Add support for High Performance Order Storage

[lakrisgubben]

Hey,

as y'all may have heard WooCommerce are changing how orders are stored with the project High Performance Order Storage (HPOS), as of now it's scheduled to be enabled by default starting with WooCommerce 8.0 scheduled for release on 2023-08-08.

Some high level overview of the project here: https://developer.woocommerce.com/2022/09/14/high-performance-order-storage-progress-report/ and some guidelines for extension developers here: https://github.com/woocommerce/woocommerce/wiki/High-Performance-Order-Storage-Upgrade-Recipe-Book

I've started to audit the codebases for some of my customers using WooCommerce and the upgrade path is quite straight forward, mainly consisting of changing all interactions with orders to use WooCommerce's API:s instead of WordPress's post API:s.

I had a look through this plugin and there are a few changes to be made, I've started some work to test it out and make sure the plugin works both with HPOS and the current method where orders are stored as posts, happy to submit a PR if y'all are interested and haven't started working on this already.

[lakrisgubben]

Made two PR:s SwedbankPay/swedbank-pay-woocommerce-core#89 and #144 with the things I've found so far while testing out HPOS. There are probably more things to fix (and I haven't tried the subscription functionality) but this at least makes the base functionality of handling payments work.

[lakrisgubben]

Update from the WooCommerce team on HPOS, it's on track to be enabled by default starting in August: https://developer.woocommerce.com/2023/03/07/high-performance-order-storage-is-soon-to-be-the-new-normal/

[lakrisgubben]

Hey,

just wanted to check in on this. Any status update on when you'll support HPOS?

WooCommerce have delayed making HPOS the default for new stores until 8.2 which should be released in October: https://developer.woocommerce.com/2023/08/04/hpos-full-rollout-delayed/

[lakrisgubben]

Hey y'all,

WooCommerce 8.2 was released yesterday with HPOS enabled by default for new stores: https://developer.woocommerce.com/2023/10/10/woocommerce-8-2-0-released/

Anyt status updates on this plugins support for HPOS. Happy to update my PR #144 if that would help getting this issue resolved.