Submission Details
Severity:
mintEgg return value consumes gas
Summary
The EggstravaganzaNFT.mintEgg(address,uint256) function returns an unneeded value, using extra gas.
Vulnerability Details
The following code returns a boolean value:
function mintEgg(address to, uint256 tokenId) external returns (bool) {
require(msg.sender == gameContract, "Unauthorized minter");
_mint(to, tokenId);
totalSupply += 1;
return true;
}
This value is only used in a test. The function can never return false and is not needed to test that the function actually works.
Example of test with return value:
Traces:
[140937] EggGameTest::testMintEgg()
├─ [0] VM::prank(EggHuntGame: [0xF62849F9A0B5Bf2913b396098F7c7019b51A820a])
│ └─ ← [Return]
├─ [93603] EggstravaganzaNFT::mintEgg(ECRecover: [0x0000000000000000000000000000000000000001], 1)
│ ├─ emit Transfer(from: 0x0000000000000000000000000000000000000000, to: ECRecover: [0x0000000000000000000000000000000000000001], tokenId: 1)
│ └─ ← [Return] true
The same test without the return value
Traces:
[139871] EggGameTest::testMintEgg()
├─ [0] VM::prank(EggHuntGame: [0xF62849F9A0B5Bf2913b396098F7c7019b51A820a])
│ └─ ← [Return]
├─ [93405] EggstravaganzaNFT::mintEgg(ECRecover: [0x0000000000000000000000000000000000000001], 1)
│ ├─ emit Transfer(from: 0x0000000000000000000000000000000000000000, to: ECRecover: [0x0000000000000000000000000000000000000001], tokenId: 1)
│ └─ ← [Stop]
Impact
The return value wastes 198 gas per minted egg
Tools Used
Manual review
Recommendations
Remove return value from
mintEggAdjust test to remove
assertTrue(success);
Updates
Lead Judging Commences
m3dython 3 months ago
Submission Judgement Published Reason: Non-acceptable severity
Assigned finding tags:
Gas optimization
Strategy to save gas and minimize transaction costs
Rewards breakdown
nSLOC
129This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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