Slots with item outline textures behave inconsistently when items are placed inside of these slots

The bug

Some block and entity inventory slots contain item outline textures overlaid on top of the slot to indicate what they accept. When an item is placed into these slots, the game does not behave consistently with respect to if the outline disappears or not.

Prior to 23w31a, these cases were covered in MC-74408. However, that ticket now only covers brewing stands, even though the issue persists for other slot types.

How to reproduce

A resource pack is attached to this ticket which replaces several item textures and models with small squares, allowing the outline to still be seen if it is not hidden if an item is added to a slot.

Table of slots

The following are all of these outline-using slots as well as how they behave when an item is added. The expected behaviour is that the outline would disappear when an item is placed within, which does not always happen.

How to fix

Fixing MC-74408 would likely fix the brewing stand case. For the horse and llama cases, the normal "slot" texture would need to be used, with the "armor slot"/"saddle slot" texture overlaid on top, like is the case with most other slots.

Further notes

On a tangientally related note, it may also be worth moving all of the slot outline textures from the "items" directory to the "gui" directory since they're GUI related. Loom, horse and llama slot textures are already under "gui", so no change is needed here. The following textures would be moved and possibly renamed:

• item/empty_armor_slot_boots.png
• item/empty_armor_slot_chestplate.png
• item/empty_armor_slot_helmet.png
• item/empty_armor_slot_leggings.png
• item/empty_armor_slot_shield.png
• item/empty_slot_amethyst_shard.png
• item/empty_slot_axe.png
• item/empty_slot_diamond.png
• item/empty_slot_emerald.png
• item/empty_slot_hoe.png
• item/empty_slot_ingot.png
• item/empty_slot_lapis_lazuli.png
• item/empty_slot_pickaxe.png
• item/empty_slot_quartz.png
• item/empty_slot_redstone_dust.png
• item/empty_slot_shovel.png
• item/empty_slot_smithing_template_armor_trim.png
• item/empty_slot_smithing_template_netherite_upgrade.png
• item/empty_slot_sword.png