Nouns DAO contest - SaharAP's results

1. Not to initialize uint variables to zero

Uint variable's default value is zero. So, you can save gas by just defining uint variables.

Proof of Concept

getPriorVotes() queue()

Recommended Mitigation Steps

You can just define uint32 lower without initializing it to zero. Also, there are many for loops in NounsDAOLogicV2 and NounsDAOLogicV1 contracts that you can just define uint256 i without initializing it.

2. Use unchecked block if possible

Use unchecked blocks for arithmetic operations that can't underflow/overflow.

Proof of Concept

queue()

Recommended Mitigation Steps

You can put ++i or i++ in for loops in an unchecked block.

3. Use !=0 instead of > 0

!= 0 is a cheaper operation compared to > 0, when dealing with uint. > 0 can be replaced with != 0 for gas optimization.

Proof of Concept

castRefundableVoteInternal() _writeQuorumParamsCheckpoint() getCurrentVotes() _moveDelegates() _moveDelegates() _moveDelegates() _writeCheckpoint()

Recommended Mitigation Steps

Replace > 0 with != 0 when comparing unsigned integer variables to save gas.

4. Use custom errors instead of require() statements with revert strings.

Using custom errors can save gas instead of using string errors.

Proof of Concept

initialize() propose() tokenOfOwnerByIndex tokenByIndex

Recommended Mitigation Steps

Internal functions used once can be written inline to save gas.

5. Use inline code instead of writing functions.

Proof of Concept

safe32() safe96() add96() sub96() getChainId() getChainIdInternal() queueOrRevertInternal() _refundGas()

Recommended Mitigation Steps

Write safe32(), safe96(), add96(), sub96 and getChainId() functions inside their calling functions.

6. Cache an array length in a memory variable to save gas

targets.length is read multiple times, especially in loops, you should cache it in a memory variable to save gas.

Proof of Concept

propose() queue() execute() cancel() veto()

Recommended Mitigation Steps

Store targets.length in a memory variable to save gas.

7. Use external visibility for uncalled public functions

Public functions that are never called from within the contracts should be declared external to save gas.

Proof of Concept

delegate()

Recommended Mitigation Steps

Change delegate() function visiblity from public to external.