The bug

When a villager wants to buy a tool, it will look for a Damage:0 tag while it should be ignored. Normally obtained tools do not have Damage ever set to 0 (until after a reload – more information in MC-125880).

Steps to reproduce

1. Summon a villager which asks for a diamond pickaxe:

   /summon villager ~ ~ ~ {Offers:{Recipes:[{uses:0,maxUses:1,buy:{id:diamond_pickaxe,Count:1},sell:{id:emerald,Count:1}}]}}

2. Get a diamond pickaxe via crafting or the creative inventory
3. Try to trade
   → It won’t work
4. Get a diamond pickaxe via

   /give @s diamond_pickaxe{Damage:0}
   

5. Try to trade
   → It works