sales.xsd

The new format for the sales.xml files moves both the instance and the sort order into the item node. Previously in Mage1 it was possible to change both the instance / sort order via an xml directive that got merged, for example:

<quote>
    <totals>
        <subtotal>
            <class>mySalesExtension/quote_address_total_subtotal</class>

The equivalent would not work in Magento2. Not sure if this currently an intended outcome to disallow this or an unintended consequence.

Subnodes are allowed in Mage2 to supply a different renderer like the Tax module currently does.

[antonkril]

Item name is an identifier attribute, so you should be able to modify both instance type and sort order.

Doesn't seem to work for me. If I use

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../Magento/Sales/etc/sales.xsd">
    <section name="quote">
        <group name="totals">
            <item name="test" instance="Fooman\Example\Model\Subtotal" sort_order="100"/>
        </group>
    </section>
</config>

I get

There has been an error processing your request

Class Fooman\Example\Model\Subtotal does not exist

which is the expected outcome.

However if I use if with the existing subtotal

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../Magento/Sales/etc/sales.xsd">
    <section name="quote">
        <group name="totals">
            <item name="subtotal" instance="Fooman\Example\Model\Subtotal" sort_order="100"/>
        </group>
    </section>
</config>

I would expect to see the same error message but it processes the cart normally.

It would also be great to have this consistent with the renderer (ie choose 1 approach)

[antonkril]

This can happen because original config overrides your because your module is loaded later.

Indeed when I move it to the end of the module declaration in config.php it works.

I did have

    <sequence>
        <module name="Magento_Sales"/>
    </sequence>

so it appears that the xml file loader for sales.xml files does not get sorted by sortBySequence the same as module.xml files do.

[antonkril]

Sales.xml reader uses standard configuration reader so it should be sorted in the same way as other files do.

app/etc/config.php is created by install script taking into account module dependencies so the list is sorted in specific way. And editing it manually to turn off/on modules might lead to problems that you encountered.

@antonkril the following statement is probably more correct: only the loading of module.xml files gets sorted by sequence see https://github.com/magento/magento2/blob/develop/lib/internal/Magento/Framework/Module/ModuleList/Loader.php#L61 all others are sorted the same way (order in config.php).

My expectation would have been that the sequence defined in module.xml is adhered to when loading sales.xml (or any other xml) which is not the case.

app/etc/config.php is created by install script taking into account module dependencies so the list is sorted in specific way. And editing it manually to turn off/on modules might lead to problems that you encountered.

Manually editing config.php is currently the only way to extend Magento so as long as there is no alternative for it it will be used.

[antonkril]

Sorting happens only once for module.xml, and sort order is then used for all configuration files. So sales.xml is loaded/merged in same order. See https://github.com/magento/magento2/blob/develop/lib/internal/Magento/Framework/Module/Dir/Reader.php#L78

You can use
php -f setup/index.php <module-enable|module-disable> --modules=Magento_Foo,Magento_Bar... [--force]
to enable/disable modules

@antonkril that's great to hear that this command is now available. Hopefully this gets a bit more exposure in the docs so that everyone knows how to use this going forward.