Fixes#6435 i.e. If the customer paid for their order by Stripe/Paypal then the Enterprise needs to know that the order was cancelled in order to arrange a refund. Refunds are not automatically processed when an order is cancelled.
This will send a very basic email to the shop, it only includes a link to view the cancelled order in the admin area initially.
I created a CustomerOrderCancellation object here because orders can be cancelled in two ways (1) by the customer, so an email should be sent to the shop. (2) by the shop, so an email doesn't need to be sent. However the code for cancelling order happens in Order#cancel via the state machine. Rather than passing some sort of parameter into #cancel to indicate whether it is a customer or shop cancelled order it might be clearer to have a CustomerOrderCancellation object, there could be other differences between customer or shop cancelled orders in future maybe.
This method returns the same thing as the Spree::Order#line_items_adjustments scope, but in a slightly less useful format (an array instead of a relation). The method's name is also totally inaccurate, as currently the only adjustments that appear on line items are tax adjustments for inclusive tax rates, which by definition have no effect on the price whatsoever...
When the user entered a number beyond the stock level, the browser was
correcting that to the max number which is very helpful. But Angular was
setting the model to undefined which removes the item from the cart.
Deactivating Angular's max behaviour let's us set the value ourselves
which is then used in the cart.
If the user entered an invalid quantity, Angular set the model to
undefined and we removed the input field to show the add button. That
makes it impossible for a user to see what the maximum quantity to enter
would be. For example:
- The variant has a stock level of 5.
- The user enters 7.
- Angular sets it to undefined.
- The input field disappears.
- The user is startled and doesn't know how to proceed.
But now we hide the input only if it's deliberately set to zero.
The user can now type anything into the quantity field and some of it
may not be valid. These safe guards ensure that the buttons still work
even if the quantity is undefined or out of range.
Angular guards against the value being out of range but that has other
side-effects. We want to be able to de-activate some of Angular's
behaviour.
