[MC-163879] Dispenser plays failed sound when equipping a single mob head

The bug

Dispensers play the dispensing failed sound when they equip a mob head but it not affect wither skeleton head.

How to reproduce

Activate subtitles
Put a single wither skeleton head in a dispenser
Stand in front of the dispenser and activate it

->✔ It will play the sound when an item was successfully dispensed and show the subtitle "Dispensed item"

Put only a single mob head except wither skeleton head in the dispenser
Stand in front of the dispenser and activate it

->❌ It will play the sound when an item was not successfully dispensed and show the subtitle "Dispenser failed"

Code Analysis

Code analysis by @unknown can be found in this comment.

Linked issues

relates to 1

MC-114106 Dispenser plays failed sound when equipping a single pumpkin or skull Resolved

Comments 4

SPGoding 2019-10-17T08:59:48Z

Affects dragon_head, creeper_head, zombie_head, player_head and skeleton_skull. Does not affect wither_skeleton_skull.

SPGoding 2019-10-19T11:10:02Z

The code for Items.WITHER_SKELETON_SKULL and Blocks.CARVED_PUMPKIN in net/minecraft/core/dispenser/DispenseItemBehavior is changed from

ItemStack itemStack7 = ArmorItem.dispenseArmor(blockSource, itemStack);
if (itemStack7.isEmpty()) {
   this.success = false;
}

ItemStack itemStack7 = ArmorItem.dispenseArmor(blockSource, itemStack);
if (itemStack.getCount() < itemStack7.getCount()) {
   this.success = false;
}

to fix MC-114106 in 19w42a.

However, this is not changed for other heads/skull items.

DispenseItemBehavior dispenseItemBehavior3 = new OptionalDispenseItemBehavior() {
   @Override
   protected ItemStack execute(final BlockSource blockSource, final ItemStack itemStack) {
      this.success = !ArmorItem.dispenseArmor(blockSource, itemStack).isEmpty();
      return itemStack;
   }
};

TheBoy358 2019-11-28T20:29:00Z

Fixed in 1.15 pre3.

SPGoding 2019-12-02T17:27:21Z

Yes confirmed, fixed in 1.15-pre3.