Instantiating block by layout with xsi:object argument

[apiuser]

Feature request from zbych, posted on GitHub Apr 05, 2015

Getting following error: Instance of Magento\Framework\Data\CollectionDataSourceInterface is expected, got Some\Backend\Class\Of\Model\Defined\ByMe instead.

I am not sure if it is intended, if it is, and it is within the rules of core functionality, then please cancel this issue and sorry for bothering. I am just not sure if blocks can accept only objects that inherits the Collection interface.

[apiuser]

Comment from vpelipenko, posted on GitHub Apr 06, 2015

@zbych, what should we do to reproduce this issue?

[apiuser]

Comment from orlangur, posted on GitHub Apr 06, 2015

There is no need to inherit from some collection class I believe, but Some\Backend\Class\Of\Model\Defined\ByMe must implement Magento\Framework\Data\CollectionDataSourceInterface.

[apiuser]

Comment from tzyganu, posted on GitHub Apr 06, 2015

@orlangur What's the purpose of the CollectionDataSourceInterface interface? It does not contain any methods at the moment.

[apiuser]

Comment from zbych, posted on GitHub Apr 06, 2015

@vpelipenko I prepared a simple module for you that reproduces this issue: https://www.dropbox.com/s/gh9cuzp4jmcgmtn/verde_test.tar.gz?dl=0

See explanation in layout. I hope it will help.

Thanks!

[apiuser]

Comment from vkorotun, posted on GitHub Apr 06, 2015

There is an layout argument of object type (xsi:type="object") you can pass to blocks' constructors. It is configured in di.xml, like showed here:

<virtualType name="layoutObjectArgumentInterpreter" type="Magento\Framework\View\Layout\Argument\Interpreter\Object">
    <arguments>
        <argument name="expectedClass" xsi:type="string">Magento\Framework\Data\CollectionDataSourceInterface</argument>
    </arguments>
</virtualType>

Originally this type of argument was developed for Admin Widget Grids to allow passing Collections as an argument to Grid constructor and it had being restricted to "Magento\Framework\Data\Collection". After a while instead of that there was created an empty marking interface, so now you may pass some custom types of collections with more soft restriction - they all should implement this very CollectionDataSourceInterface.

I'd like to consider an ideas if we should remove any restriction for "object" argument type and allow passing any type of objects.

[apiuser]

Comment from zbych, posted on GitHub Apr 07, 2015

@vpelipenko FYI: Update of Verde/Test module. I made there a mistake, but issue still occurs. @vkorotun you are right. Sometimes there is a need to configure object from layout, to keep Block reusable. After searching for other occurrences of xsi:type="object" in Magento layouts I found only Backend blocks using Collections, so I assumed it as "rule". That's why I was just not sure if it is bug.

Thanks for considering for removing constraint for Collection in that place. I think that it should expand power of layout and blocks.

Thanks!

[apiuser]

Comment from vkorotun, posted on GitHub Aug 04, 2016

Internal ticket: MAGETWO-56369