WooCommerce Bug Fix: SyntaxError: Unexpected Token (2.4+)

Just as a favor to anyone out there that may be experiencing this issue with WooCommerce as of 2.4, I wanted to post the solution that we found. I’m sure this won’t be the end-all solution for everyone, but it may help some of you.

WooCommerce Checkout Not Working Upon Update

Check that your payment gateway isn’t using this method:

$order->payment_complete();

For some reason, using that method had always worked in the past, but now was triggering some non-JSON responses upon checkout. Instead, manually update the stock levels and status like so:

$order->update_status('processing', __( 'Awaiting fulfillment.', 'woocommerce' ));

// Reduce stock levels
$order->reduce_order_stock();

// Remove cart
WC()->cart->empty_cart();

Hope this saves someone a lot of headache!