Rule 614.7 · Replacement Effects
If a replacement effect would replace an event, but that event never happens, the replacement effect simply doesn’t do anything.
Subrules
If a source would deal 0 damage, it does not deal damage at all. Replacement effects that would increase the damage dealt by that source, or would have that source deal that damage to a different object or player, have no event to replace, so they have no effect.