Shipping Method cannot calculate shippingcosts based on "tax_subtotal" of the quote

[EliasKotlyar]

Preconditions (*)

1. OpenMage 19.4.*

Steps to reproduce (*)

1. Create some custom module
2. Custom Module should contain a Shipping Method
3. Shipping Method should calculate Shipping based on "tax_subtotal" of the quote

Expected result (*)

It should behave like in Magento 1.9.4.x. Tax-Subtotal should be usable in the shipping calculation

Actual result (*)

You cannot use "tax-subtotal" in shipping method, as its not initialized yet with a value.

Dev-Info

In the Magento 1.9.4.4 there are following code in app/code/core/Mage/Tax/etc/config.xml, which is responsible for the sort order of total calculation:

                    <tax_subtotal>
                        <class>tax/sales_total_quote_subtotal</class>
                        <after>freeshipping</after>
                        <before>tax,discount</before>
                    </tax_subtotal>

(see https://github.com/OpenMage/magento-mirror/blob/magento-1.9/app/code/core/Mage/Tax/etc/config.xml#L165)

In Openmage, the code was changed to:

                    <tax_subtotal>
                        <class>tax/sales_total_quote_subtotal</class>
                       <after>subtotal,nominal,shipping,freeshipping</after>
                        <before>tax,discount</before>
                    </tax_subtotal>

Its unclear why it was done, but it seems to be some "upstream" upload from 1.9.3.x:
d92a24a

[ADDISON74]

If I remember well we discussed about this issue before in PR #1104

[EliasKotlyar]

I read the PR #1104 but for me its unclear what exactly is the outcome. Will it be left as it is, or is someone willing to merge the any of the PRs which are resolving this issue?

[fballiano]

as I commented #1104 (comment) it is an extremely delicate change that should be tested extensively so, at this point in the release cycle, IMHO it is impossible to merge such a change.

also, from the description of the issue, it's really hard for us to replicate the problem and understand it completely.

[fballiano]

This is the commit that introduced the change: d92a24a from 2018

[ADDISON74]

Please read my comment that I made here #1104 (comment).

There is a problem with the applied taxes in OpenMage and it should have been solved long time ago, especially the one related to the free delivery. Because it was not fixed I use only the <after>freeshipping</after> option in the config.xml file. This fix is from Magento 1.9.4.5.

An elegant solution would be that in the Backend to exist the possibility that in a multiselect field one or more options can be selected from the subtotal | nominal | shipping | freeshipping. I would leave the default version with all four options selected as before.

[fballiano]

I really don't know much about this subject, I never had problems with this with my customers so I'll leave the discussion to somebody else.

[ADDISON74]

This issue #1813 will help you understand what is going wrong and why we need to customize the options.

PR #1104 was supposed to solve the reported issues #80 and #1813 but it was closed without solid arguments.

[ADDISON74]

I am evaluating to integrate this fix in OpenMage https://github.com/ikonoshirt/TopologicalSearch. It seems it was never fixed before.

[fballiano]

@ADDISON74 it seems a great find and totally worth including it in the core!

[fballiano]

another topological sort that doesn't require an external library:

• https://stackoverflow.com/questions/11953021/topological-sorting-in-php
• https://web.archive.org/web/20121121033153/http://www.calcatraz.com/blog/php-topological-sort-function-384