When hitting a pig (for example), the damage done will be 2 points (one heart). However, when you use a wooden shovel with +1 damage, the damage done is the same as you would have done without having anything in hand. When trying to use another tool or weapon, the final damage will be the added damage of the weapon plus one, implying that the fist damage should be one.

Steps to Reproduce:

• Spawn a pig and put a saddle on it.
• Use your fist to deal damage to the pig and mount it to see the damage done. (1) 
• Use a wooden shovel to deal damage to the pig and then mount it to see the damage done. (2)
• Use a stone shovel to deal damage to the pig and ride it to see the damage done. (3)

Observed Results:

(1) Fist damage is 2 points (one heart).

(2) The damage done is 2 points (one heart less).

(3) The damage caused is 3 points (one and a half hearts less).

Expected Results:

(1) Fist damage should be one point (due to what comes in the following points).

(2) The damage is correct, but, being two points and having the +1 damage tool, it implies that the damage you would do without the +1 of the tool would be one (half a heart).

(3) The damage done is still correct. However, it proves once again that weapon / tool damage is always added to one point of damage, ergo, the damage you should do if you didn't use that weapon / tool would be one point (half a heart).