Optimise Shipment#to_package

[Matt-Yorkley]

What? Why?

This performance improvement is added in a Spree 2.2 commit to reduce the amount of processing done in larger orders. Spotted when looking at adjustments changes in 2-2-stable.

See: spree/spree@ab01b1e for details.

What should we test?

The #to_package method is used when checking different shipping rates for an order, and when calculating some adjustments. Maybe sanity check switching shipping methods at checkout and placing an order (with lots of items in the order, not just one)?

Release notes

Changelog Category: Technical changes

Backported a performance improvement for Shipment#to_package

[sauloperez]

Maybe sanity check switching shipping methods at checkout and placing an order (with lots of items in the order, not just one)?

@Matt-Yorkley would you mind checking if that's automated already?

[filipefurtad0]

I've got this one @sauloperez 👍
This is the next chunk to be removem on manual release testing steps. This is the right opportunity to do it, so I'll test manually only what in not covered in specs.

Thanks for bringing this up!

[Matt-Yorkley]

I think there are various specs that already cover this in different ways, I just thought a quick sanity-check might be a good idea just to make extra sure. It's a fairly simple change, but the #to_package logic is something we really don't want to break...

[filipefurtad0]

Hey @Matt-Yorkley ,

I've made a brief sanity check here:

• creating a shipping method with a fee, as a hub manager
• placed an order with 40 line items in the shopfront (customer), selecting the newly created shipping method
• in the BO, edited the order and:
• switched between payment methods -> for 40 items, the page took around 10 sec. to load (before this PR it took more or less the same time -> maybe this is an inappropriate test for performance, or more line items are needed in the order?)

Met pre-existing issues: #6300 and #2881

Also met this UI-related: #6707

There are plenty of scenarios covered on the spec spec/features/admin/shipping_methods_spec.rb. I have some comments and questions, but they are not related to this PR, and as such maybe best discussed under #6693.

Anyway, I think this PR is good to go.

[Matt-Yorkley]

Cool. I think at the point you switched in the backoffice, the rates have already been calculated, so it won't be faster at that specific point.