So all you have to do is:
1. Get something that takes durability damage when using it.
2. Using NBTEdit or MCedit change the damage value to -30000 (Or a little less)
3. Use it in-game and it does not keep the damage you set on it.
What I did:
I was wanting to change the durability on items so I went into MCEdit and changed the durability on a bow to be -30000 so it wouldn't break for a while. When I finished, I shot the bow, but it took damage. This should not have happened.
Linked issues
is duplicated by 5
MC-10675
When editing the damage in MCEdit, when the item is taken out of the chest or dispenser, the damage resets to 0.
Resolved
MC-11956
Unbreakable Items Not Working. Example: /give CaptainDuude 276 1 -15536 | That used to give you a diamond sword with a huge durability but now it doesn't.
Resolved
MC-12149
Unbreakable Tools no longer available.
Resolved
MC-12186
Negative Damage Values not applying
Resolved
MC-12318
wen i use /give name thing 64 -30000 i dont get the allmoste forever durability, i get the normal durability. and things that had allmoste forever durability lost it!
Resolved
Negative damage values were fixed, see MC-10112.