Magento2 - override 3rd party module layout file in custom theme

Question

We have a custom theme with some layout / template overrides

Now we have installed a 3rd party module, which is overriding one of layout files in our custom theme. So, only module's override is being loaded

I suppose, we can deal with this, by defining that concrete layout override in a custom module (instead of the custom theme approach), and then define the module dependencies to load both layout overrides

Or is there a way to do that without the need of declaring a new module?

UPDATE

About RishabhRkRai answer...

Let's say our custom theme is placed in folder app/design/frontend/Sinapsis/projectname

We had this layout override there:

app/design/frontend/Sinapsis/projectname/Magento_Multishipping/layout/multishipping_checkout_billing.xml

Now, we've installed a module which overrides that same layout file. The concrete module name is Df_Checkout, and problem is our layout override stopped working

I've tried, following the answer, moving our override to

app/design/frontend/Sinapsis/projectname/Df_Checkout/layout/multishipping_checkout_billing.xml

but only module's layout keeps loading

Answer 1

In your custom theme, follow this to override the layout file

app/design/frontend/Theme_Vendor/Theme_Name/ThirdPrty_Vendor/Module_Name/layout/file_to_override.xml

After doing this, remove the static files and flush the cache

1. rm -rf pub/static/*
2. php bin/magento setup:static-content:deploy
3. php bin/magento cache:flush

There is an alternate way, which may works for you. You just need to create an custom module and inside module.xml add the dependency like

    <?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
    <module name="Vendor_Modulename" setup_version="2.1.7">
        <sequence>
            <module name="ThirdParty_ModuleName"/>
        </sequence>
    </module>
</config>

Now you have to override the xml file as

app/code/Vendor/Module_Name/view/Scope/layout/file_to_override.xml

Answer 2

Please note that magento has 2 ways to customize layout.

Extend layout http://devdocs.magento.com/guides/v2.0/frontend-dev-guide/layouts/layout-extend.html

Override layout http://devdocs.magento.com/guides/v2.0/frontend-dev-guide/layouts/layout-override.html

Here are a few steps to make sure that your layout is extended correctly.

1. move layout in your theme

app/design/frontend/Sinapsis/projectname/Df_Checkout/layout/multishipping_checkout_billing.xml

2. Check the layout and make sure that block names match.

3. Check the code in your Block. There are cases when the template was updated directly in the block code. In that way you need to extend the Block.