Tax categories that are still in use can be soft deleted, creating silent failures

[tmtrademarked]

Tax categories which are still in use by products or line items are allowed to be deleted. This creates a silent failure mode when attempting to update the taxes for any order referring to these objects.

Solidus Version: 3.2.2

To Reproduce

1. Create a tax category and associated rate, assign it to a product, and create an order with that product.
2. Now create a new tax category, and update the rate to have only the new category and not the old.
3. Delete the old tax category via the UI.
4. Update taxes on the order, and notice that no taxes are calculated - and all existing taxes are cleared.

Current behavior The code which selects the rates for the line item will return no available rates: https://github.com/solidusio/solidus/blob/425c82f2e4716d01e4058f447ee9539ec5ab8dde/core/app/models/spree/tax/tax_helpers.rb#L11

This will result in the behavior in the bug where we clear the taxes on the order.

Expected behavior There's two things we could do to make this more obvious:

• Consider perhaps warning or raising if the tax category associated with the line item is soft deleted. That would turn this from a silent failure into a loud failure that would be more noticeable.
• Consider disallowing archiving a tax category that is still "in use" by products/variants/line_items/shipping_methods. That would stop this bug from ever occurring.

[gsmendoza]

Hi @tmtrademarked ! I tried to test this but I wasn't able to reproduce Step 4: Update taxes on the order. Please see the video below. Am I missing something?

https://www.loom.com/share/ec029cc36b39472d98308c8df9a7a1bb

[tmtrademarked]

Hey @gsmendoza - thanks for the detailed test video! That was super helpful. I think the missing piece here is that you have to cause taxes to be recalculated on the order. That's what I meant by "update taxes on the order".

So you can trigger this by starting a reimbursement for an item, for instance - or I think by simply doing order.recalculate in a rails console. At that point, it should cause the taxes to be zeroed out on the line item.

[gsmendoza]

@tmtrademarked I've done the following:

1. Create a tax category and associated rate, assign it to a product, and create an order with that product.
2. Now create a new tax category, and update the rate to have only the new category and not the old.
3. Assign the product to the new category.
4. Delete the old tax category via the UI.
5. Update taxes on the order.

I've confirmed that even if I assigned the product to the new category before deleting the old category, the tax rate is no longer applied to the order.

I'll check with the team what should be the expected behavior for this issue :+1:

[kennyadsl]

@gsmendoza did you already bring this to the team's attention?

[gsmendoza]

@kennyadsl Yes, I brought it up in slack and created a ticket for it.