Resolving Undefined Variable Errors in WooCommerce Custom Code

In a recent Business Bloomer Club thread, a member encountered an undefined variable error in a WooCommerce snippet they were using to display custom order statuses on the admin dashboard.

Despite the functionality working correctly, Query Monitor flagged an error message due to a missing initial value for a PHP variable. Properly initializing this variable before using it is essential to prevent PHP errors and ensure code stability.

Here’s a breakdown of the issue and a step-by-step solution to help avoid similar problems in your custom WooCommerce snippets.

Issue: Undefined Variable $custom_order_status_count

The error arose because $custom_order_status_count was being incremented without first being assigned an initial value. When PHP encounters this, it triggers a warning since there’s no baseline value for the addition operation.

Original Code Snippet

add_action( 'woocommerce_after_dashboard_status_widget', 'bbloomer_custom_order_status_counter' );
function bbloomer_custom_order_status_counter() {
    if ( ! current_user_can( 'edit_shop_orders' ) ) return;
    foreach ( wc_get_order_types( 'order-count' ) as $type ) {
        $counts = (array) wp_count_posts( $type );
        $custom_order_status_count += isset( $counts['wc-custom-status'] ) ? $counts['wc-custom-status'] : 0;
    }
    // Output code for dashboard widget
}

Solution: Initialize the Variable Before Use

To resolve the error, simply add an initialization line for $custom_order_status_count right after the capability check. This sets the initial value to 0, allowing the += operation to proceed without issues.

Updated Code with Fix

add_action( 'woocommerce_after_dashboard_status_widget', 'bbloomer_custom_order_status_counter' );
function bbloomer_custom_order_status_counter() {
    if ( ! current_user_can( 'edit_shop_orders' ) ) return;
    $custom_order_status_count = 0; // Initialize the variable
    foreach ( wc_get_order_types( 'order-count' ) as $type ) {
        $counts = (array) wp_count_posts( $type );
        $custom_order_status_count += isset( $counts['wc-custom-status'] ) ? $counts['wc-custom-status'] : 0;
    }
    // Output code for dashboard widget
}

Final Thoughts

Initializing variables is a fundamental step to avoid errors and warnings in PHP, especially when performing operations like addition. Following these practices ensures cleaner code and avoids potential issues in both development and production environments.

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Rodolfo Melogli

Business Bloomer Founder

Author, WooCommerce expert and WordCamp speaker, Rodolfo has worked as an independent WooCommerce freelancer since 2011. His goal is to help entrepreneurs and developers overcome their WooCommerce nightmares. Rodolfo loves travelling, chasing tennis & soccer balls and, of course, wood fired oven pizza. Follow @rmelogli

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