayClient.class:?]
	at net.minecraft.network.play.server.SPacketWindowItems.processPacket(SPacketWindowItems.java:72) ~[SPacketWindowItems.class:?]
	at net.minecraft.network.play.server.SPacketWindowItems.processPacket(SPacketWindowItems.java:13) ~[SPacketWindowItems.class:?]
	at net.minecraft.network.PacketThreadUtil$1.run(PacketThreadUtil.java:21) ~[PacketThreadUtil$1.class:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.8.0_141]
	at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.8.0_141]
	at net.minecraft.util.Util.runTask(Util.java:29) ~[Util.class:?]
	... 15 more

 

Here's the code

Another problem is that seems like the server is not getting input properly so I can't output nothing from the anvil. But I think that fixing the excpetion will solve this too.

 

 

Edited September 29, 2017 by Insane96MCP

[jeffryfisher]

When you stepped into and through

this.addSlotToContainer(new Slot(...));

  in the debugger, did you see the array being extended?

[Insane96MCP]

11 hours ago, jeffryfisher said:

When you stepped into and through

this.addSlotToContainer(new Slot(...));

  in the debugger, did you see the array being extended?

Nope, no exception is given going through addSlotToContainer in the debugger . It happens later

Edited September 30, 2017 by Insane96MCP

[jeffryfisher]

Well then, if the array isn't getting bigger, but you try to access more elements than were allocated, then you're going to run off the end. Fix it.

[Insane96MCP]

On 2/10/2017 at 8:13 PM, jeffryfisher said:

Well then, if the array isn't getting bigger, but you try to access more elements than were allocated, then you're going to run off the end. Fix it.

The problem is that I'm using a vanilla method, and it should work alone.

[Choonster]

You're using Containers with a different number of Slots on the client and server. The client uses ContainerRepair; but the server uses GuiServer, which extends ContainerRepair and adds an extra Slot. The client-side Container doesn't have a Slot at this index, so the update packets throw an IndexOutOfBoundsException.

 

You need to use Containers with the same number of slots on both sides, usually instances of the same class. GuiRepair doesn't have a constructor that lets you provide your own Container, so you'll probably need to copy rather than extend it.

 

If you extend a class, you don't need to copy all of its fields and methods; you only need to override the methods that should have different behaviour. To access the private IInventory fields in ContainerRepair, either use reflection or get the corresponding Slots from Container#inventorySlots and get the inventory from the Slot#inventory field.

 

GuiServer isn't a good name, since it's not a GUI and the server doesn't have GUIs. I recommend following the MCP naming conventions and naming it something like ContainerGoldenAnvil.