PHP Warning: Undefined array key “enabled” after update to 4.0.13

PHP Warning: Undefined array key “enabled” after update to 4.0.13

After updating Payment Plugins for Stripe WooCommerce to version 4.0.13, the following PHP warning started appearing repeatedly:

PHP Warning: Undefined array key "enabled" in
/wp-content/plugins/woo-stripe-payment/includes/class-wc-stripe-product-gateway-option.php on line 113

The issue is in WC_Stripe_Product_Gateway_Option::get_option():

public function get_option( $key, $default = null ) {
    if ( ! isset( $this->settings[ $key ] ) && null != $default ) {
        $this->settings[ $key ] = $default;
    }

    return $this->settings[ $key ];
}

enabled() calls:

return $this->get_option( 'enabled', false );

Because the comparison in get_option() is non-strict (null != $default), it evaluates to false when $default is boolean false. Therefore, if the enabled key is missing, the default value is not assigned and the subsequent array access triggers the PHP warning.

I tested the following fix successfully:

public function get_option( $key, $default = null ) {
    if ( ! isset( $this->settings[ $key ] ) && null !== $default ) {
        $this->settings[ $key ] = $default;
    }

    return $this->settings[ $key ] ?? $default;
}

This changes the comparison to strict (!==) and also safely returns the supplied default if the key is absent.

Could you please include this fix in the next release?