interface-lint

Interface Lint

Format Solidity interface files following EigenLayer's established conventions for organization, documentation, and error code generation.

Interface Structure

Every interface file should contain four interface contracts in this order:

1. I{ContractName}Errors - All custom errors
2. I{ContractName}Types - All structs and enums
3. I{ContractName}Events - All events (inherits Types for struct access)
4. I{ContractName} - Main interface (inherits Errors and Events)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.27;

// Imports

interface I{ContractName}Errors {
    // All errors with error codes
}

interface I{ContractName}Types {
    // All structs and enums
}

interface I{ContractName}Events is I{ContractName}Types {
    // All events
}

interface I{ContractName} is I{ContractName}Errors, I{ContractName}Events {
    // All function declarations
}

Error Documentation

Each error MUST include:

1. @notice describing when the error is thrown
2. @dev Error code: 0x... with the 4-byte selector from cast sig

Generating Error Codes

Use cast sig to generate the error code:

cast sig "InvalidOperatorSet()"
# Output: 0x7ec5c154

Error Format

interface IContractNameErrors {
    /// @notice Thrown when the operator set is not valid
    /// @dev Error code: 0x7ec5c154
    error InvalidOperatorSet();

    /// @notice Thrown when the chainId is invalid
    /// @dev Error code: 0x7a47c9a2
    error InvalidChainId();

    /// @notice Thrown when the key type is not set for the operatorSet
    /// @dev Error code: 0xe57cacbd
    /// @dev Additional context about why this is required
    error KeyTypeNotSet();
}

Types Documentation

Each struct/enum MUST include:

1. @notice with a brief description
2. @param for each field in structs

interface IContractNameTypes {
    /// @notice A per-operatorSet configuration struct
    /// @param owner the permissioned owner of the OperatorSet
    /// @param maxStalenessPeriod the maximum staleness period in seconds
    struct OperatorSetConfig {
        address owner;
        uint32 maxStalenessPeriod;
    }

    /// @notice Represents the status of an operator's registration
    /// @param registered Whether the operator is currently registered
    /// @param slashableUntil Block until which the operator remains slashable
    struct RegistrationStatus {
        bool registered;
        uint32 slashableUntil;
    }
}

Event Documentation

Each event MUST include a singular @notice describing when the event is emitted:

interface IContractNameEvents is IContractNameTypes {
    /// @notice Emitted when a generation reservation is created
    event GenerationReservationCreated(OperatorSet operatorSet);

    /// @notice Emitted when an operator set config is set
    event OperatorSetConfigSet(OperatorSet operatorSet, OperatorSetConfig config);

    /// @notice Emitted when a chainID is added to the whitelist
    event ChainIDAddedToWhitelist(uint256 chainID, address operatorTableUpdater);
}

Function Documentation

Each function in the main interface MUST include:

1. @notice - What the function does
2. @param - Description for each parameter
3. @return - Description for each return value (for view functions)
4. @dev - Additional context (optional, but include caller requirements)
5. @dev Reverts for: - List ALL revert conditions
6. @dev Emits the following events: - List ALL events emitted

Function Documentation Format

interface IContractName is IContractNameErrors, IContractNameEvents {
    /// @notice Creates a generation reservation for cross-chain transport
    /// @param operatorSet the operatorSet to make a reservation for
    /// @param operatorTableCalculator the calculator contract address
    /// @param config the config containing owner and staleness period
    /// @dev msg.sender must be an authorized caller for operatorSet.avs
    /// @dev Reverts for:
    ///      - CurrentlyPaused: Generation reservations are paused
    ///      - InvalidPermissions: Caller is not authorized
    ///      - InvalidOperatorSet: The operatorSet does not exist
    ///      - GenerationReservationAlreadyExists: Reservation already exists
    ///      - InvalidStalenessPeriod: The maxStalenessPeriod is invalid
    /// @dev Emits the following events:
    ///      - GenerationReservationCreated: When the reservation is created
    ///      - OperatorTableCalculatorSet: When the calculator is set
    ///      - OperatorSetConfigSet: When the config is set
    function createGenerationReservation(
        OperatorSet calldata operatorSet,
        IOperatorTableCalculator operatorTableCalculator,
        OperatorSetConfig calldata config
    ) external;

    /// @notice Gets the operator set config
    /// @param operatorSet the operatorSet to query
    /// @return The OperatorSetConfig for the given operatorSet
    /// @dev You should check if an operatorSet has an active reservation first
    function getOperatorSetConfig(
        OperatorSet memory operatorSet
    ) external view returns (OperatorSetConfig memory);
}

Revert Conditions Format

List each revert condition with the error name and when it occurs:

/// @dev Reverts for:
///      - CurrentlyPaused: Generation reservations are paused
///      - InvalidPermissions: Caller is not an authorized caller for operatorSet.avs
///      - InvalidOperatorSet: The operatorSet does not exist in the AllocationManager
///      - GenerationReservationAlreadyExists: A generation reservation already exists

For Ownable errors, use the string format:

/// @dev Reverts for:
///      - "Ownable: caller is not the owner": Caller is not the owner

Events Emitted Format

List each event with a brief description of when it's emitted:

/// @dev Emits the following events:
///      - GenerationReservationCreated: When the reservation is successfully created
///      - OperatorTableCalculatorSet: When the calculator is set for the operatorSet
///      - OperatorSetConfigSet: When the config is set for the operatorSet

View Functions

View functions typically don't revert (except for input validation) and don't emit events. Document them simpler:

/// @notice Gets the active generation reservations
/// @return An array of operatorSets with active generationReservations
function getActiveGenerationReservations() external view returns (OperatorSet[] memory);

/// @notice Gets reservations by range for pagination
/// @param startIndex the start index of the range, inclusive
/// @param endIndex the end index of the range, exclusive
/// @return An array of operatorSets in the specified range
/// @dev Reverts for:
///      - InvalidRange: startIndex is greater than endIndex
///      - InvalidEndIndex: endIndex exceeds array length
function getActiveGenerationReservationsByRange(
    uint256 startIndex,
    uint256 endIndex
) external view returns (OperatorSet[] memory);

Complete Example

Reference: src/contracts/interfaces/ICrossChainRegistry.sol

This file demonstrates the full pattern with:

• Errors interface with cast sig error codes
• Types interface with documented structs
• Events interface inheriting Types
• Main interface with full function documentation

Checklist for Linting an Interface

1. ☐ Split into Errors, Types, Events, and main interface contracts
2. ☐ Errors have @notice and @dev Error code: 0x... (use cast sig)
3. ☐ Types have @notice and @param for each field
4. ☐ Events have singular @notice describing when emitted
5. ☐ Events interface inherits Types interface
6. ☐ Main interface inherits Errors and Events interfaces
7. ☐ Functions have @notice, @param, and @return (for views)
8. ☐ Functions list ALL revert conditions under @dev Reverts for:
9. ☐ Functions list ALL events under @dev Emits the following events:
10. ☐ View functions document reverts only when they can revert

Generating All Error Codes

To generate error codes for an entire interface:

# For each error in the interface, run:
cast sig "ErrorName()"
cast sig "ErrorName(uint256)"  # Include params if error has them

# Example output:
# 0x7ec5c154  # InvalidOperatorSet()
# 0x7a47c9a2  # InvalidChainId()

Common Error Patterns

Error	Typical Code	Usage
InvalidOperatorSet()	0x7ec5c154	OperatorSet doesn't exist
InvalidPermissions()	varies	Caller not authorized
InvalidCaller()	varies	Wrong msg.sender
ArrayLengthMismatch()	0xa24a13a6	Input arrays have different lengths