Accounting for Slot stack limit in Container.mergeItemStack()

[Eastonium]

I recently added a slot to a container I had, and overrided the getSlotStackLimit() function.

However, when I shift-clicked items from my inventory, the value I set in getSlotStackLimit() was completely ignored.

 

I ended up having to override the mergeItemStack() function in my container class to account for the slot stack limit.

I think this would be a good thing to change for all instances however, and given forge already changes the mergeItemStack() function to make sure that the item (to put in) is valid for the slot, I don't see why this shouldn't be added.

 

Here's the new version of the function that I came up with:

//Changed to be sensitive to Slot stack limits
@Override
protected boolean mergeItemStack(ItemStack stack, int startIndex, int endIndex, boolean reverseDirection){
    boolean flag = false;
    int i = startIndex;
    if (reverseDirection) i = endIndex - 1;
    
    if (stack.isStackable()){
        while (stack.stackSize > 0 && (!reverseDirection && i < endIndex || reverseDirection && i >= startIndex)){
            Slot slot = (Slot)this.inventorySlots.get(i);
            ItemStack itemstack = slot.getStack();
            int maxLimit = Math.min(stack.getMaxStackSize(), slot.getSlotStackLimit());
            
            if (itemstack != null && areItemStacksEqual(stack, itemstack)){
                int j = itemstack.stackSize + stack.stackSize;
                if (j <= maxLimit){
                    stack.stackSize = 0;
                    itemstack.stackSize = j;
                    slot.onSlotChanged();
                    flag = true;
                    
                }else if (itemstack.stackSize < maxLimit){
                    stack.stackSize -= maxLimit - itemstack.stackSize;
                    itemstack.stackSize = maxLimit;
                    slot.onSlotChanged();
                    flag = true;
                }
            }
            if (reverseDirection){ 
            	--i;
            }else ++i;
        }
    }
    if (stack.stackSize > 0){
        if (reverseDirection){
            i = endIndex - 1;
        }else i = startIndex;

        while (!reverseDirection && i < endIndex || reverseDirection && i >= startIndex){
            Slot slot1 = (Slot)this.inventorySlots.get(i);
            ItemStack itemstack1 = slot1.getStack();

            if (itemstack1 == null && slot1.isItemValid(stack)){ // Forge: Make sure to respect isItemValid in the slot.
            	if(stack.stackSize <= slot1.getSlotStackLimit()){
            	    slot1.putStack(stack.copy());
                    slot1.onSlotChanged();
                    stack.stackSize = 0;
                    flag = true;
                    break;
            	}else{
            	    itemstack1 = stack.copy();
            	    stack.stackSize -= slot1.getSlotStackLimit();
                    itemstack1.stackSize = slot1.getSlotStackLimit();
                    slot1.putStack(itemstack1);
                    slot1.onSlotChanged();
                    flag = true;
            	}                    
            }
            if (reverseDirection){
                --i;
            }else ++i;
        }
    }
    return flag;
}

I'm not currently using 4 spaces or the other formatting stuff, but I can change that if need be.

[Draco18s]

This would be really nice.  I was able to work around the issue in 1.7, as things generally accounted for it except in the TransferStack method, which everyone always supplied a copy-paste from the wiki because It Worked.

 

Now though, I can't.  Even the method above isn't sufficient to fix the issues I have trying to make a hopper with a slot stack limit of 16.

 

One problem is that shift-clicking results in an infinite loop:

at net.minecraft.inventory.Container.retrySlotClick(Container.java:549)

at net.minecraft.inventory.Container.slotClick(Container.java:284)

at net.minecraft.inventory.Container.retrySlotClick(Container.java:549)

at net.minecraft.inventory.Container.slotClick(Container.java:284)

 

"If I failed, retry with the same parameters, maybe it'll work then."  Yeesh.

 

The other is that hopper also doesn't respect is own inventory limits when pulling from other containers.  It pulls the item, puts it into its inventory, then checks the stack against the size limits and deletes the extra.

 

"Click, click" works properly (only 16 are put into the slot) as does hopper-push.

But shift-clicking and hopper-pull is broken.

 

:\

[Eastonium]

Finally, someone replied!

 

When are you getting the infinite loop? (hopper-pull, shift-click...)

Also, I made my modifications to the mergeItemStack() function when I came across problems while shift-clicking, and I tested it and it worked fine for me. How is shift-clicking not working for you?

 

I'm determined to get this added to forge (hopefully) now that I know others wish this were a thing.

 

[Draco18s]

When are you getting the infinite loop? (hopper-pull, shift-click...)

 

Shift-click.