The bug

The durability bar used by damageable items can appear completely empty even in cases where it has remaining uses.

I consider this to be an issue for much the same reason as MC-120664 was fixed: empty durability should imply the tool is no longer usable at all, rather than having a tiny pool of residual uses.

How to reproduce

Have an item, preferably one with high base durability, that is a small matter of uses (greater than one) from breaking.

Expected results

As the item can still be used, the durability bar should appear at its lowest level, but not empty (i.e. one red pixel). Empty durability bars should only be used if the durability is 0 or a negative number.

Actual results

The tool can still be used even when the durability bar looks empty, even though this logically doesn't make much sense.

Code analysis

Code analysis by LegoEmmetMC can be found in this comment.