Iron Backpacks (Unofficial Port)

Iron Backpacks 1.0.3 for Minecraft 1.21.1, NeoForge and Fabric (Java 21): fixes of bugs the original mod had. An unofficial port of Iron Backpacks 3.0.8 by gr8pefish (GPL-3.0).

Install: drop the jar for your loader into the mods folder of the server and of every client; JEI is optional.

Fixes of the original mod's bugs

• No more item duplication through an open backpack (original issues #234, #268). The backpack GUI stayed open after its backpack was dropped (for example the drop key pressed together with the open key) or pulled out by another mod, so its slots could be emptied while the dropped backpack still held the items. Now the GUI closes as soon as that backpack leaves the player, and clicks after that do nothing.
• Contents are no longer lost or reverted by inventory sorters (#255, #221). The contents were written only when the GUI closed, into the backpack that was opened; a sorter that moved or replaced it while the GUI was open left the new copy with the old contents. Every change is now saved into the backpack at once.
• The open key respects the Latch upgrade. It opened anyone's latched backpack in your inventory (only a right click checked the owner).
• The open key plays the opening sound (#243).

Tested

• 20 in-game tests (GameTests) on NeoForge 21.1.256 and on Fabric (Fabric API 0.116.17), also with the Fabric release jar on a real Fabric server.
• The scripted client scene on both loaders: every backpack, its GUI, dyed backpacks, tooltips, the anvil, the creative tab and JEI 19.57 (NeoForge) / 19.56 (Fabric).

Known issues: none new.

Report bugs of this port here, not to the original author. Every difference from 1.12.2: PORTLOG.md.