Command to reproduce:
/give @a minecraft:tipped_arrow 1 0 {Potion:"minecraft:weakness"}/give @a minecraft:tipped_arrow 1 0 {Potion:"minecraft:weakness"}
MC-87150
Weakness Arrow makes you unablet to do damage generally
Resolved
Cannot Reproduce
0
Cannot confirm for 15w42a the only reduce the damage you deal. So you cannot deal damage with your hand or any weapon that deals <= 4 attack damage