AbstractCCIPMessagingUpgradeable Code Style Findings

ACC-01C: Generic Typographic Mistake

Type	Severity	Location
Code Style		AbstractCCIPMessagingUpgradeable.sol:L152

Description:

The referenced line contains a typographical mistake (i.e. private variable without an underscore prefix, a non-snake_case module) or generic documentational error (i.e. copy-paste) that should be corrected.

Example:

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152*      this involves burning tokens on the bridged/destination chain.

Recommendation:

We advise this to be done so to enhance the legibility of the codebase.

Alleviation (c5b31e01e4d5cf94e0ef3523780c4aac764127bf):

The referenced documentation was corrected to indicate that the tokens are extracted on the origin chain rather than the target / destination chain.

ACC-02C: Incorrect Exposure of Function

Type	Severity	Location
Gas Optimization		AbstractCCIPMessagingUpgradeable.sol:L288-L290

Description:

The AbstractCCIPMessagingUpgradeable::authorizeUpgrade function that has been set as publicly accessible is redundant as it results in a no-op and simply applies access control.

Example:

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283/**
284 * @notice Authorizes an upgrade to a new implementation.
285 * @param newImplementation The address of the new implementation.
286 * @dev Only callable by the contract owner.
287 */
288function authorizeUpgrade(address newImplementation) public {
289    _authorizeUpgrade(newImplementation);
290}

Recommendation:

We advise it to be omitted, optimizing the bytecode size of the contract.

Alleviation (c5b31e01e4d5cf94e0ef3523780c4aac764127bf):

The publicly-available AbstractCCIPMessagingUpgradeable::authorizeUpgrade function has been removed as a result of this exhibit, addressing it in the process.

ACC-03C: Inexistent Configuration of Indexed Arguments

Type	Severity	Location
Standard Conformity		AbstractCCIPMessagingUpgradeable.sol: • I-1: L38 • I-2: L54 • I-3: L65

Description:

The referenced events do not emit any indexed arguments rendering off-chain filtering computationally expensive.

Example:

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36event CCIPMessageReceived(
37    bytes32 messageId,
38    uint64 sourceChainSelector,
39    address tokenSender,
40    address tokenReceiver,
41    uint256 tokenAmount
42);

Recommendation:

We advise the chain ID variables on each argument to be set as indexed, permitting all operations from or toward a particular chain ID to be filtered optimally.

Alleviation (c5b31e01e4d5cf94e0ef3523780c4aac764127bf):

An indexed argument has been introduced across all referenced event declarations, addressing this exhibit.

ACC-04C: Sub-Optimal Contract Initialization

Type	Severity	Location
Gas Optimization		AbstractCCIPMessagingUpgradeable.sol:L115, L128

Description:

The AbstractCCIPMessagingUpgradeable::__AbstractCCIPMessagingUpgradeable_init function will invoke the AbstractCCIPMessagingUpgradeable::setCCIPRouter function that applies the OwnableUpgradeable::onlyOwner modifier redundantly.

Example:

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106/**
107 * @notice Initializes the contract.
108 * @param _owner The address of the contract owner.
109 * @param _ccipRouter The address of the Chainlink CCIP router.
110 * @dev This function should be called during the contract's deployment or upgrade process.
111 */
112function __AbstractCCIPMessagingUpgradeable_init(address _owner, address _ccipRouter) internal onlyInitializing {
113    __Ownable_init(_owner);
114    __UUPSUpgradeable_init();
115    setCCIPRouter(_ccipRouter);
116}
117
118// ┌─────────────────────────────────────────────────────────────┐
119// | Admin functions                                             |
120// └─────────────────────────────────────────────────────────────┘
121
122/**
123 * @notice Sets the CCIP router address.
124 * @param _ccipRouter The new address of the CCIP router.
125 * @dev Only callable by the contract owner. Setting to zero disables CCIP bridging.
126 * @dev Zero address is allowed (which becomes an 'unset').
127 */
128function setCCIPRouter(address _ccipRouter) public onlyOwner {
129    ccipRouter = _ccipRouter;
130    emit CCIPRouterUpdated(_ccipRouter);
131}

Recommendation:

We advise the code of the AbstractCCIPMessagingUpgradeable::setCCIPRouter function to be internalized to an internal and underscore-prefixed (_) function variant with no access control, permitting both functions to invoke it optimally.

Alleviation (c5b31e01e4d5cf94e0ef3523780c4aac764127bf):

The code was refactored per our recommendation, permitting an internally available AbstractCCIPMessagingUpgradeable::_setCCIPRouter function to be invoked by the AbstractCCIPMessagingUpgradeable::__AbstractCCIPMessagingUpgradeable_init function in an optimal way.