Platform: Code4rena
Start Date: 14/07/2022
Pot Size: $25,000 USDC
Total HM: 2
Participants: 63
Period: 3 days
Judge: PierrickGT
Total Solo HM: 1
Id: 147
League: ETH
Rank: 59/63
Findings: 1
Award: $16.88
🌟 Selected for report: 0
🚀 Solo Findings: 0
🌟 Selected for report: IllIllI
Also found by: 0x1f8b, 0x29A, 0xKitsune, 0xNazgul, Aymen0909, Chom, Deivitto, ElKu, JC, JohnSmith, Kaiziron, Limbooo, MadWookie, Meera, ReyAdmirado, Rohan16, Sm4rty, SooYa, TomJ, Trumpero, Waze, __141345__, ajtra, ak1, antonttc, bulej93, c3phas, cRat1st0s, csanuragjain, defsec, durianSausage, fatherOfBlocks, gogo, hake, hickuphh3, ignacio, joestakey, karanctf, kyteg, m_Rassska, pashov, rajatbeladiya, rbserver, robee, rokinot, samruna, sashik_eth, simon135, tofunmi
16.8778 USDC - $16.88
Custom errors are available from solidity version 0.8.4. The instances below match or exceed that version
//Links to githubfile https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L84 https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L102 https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L103 https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L108 https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L189 https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L200 https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L255 https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L256 https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L300 https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L313 https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L328 https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L358 https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L365 https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L395 https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L416
//actual codes which shows the use. contracts/Witch.sol:84: require(param == "ladle", "Unrecognized"); contracts/Witch.sol:102: require(initialOffer <= 1e18, "InitialOffer above 100%"); contracts/Witch.sol:103: require(proportion <= 1e18, "Proportion above 100%"); contracts/Witch.sol:108: require(proportion >= 0.01e18, "Proportion below 1%"); contracts/Witch.sol:189: require(cauldron.level(vaultId) < 0, "Not undercollateralized"); contracts/Witch.sol:200: require(limits_.sum <= limits_.max, "Collateral limit reached"); contracts/Witch.sol:255: require(auction_.start > 0, "Vault not under auction"); contracts/Witch.sol:256: require(cauldron.level(vaultId) >= 0, "Undercollateralized"); contracts/Witch.sol:300: require(auction_.start > 0, "Vault not under auction"); contracts/Witch.sol:313: require(liquidatorCut >= minInkOut, "Not enough bought"); contracts/Witch.sol:328: require(baseJoin != IJoin(address(0)), "Join not found"); contracts/Witch.sol:358: require(auction_.start > 0, "Vault not under auction"); contracts/Witch.sol:365: require(liquidatorCut >= minInkOut, "Not enough bought"); contracts/Witch.sol:395: require(ilkJoin != IJoin(address(0)), "Join not found"); contracts/Witch.sol:416: require(auction_.start > 0, "Vault not under auction");
0 is less efficient than != 0 for unsigned integers (with proof)
!= 0costs less gas compared to> 0for unsigned integers inrequirestatements with the optimizer enabled (6 gas) Proof: While it may seem that> 0is cheaper than!=, this is only true without the optimizer enabled and outside a require statement. If you enable the optimizer at 10k AND you’re in arequirestatement, this will save gas. You can see this tweet for more proofs:
//Links to githubfile https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L255 https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L300 https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L358 https://github.com/code-423n4/2022-07-yield/blob/6ab092b8c10e4dabb470918ae15c6451c861655f/contracts/Witch.sol#L416
//actual codes contracts/Witch.sol:255: require(auction_.start > 0, "Vault not under auction"); contracts/Witch.sol:300: require(auction_.start > 0, "Vault not under auction"); contracts/Witch.sol:358: require(auction_.start > 0, "Vault not under auction"); contracts/Witch.sol:416: require(auction_.start > 0, "Vault not under auction");