Missing events access control

Severity: Low ID: missing-events-access-control

Flags protected entry-point functions that update state used for access control without emitting an event.

What it does

This lint looks for mutable state variables that are:

• read by an access-control check involving msg.sender or tx.origin,
• written by a public or external state-mutating function with access control, and
• assigned from function input, msg.sender, another access-control state variable, or a keyed mapping write, directly or through local aliases/internal helpers, and
• changed without a related event that includes the same value or key source.

It intentionally skips constructors, unprotected setters, variables not used in authorization checks, unrelated events, and fixed writes other than clearing the state variable currently used by the access guard. Those limits keep the rule focused on Slither's low-severity events-access case while avoiding common false positives.

Why is this bad?

Off-chain monitors, users, and auditors often rely on events to track changes to owners, guardians, roles, and other authority-bearing state. If a protected function silently changes access control, critical permission updates are harder to review and investigate.

Example

Bad

function transferOwnership(address newOwner) external onlyOwner {
    owner = newOwner;
}

Good

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

function transferOwnership(address newOwner) external onlyOwner {
    address oldOwner = owner;
    owner = newOwner;
    emit OwnershipTransferred(oldOwner, newOwner);
}