Summary

defenderBet and defenderTokenId are not reset with defender is reset.

Vulnerability Details

When a battle takes place, the defender is reset to 0 address, regardless of who wins. However, the defenderBet and defenderToken are not reset, causing a discrepancy between the contracts intended state and its actual state.

Impact

This vulnerability could confuse users who relied on checking defenderBet or defenderToken to see if there was a defender rather then defender.
For example, a defender has a advantage over a attacker due to if (random <= defenderRapperSkill) {, the addition of the equals gives a point advantage. So a user is encouraged to be a defender, if they where to check whether a defender was present based on defenderBet, they may never see the opportunity to become the defender.

Tools Used

Manual review

Recommendations

Add resets for defenderBet and defenderToken to RapBattle:_battle().