Omniscia Gnosis Guild Audit
Consumptions Code Style Findings
Consumptions Code Style Findings
CSN-01C: Inefficient Lookup Operation of Consumptions
| Type | Severity | Location |
|---|---|---|
| Gas Optimization |  | Consumptions.sol:L64 |
Description:
The Consumptions::find function that is invoked within Consumptions::merge is invoked so with a result array that contains multiple zeroed out entries that are iterated redundantly.
Example:
packages/evm/contracts/Consumptions.sol
46function merge(47 Consumption[] memory c1,48 Consumption[] memory c249) internal pure returns (Consumption[] memory result) {50 if (c1.length == 0) return c2;51 if (c2.length == 0) return c1;52
53 result = new Consumption[](c1.length + c2.length);54
55 uint256 length = c1.length;56 unchecked {57 for (uint256 i; i < length; ++i) {58 result[i].allowanceKey = c1[i].allowanceKey;59 result[i].balance = c1[i].balance;60 result[i].consumed = c1[i].consumed;61 }62
63 for (uint256 i; i < c2.length; ++i) {64 (uint256 index, bool found) = find(result, c2[i].allowanceKey);65 if (found) {66 result[index].consumed += c2[i].consumed;67 } else {68 result[length].allowanceKey = c2[i].allowanceKey;69 result[length].balance = c2[i].balance;70 result[length].consumed = c2[i].consumed;71 length++;72 }73 }74 }Recommendation:
As the result array contains all c1 elements at the same indexes, the Consumptions::find function could accept the c1 array as an input and use the same index to operate on the result array.
To note, the contract itself assumes that consumptions do not contain duplicate allowanceKey entries by themselves rendering this approach possible.
Alleviation:
The input of the referenced Consumptions::find function invocation statement has been adjusted to the c1 array as advised, optimizing the lookup operation significantly and thus alleviating this exhibit.