[SOLVED] [1.12] NoSuchMethodError for getSlotFor

[IceMetalPunk]

After testing my Totem Essentials mod and having no issues, I released it, but now I'm getting a report from someone that they're getting crashes. This is the log they submitted: https://gist.github.com/knoxhack/4ae7603dfa1d9e33e35f363000e6faa4

 

As you can see, it's caused by a NoSuchMethodError for net.minecraft.entity.player.InventoryPlayer.func_184429_b, which is the SRG name for InventoryPlayer#getSlotFor(), which simply takes an ItemStack and finds the slot that matches it in the player's inventory.

What would cause that method to not exist, especially when I never got this crash in my own Minecraft environment? I'm guessing it's some sort of mod conflict with one of the mods Knoxhack has installed, but what kind of mod conflict can remove the existence of a core method like that?

Edited October 28, 2017 by IceMetalPunk

[tebreca]

7 minutes ago, IceMetalPunk said:

After testing my Totem Essentials mod and having no issues, I released it, but now I'm getting a report from someone that they're getting crashes. This is the log they submitted: https://gist.github.com/knoxhack/4ae7603dfa1d9e33e35f363000e6faa4

 

As you can see, it's caused by a NoSuchMethodError for net.minecraft.entity.player.InventoryPlayer.func_184429_b, which is the SRG name for InventoryPlayer#getSlotFor(), which simply takes an ItemStack and finds the slot that matches it in the player's inventory.

What would cause that method to not exist, especially when I never got this crash in my own Minecraft environment? I'm guessing it's some sort of mod conflict with one of the mods Knoxhack has installed, but what kind of mod conflict can remove the existence of a core method like that?

Did you try to run the func on the server side only??

Edited October 24, 2017 by tebreca

[tebreca]

3 minutes ago, tebreca said:

Did you try to run the func on the server side only??

it says

	at net.minecraft.world.World.func_72939_s(World.java:1755)
	at net.minecraft.world.WorldServer.func_72939_s(WorldServer.java:612)

 maybe you need to do a !World.isRemote statement

[Draco18s]

>> No code posted

> Help not available

[IceMetalPunk]

On 10/24/2017 at 10:02 AM, tebreca said:

it says

	at net.minecraft.world.World.func_72939_s(World.java:1755)
	at net.minecraft.world.WorldServer.func_72939_s(WorldServer.java:612)

 maybe you need to do a !World.isRemote statement

I mean... if that was the issue, wouldn't I have also gotten the error when testing? Besides, World#isRemote returns true if it's on the client, meaning if I check for !isRemote, my code will only run on the server... and as you pointed out, this error is triggering on the server... Normally, I'd be willing to at least try it, but since I can't replicate the error, the only way to see if my patch works is by re-releasing a revision and waiting for the players to try again. I don't want to keep releasing revisions unless I at least know I'm going in the right direction with the bugfixes.

On 10/24/2017 at 11:19 AM, Draco18s said:

>> No code posted

> Help not available

I didn't think my code was pertinent since the error is that a vanilla method isn't found... the TEEvents class has a *lot* of code in it (and most is probably completely unrelated to this bug), so I don't want to post the entire class...

Here's the TEEvents#getStackInPlayerInv method that's calling the getSlotFor method:

	// Helper method to get a matching stack from a player's inventory,
	// regardless of which part of the inventory it's in.
	public static ItemStack getStackInPlayerInv(EntityPlayer player, ItemStack compareTo) {
		InventoryPlayer inv = player.inventory;
		ItemStack stack = ItemStack.EMPTY;
		int slotID = inv.getSlotFor(compareTo); // Doesn't include offhand!
		if (slotID < 0) {
			ItemStack inOffhand = player.getHeldItemOffhand();
			if (inOffhand.getItem() == compareTo.getItem()
					&& (!inOffhand.getHasSubtypes() || inOffhand.getMetadata() == compareTo.getMetadata())
					&& ItemStack.areItemStackTagsEqual(inOffhand, compareTo)) {
				stack = inOffhand;
			} else {
				for (ItemStack armorStack : player.getArmorInventoryList()) {
					if (armorStack.getItem() == compareTo.getItem()
							&& (!armorStack.getHasSubtypes() || armorStack.getMetadata() == compareTo.getMetadata())
							&& ItemStack.areItemStackTagsEqual(armorStack, compareTo)) {
						stack = armorStack;
						break;
					}
				}
			}
		} else {
			stack = inv.getStackInSlot(slotID);
		}
		return stack;
	}

And the TEEnsouledEvents#onAttackTarget method which is calling that:

	@SubscribeEvent
	public void onAttackTarget(LivingSetAttackTargetEvent ev) {
		EntityLivingBase target = ev.getTarget();
		if (target instanceof EntityPlayer) {
			ItemStack stack = TEEvents.getStackInPlayerInv((EntityPlayer) target,
					new ItemStack(TotemEssentials.proxy.items.get("ensouled_aggression_totem")));
			if (stack != ItemStack.EMPTY) {
				ItemEnsouledAggressionTotem.performEffect(stack, ev.getEntity().world, (EntityPlayer) target);
			}
		}
	}

 

And as the stacktrace shows, everything leading up to that is Forge/vanilla code, so those should be the only relevant bits of my code.

[Choonster]

InventoryPlayer#getSlotFor is a client-only method (i.e. it's annotated with @SideOnly(Side.CLIENT)), so it doesn't exist on the dedicated server and can't be used from common code (like an event handler running on the logical server).

[IceMetalPunk]

3 minutes ago, Choonster said:

InventoryPlayer#getSlotFor is a client-only method (i.e. it's annotated with @SideOnly(Side.CLIENT)), so it doesn't exist on the dedicated server and can't be used from common code (like an event handler running on the logical server).

Wait... I may have misunderstood. When you say "dedicated server", that includes the integrated single-player server, too, right? If that's the case, wouldn't I have gotten this crash during my testing (which, by the way, properly called ItemEnsouledAggressionTotem.performEffect())? Or do you mean the method exists on both the client and the integrated server, but not on a standalone server?

If the latter is the case, how would I go about getting a match on an item stack anywhere in the player's inventory? Do I need to iterate over the entire inventory myself?

[jabelar]

The reason you missed it when you were testing is because you probably tested in single player mode. You MUST test your mods by running a separate server and client. Within Eclipse you can simply run both the client and server configurations at same time and connect to the local host 127.0.0.1.

 

This happens because when running in single player there is only one Java VM running both sides to it actually sees the classes that are loaded on the other sides. But if you run a dedicated server run configuration you will have two separate Java VMs each loading only their own classes.

 

The isRemote is for an entirely different thing. This problem is related to classes and how they are loaded, not just how they are executed.

[IceMetalPunk]

1 minute ago, jabelar said:

The reason you missed it when you were testing is because you probably tested in single player mode. You MUST test your mods by running a separate server and client. Within Eclipse you can simply run both the client and server configurations at same time and connect to the local host 127.0.0.1.

 

This happens because when running in single player there is only one Java VM running both sides to it actually sees the classes that are loaded on the other sides. But if you run a dedicated server run configuration you will have two separate Java VMs each loading only their own classes.

 

The isRemote is for an entirely different thing. This problem is related to classes and how they are loaded, not just how they are executed.

Ahhh.... suddenly things make sense. I was under the impression that the integrated server was essentially identical, for the most part, to the dedicated server. Clearly, I was mistaken.

So now I'm just left with that final question: is there an easier way to get an item stack from the player's inventory that matches a given stack loosely, without iterating over everything myself? (From the server-side, of course.)

[Choonster]

16 minutes ago, IceMetalPunk said:

Wait... I may have misunderstood. When you say "dedicated server", that includes the integrated single-player server, too, right? If that's the case, wouldn't I have gotten this crash during my testing (which, by the way, properly called ItemEnsouledAggressionTotem.performEffect())? Or do you mean the method exists on both the client and the integrated server, but not on a standalone server?

@SideOnly restricts classes, methods and fields to a specific physical side. The integrated server runs on the physical client, so it has access to things annotated with @SideOnly(Side.CLIENT) (though it should never actually use these). The dedicated server runs on the physical server, which doesn't have access to things annotated with @SideOnly(Side.CLIENT).

 

Quote

If the latter is the case, how would I go about getting a match on an item stack anywhere in the player's inventory? Do I need to iterate over the entire inventory myself?

Use InventoryPlayer#hasItemStack to check if an ItemStack is anywhere in a player's inventory, matching the Item and metadata but not the NBT or capabilities.

Edited October 26, 2017 by Choonster

[IceMetalPunk]

2 minutes ago, Choonster said:

@SideOnly restricts classes, methods and fields to a specific physical side. The integrated server runs on the physical client, so it has access to things annotated with @SideOnly(Side.CLIENT) (though it should never actually use these). The dedicated server runs on the physical server, which doesn't have access to things annotated with @SideOnly(Side.CLIENT).

 

Use InventoryPlayer#hasItemStack to check if an ItemStack is anywhere in a player's inventory, matching the Item and metadata but not the NBT or capabilities.

Thank you for the clarification!

So the problem with hasItemStack is that it matches metadata/damage, and I need to check if the item is in the inventory regardless of its damage value. That's why I ended up writing that little static helper method. The getSlotFor method uses stackEqualExact, which checks the hasSubtypes field before deciding whether to compare damage values or not.

So it looks like I'm going to have to basically rewrite getSlotFor()'s loop in my own code? I mean, it's not terrible, it just feels like this is a functionality that would already exist somewhere in MC's or Forge's code base...

[IceMetalPunk]

Thanks, guys; I implemented my own iteration and got this working. I still feel like there should be some sort of metadata-insensitive item search method available to both client and server... but whatever, it works