Cap Code Style Findings

CPA-01C: Generic Typographic Mistakes

Type	Severity	Location
Code Style		Cap.sol:L18, L19, L20, L21, L22

Description:

The referenced lines contain typographical mistakes (i.e. private variable without an underscore prefix) or generic documentational errors (i.e. copy-paste) that should be corrected.

Example:

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18uint256 _load;

Recommendation:

We advise them to be corrected enhancing the legibility of the codebase.

Alleviation (58e8cc66dfa900c03c47df78f5170d9960005629):

All referenced variables have been renamed accordingly, omitting their underscore prefix for the sake of legibility as they do not constitute actual private / internal variables.

CPA-02C: Ineffectual Usage of Safe Arithmetics

Type	Severity	Location
Language Specific		Cap.sol:L161

Description:

The linked mathematical operation is guaranteed to be performed safely by surrounding conditionals evaluated in either require checks or if-else constructs.

Example:

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157uint256 subbed = calcSubbed(amount);
158
159StorageV1 storage $ = _getStorageV1();
160
161$._load -= subbed;

Recommendation:

Given that safe arithmetics are toggled on by default in pragma versions of 0.8.X, we advise the linked statement to be wrapped in an unchecked code block thereby optimizing its execution cost.

Alleviation (58e8cc66dfa900c03c47df78f5170d9960005629):

The subtraction is safely performed in an unchecked code block, optimizing the code's gas cost.

CPA-03C: Loop Iterator Optimizations

Type	Severity	Location
Gas Optimization		Cap.sol:L91, L187, L230, L263

Description:

The linked for loops increment / decrement their iterator "safely" due to Solidity's built - in safe arithmetics (post-0.8.X).

Example:

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91for (uint256 i = 0; i < domains.length; i++) {

Recommendation:

We advise the increment / decrement operations to be performed in an unchecked code block as the last statement within each for loop to optimize their execution cost.

Alleviation (58e8cc66dfa900c03c47df78f5170d9960005629):

The referenced loop iterator increment statements have been relocated at the end of each respective for loop's body and have been unwrapped in an unchecked code block, optimizing their gas cost.

CPA-04C: Redundant Initialization of Values

Type	Severity	Location
Gas Optimization		Cap.sol:L49-L52

Description:

Unless the Cap contract acts as an upgrade, initializing values to 0 is redundant as all values contain that value by default.

Example:

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46function initialize(address owner, address hook, address ism) public initializer {
47    _MailboxClient_initialize(hook, ism, owner);
48
49    StorageV1 storage $ = _getStorageV1();
50    $._epoch[localDomain] = 0;
51    $._load = 0;
52    $._ready = false;
53}

Recommendation:

We advise the referenced statements to be omitted if the contract is meant to be freshly deployed, optimizing its gas cost.

Alleviation (58e8cc66dfa900c03c47df78f5170d9960005629):

The redundant initializations of the _load and _ready variables have been safely omitted, optimizing the code's gas cost.

CPA-05C: Redundant Repetitive Invocation of Getter Function

Type	Severity	Location
Gas Optimization		Cap.sol:L92

Description:

The Cap::_getStorageV1 function will be invoked domains.length times within the Cap::remoteEpochs function redundantly.

Example:

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91for (uint256 i = 0; i < domains.length; i++) {
92    remoteEpochs_[i] = _getStorageV1()._epoch[domains[i]];
93}

Recommendation:

We advise its value to be cached outside the for loop, optimizing the function's gas cost.

Alleviation (58e8cc66dfa900c03c47df78f5170d9960005629):

The CapStorageV1::_getStorageV1 function result is now properly cached outside the for loop thereby optimizing its gas cost.