Submission Details
Severity:
[L-2] The length member of the storage array `players` is being referenced instead of using cached array length in `ThePredicter::withdraw` function
Summary: Many places in the code during comparison in the loop, the players.length variable is reference instead of using a local variable to cache the length of the array `players`.
Vulnerability Details: In the below code in the ThePredicter::withdraw function, the `players.length` is being used which will cost more gas. It is also used at other places like ThePredicter::withdrawPredictionFees function.
function withdraw() public {
if (!scoreBoard.isEligibleForReward(msg.sender)) {
revert ThePredicter__NotEligibleForWithdraw();
}
-
int8 score = scoreBoard.getPlayerScore(msg.sender);
int8 maxScore = -1;
int256 totalPositivePoints = 0;
for (uint256 i = 0; i < players.length; ++i) {
int8 cScore = scoreBoard.getPlayerScore(players[i]);
if (cScore > maxScore) maxScore = cScore;
if (cScore > 0) totalPositivePoints += cScore;
}
uint256 fees = address(this).balance - players.length * entranceFee;
Impact: This is costing more gas. As there is no modification in the length of array. Hence, a local variable could be used to make it more gas efficient.
Tools Used: Slither and VScode.
Recommendations: A local variable `length` is created and assigned to the `players.length`.
uint256 private _length = players.length;
function withdraw() public lock {
if (!scoreBoard.isEligibleForReward(msg.sender)) {
revert ThePredicter__NotEligibleForWithdraw();
}
int8 score = scoreBoard.getPlayerScore(msg.sender);
int8 maxScore = -1;
int256 totalPositivePoints = 0;
int8[] memory playerScores = new int8[](_length);
for (uint256 i = 0; i < _length; ++i) {
playerScores[i] = scoreBoard.getPlayerScore(players[i]);
}
for (uin t256 i = 0; i < _length; ++i) {
int8 cScore = playerScores[i];
if (cScore > maxScore) maxScore = cScore;
if (cScore > 0) totalPositivePoints += cScore;
}
Rewards breakdown
nSLOC
191This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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