CyclopsMC / CyclopsCore / 34099049926

27%

master-1.21: 31%

Pull #242

github

Identify inventories by instance instead of by contents

SimpleInventoryCommon compared inventories by their contents and returned a
modification counter as its hash code. Both are wrong for a mutable container,
and together they break item transfer APIs that cache their wrappers in a map
keyed on the container.

Fabric's InventoryStorage is such a cache, and uses equals-based keys:

    private static final Map<Inventory, InventoryStorageImpl> WRAPPERS = new MapMaker().weakValues().makeMap();

Two empty inventories of the same size were therefore equal and hashed the
same, so the second one looked up was handed the first one's storage. Items
inserted into one block ended up in another, and reading a block's contents
returned the other one's items. The changing hash code additionally made an
inventory lose its own cache entry after every modification.

Instances are now compared by identity. getState() still returns the
modification counter, so change detection is unaffected.

The deprecated NeoForge-only SimpleInventory keeps its contents-based equality:
it backs the cyclopscore:inventory data component, which needs value equality.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wbskd84GPZPE1rB7spHkdn

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