slot index exceeds capacity

Error message

slot index {slotIndex} exceeds capacity {self.Capacity}

What it means

Thrown by the SERVER-side ItemComponentSystem.EnsureSlotIndex when slotIndex >= self.Capacity (the second guard, after the negative check). This is the server-side twin of error 200. The server bag defaults to Capacity 100 (Awake, line 17), so any index at or above the current capacity is rejected before writing SlotItems.

Solutions

Grow Capacity via SetCapacity before placing items at higher indices.
When shrinking capacity, first move/evict items in slots >= new Capacity (the code currently never shrinks SlotItems, so a manual remap is required).
Always read self.Capacity at call time rather than caching it.

Example fix

// before
component.SetSlotItem(115, item); // Capacity still 100

// after
if (component.Capacity <= 115) component.SetCapacity(120);
component.SetSlotItem(115, item);

Defensive patterns

Strategy: validation

Validate before calling

if (slotIndex < 0 || slotIndex >= component.Capacity)
{
    Log.Error($"slot {slotIndex} invalid for capacity {component.Capacity}");
    return;
}
component.SetSlotItem(slotIndex, item);

Prevention

Grow Capacity before placing items at higher indices.
When shrinking, remap items out of the truncated range first.
Read self.Capacity live; do not trust a stale cached value.

When it happens

Trigger: Server code calls SetSlotItem with an index that was valid under a larger capacity but the bag was shrunk, or a caller computed an index from a stale/config capacity that exceeds the live Capacity. Also triggered if SetCapacity is never called to grow the bag before placing items beyond the default 100.

Common situations: Capacity shrink without re-mapping existing items; a config change lowering the bag size while items still occupy high slots; server logic that assumes a bigger bag than was actually allocated.

Related errors

AI-assisted analysis of egametang/ET@5cab01f7a8 (2026-08-13). Data as JSON: /api/errors/7568b24089cf46ea. Report an issue: GitHub.

Appendix: source

Thrown at Packages/cn.etetet.item/Scripts/Hotfix/Server/ItemComponentSystem.cs:205

        {
            if ((uint)slotIndex < (uint)self.SlotItems.Count)
            {
                return self.SlotItems[slotIndex];
            }

            return null;
        }

        private static void EnsureSlotIndex(ItemComponent self, int slotIndex)
        {
            if (slotIndex < 0)
            {
                throw new Exception($"invalid slot index: {slotIndex}");
            }

            if (slotIndex >= self.Capacity)
            {
                throw new Exception($"slot index {slotIndex} exceeds capacity {self.Capacity}");
            }
        }

        private static void EnsureSlotContainerSize(ItemComponent self, int size)
        {
            if (size <= 0)
            {
                return;
            }

            if (self.SlotItems.Count >= size)
            {
                return;
            }

            int addCount = size - self.SlotItems.Count;
            for (int i = 0; i < addCount; ++i)
            {

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