In the provided PHP code, what potential issues or pitfalls can be identified in the logic for redirecting back to login.php?

The potential issue in the provided PHP code is that the redirect back to login.php is unconditional, meaning it will always redirect regardless of whether the login attempt was successful or not. To solve this issue, you can add a conditional check to only redirect back to login.php if the login attempt failed.

// Check if the login attempt failed before redirecting back to login.php
if ($login_successful) {
    // Login successful, redirect to homepage
    header("Location: homepage.php");
    exit();
} else {
    // Login failed, redirect back to login.php
    header("Location: login.php");
    exit();
}