What potential issue arises when using isset() to check for a cookie before executing code in PHP?

Using isset() to check for a cookie before executing code in PHP can lead to potential issues because isset() returns true even if the cookie is set to an empty string. To solve this issue, you should use the function empty() instead of isset() to check if the cookie is empty or not set at all.

if (!empty($_COOKIE['cookie_name'])) {
    // Code to execute if the cookie is not empty
}