Owner Transfer Facet

Manages diamond ownership and transfers

Key Features

• Manages diamond ownership via external functions.
• Leverages diamond storage for owner state.
• Provides exportSelectors for facet discovery.
• Compatible with ERC-2535 diamond standard.

Overview

This facet provides external functions for managing the ownership of a Compose diamond. It enables transferring ownership and renouncing it, interacting with diamond storage for owner information. Developers integrate this facet to establish clear ownership and control within their diamond architecture.

Storage

OwnerStorage

Definition

struct OwnerStorage {
  address owner;
}

State Variables

Property	Type	Description
STORAGE_POSITION	bytes32	Diamond storage slot position for this module (Value: keccak256("erc173.owner"))

Functions

transferOwnership

Set the address of the new owner of the contract. Set _newOwner to address(0) to renounce any ownership.

function transferOwnership(address _newOwner) external;

Parameters:

Property	Type	Description
_newOwner	address	The address of the new owner of the contract.

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exportSelectors

Exports the function selectors of the OwnerTransferFacet This function is use as a selector discovery mechanism for diamonds

function exportSelectors() external pure returns (bytes memory);

Returns:

Property	Type	Description
-	bytes	selectors The exported function selectors of the OwnerTransferFacet

Events

Signature:

event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

Errors

Signature:

error OwnerUnauthorizedAccount();

Best Practices

Best Practice

• Initialize the owner address during diamond deployment.
• Enforce access control for state-changing functions like transferOwnership.
• Verify compatibility with OwnerDataFacet and OwnerRenounceFacet when composing access control functionalities.

Security Considerations

Security

State-changing functions, particularly transferOwnership, must be protected by appropriate access control mechanisms (e.g., Ownable or role-based access control) to prevent unauthorized ownership changes. Ensure the caller has the necessary permissions before executing transferOwnership. Renouncing ownership by setting the new owner to address(0) is irreversible. Follow standard Solidity security practices for input validation and reentrancy.

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Last updated:March 13, 2026