Error "Constant WCCT_VERSION already defined" in WooCommerce Conversion Tracking plugin

[andersonnarciso]

Hey guys! How are u?

I am encountering an error while using the WooCommerce Conversion Tracking plugin. The issue arises from the redefinition of the constant WCCT_VERSION, resulting in the following warning in the PHP error log:

[13-Dec-2024 15:09:41 UTC] PHP Warning: Constant WCCT_VERSION already defined in /nvme3/user/public_html/wp-content/plugins/woocommerce-conversion-tracking/conversion-tracking.php on line 153

The problem originates in the define_constants method, where multiple constants are defined without checking if they are already defined.

Location of the issue:
File: conversion-tracking.php
Method: define_constants

Current Code:

public function define_constants() {
define( 'WCCT_VERSION', $this->version );
define( 'WCCT_FILE', FILE );
define( 'WCCT_PATH', dirname( WCCT_FILE ) );
define( 'WCCT_INCLUDES', WCCT_PATH . '/includes' );
define( 'WCCT_URL', plugins_url( '', WCCT_FILE ) );
define( 'WCCT_ASSETS', WCCT_URL . '/assets' );
}

The constants are being redefined without verification, causing the error when the plugin or its components are loaded multiple times.

Proposed Solution:

Update the define_constants method to check if each constant is already defined before defining it. Here's a corrected version of the method:

public function define_constants() {
if ( ! defined( 'WCCT_VERSION' ) ) {
define( 'WCCT_VERSION', $this->version );
}

if ( ! defined( 'WCCT_FILE' ) ) {
    define( 'WCCT_FILE', __FILE__ );
}

if ( ! defined( 'WCCT_PATH' ) ) {
    define( 'WCCT_PATH', dirname( WCCT_FILE ) );
}

if ( ! defined( 'WCCT_INCLUDES' ) ) {
    define( 'WCCT_INCLUDES', WCCT_PATH . '/includes' );
}

if ( ! defined( 'WCCT_URL' ) ) {
    define( 'WCCT_URL', plugins_url( '', WCCT_FILE ) );
}

if ( ! defined( 'WCCT_ASSETS' ) ) {
    define( 'WCCT_ASSETS', WCCT_URL . '/assets' );
}

}

Steps to Reproduce the Issue:

Activate the WooCommerce Conversion Tracking plugin in WordPress.
Monitor the PHP error logs or enable debug mode (WP_DEBUG).
The error occurs whenever the define_constants method attempts to redefine constants that already exist.
Environment:

WordPress Version: 6.7.1
PHP Version: 8+
WooCommerce Conversion Tracking Version: 2.1.0
Active Theme: WoodMart

Impact:
The error does not break the plugin's core functionality but pollutes the error logs and may cause compatibility issues with other plugins or themes.