What steps can PHP developers take to troubleshoot issues with custom hooks not working as expected in WordPress plugins like WPML?

When custom hooks are not working as expected in WordPress plugins like WPML, PHP developers can troubleshoot the issue by first checking if the hook is correctly registered and if the callback function is properly defined. They can also verify if there are any conflicts with other plugins or themes that may be affecting the hook execution. Additionally, developers can use debugging tools like WP_DEBUG to identify any errors or warnings that may be causing the issue.

// Check if the custom hook is properly registered
if ( has_action( 'custom_hook_name' ) ) {
    // Define the callback function for the custom hook
    function custom_hook_callback_function() {
        // Code to execute when the custom hook is triggered
    }
    
    // Add the callback function to the custom hook
    add_action( 'custom_hook_name', 'custom_hook_callback_function' );
} else {
    // Output a message if the custom hook is not registered
    echo 'Custom hook is not properly registered.';
}