Gas Optimizations

[code423n4]

Avoid decoding unused values

Severity: Gas Optimization

Context:

• https://github.com/code-423n4/2022-08-rigor/blob/5ab7ea84a1516cb726421ef690af5bc41029f88f/contracts/Project.sol#L505

Description:

In Project.raiseDispute, all values are decoded from _data, but only the first two values are used. The additional logic required to decode the last three values costs significant gas without any benefit.

Remediation:

Don't decode the final three values as they're not being used to reduce gas usage from 217449 to 216464.

Use uint256 over smaller uint types when possible

Severity: Gas Optimization

Context:

• https://github.com/code-423n4/2022-08-rigor/blob/5ab7ea84a1516cb726421ef690af5bc41029f88f/contracts/Disputes.sol#L100
• https://github.com/code-423n4/2022-08-rigor/blob/5ab7ea84a1516cb726421ef690af5bc41029f88f/contracts/Disputes.sol#L103

Description:

In Disputes.raiseDispute, _actionType is decoded from _data and casted to a uint8 type. This is unnecessary and inefficient as the necessary logic can be performed with a uint256, and when compiled, _actionType gets casted back to uint256 costing additional gas in the process.

Remediation:

Decode _actionType as a uint256 in Disputes.raiseDispute to reduce gas usage from 217449 to 217412.

Save storage variables locally when reused

Severity: Gas Optimization

Context:

• https://github.com/code-423n4/2022-08-rigor/blob/5ab7ea84a1516cb726421ef690af5bc41029f88f/contracts/Community.sol#L385
• https://github.com/code-423n4/2022-08-rigor/blob/5ab7ea84a1516cb726421ef690af5bc41029f88f/contracts/Project.sol#L190
• https://github.com/code-423n4/2022-08-rigor/blob/5ab7ea84a1516cb726421ef690af5bc41029f88f/contracts/Project.sol#L350
• https://github.com/code-423n4/2022-08-rigor/blob/5ab7ea84a1516cb726421ef690af5bc41029f88f/contracts/Project.sol#L409

Description:

Throughout Community.sol and Project.sol, there are storage variables which are reused within the same method. This should be generally avoided as it is much more efficient to save a variable locally and retrieve from the stack or memory instead of storage.

Remediation:

• In Community.lendToProject, save _communities[_communityId] to a local variable to reduce gas usage from 190993 to 190425.
• In Project.lendToProject, save builder to a local variable to reduce gas usage from 108069 to 107986
• In Project.setComplete, save tasks[_taskId] to a local variable to reduce gas usage from 93713 to 93635
• In Project.changeOrder, save tasks[_taskId] to a local variable to reduce gas usage from 75640 to 75459

Use optimal comparison operator

Severity: Gas Optimization

Context:

• Throughout the contracts

Description:

Throughout the contracts, suboptimal comparison operators are used.

Remediation:

Optimal comparison operators should be used as follows:

• When checking that uints are greater than 0, use value != 0 instead of value > 0 to save 44 gas
• When checking that a uint is less/greater than or equal to another, use, e.g. value > otherValue - 1 instead of value >= otherValue to save 38 gas