Fix issue with di.xml config merging for classes array argument in case of different sources and the class name difference in leading slash.

[swnsma]

Description

PR to fix the reasons of #20410 (issue #20409).
During research I have discovered bug in config merging from di.xml.
Merging of nested arguments (array) in case of difference in class name (leading slash) in different files can leads to config lost.

Fixed Issues (if relevant)

1. Magento\Catalog\Api\ProductRenderListInterface returns products regardless of visibility #20409
2. Types not merged for etc/di.xml etc/adminhtml/di.xml #21193

Manual testing scenarios

Pre-Conditions

1. Change constructor of \Magento\Cms\Controller\Index\Index and add new argument 'data' (simple way to visualize it):

public function __construct(`
`        Context $context,`
        ForwardFactory $resultForwardFactory,
        ScopeConfigInterface $scopeConfig = null,
        Page $page = null,
        array $data = []
    ) {
        var_dump($data);
        die;
    }

Steps to reproduce

1. Create module A and B with simple config set (registration.php and module.xml).
2. Execute in terminal php bin/magento setup:upgrade.
3. Create etc/di.xml for module A:

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="Magento\Cms\Controller\Index\Index">
        <arguments>
            <argument name="data" xsi:type="array">
                <item name="p1" xsi:type="string">Hello Phrase1</item>
            </argument>
        </arguments>
    </type>
</config>

4. Create etc/di.xml for module B:

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="\Magento\Cms\Controller\Index\Index">
        <arguments>
            <argument name="data" xsi:type="array">
                <item name="p2" xsi:type="string">Hello Phrase2</item>
            </argument>
        </arguments>
    </type>
</config>

5. Execute in terminal php bin/magento cache:flush
6. Open home page.

Expected results

Actual results

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-engcom-team]

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[dominicfernando]

@swnsma

\ making the problem. But I think you try to solve \ problem.

<type name="\Magento\Cms\Controller\Index\Index"> <arguments> <argument name="data" xsi:type="array"> <item name="p2" xsi:type="string">Hello Phrase2</item> </argument> </arguments> </type>

[magento-engcom-team]

Hi @sivaschenko, thank you for the review.
ENGCOM-4094 has been created to process this Pull Request

[swnsma]

@dominicfernando
Yes.
There only difference for now is during array arguments merge :)

[Nazar65]

HI @swnsma your PR also fixes this issue -> #21193 your changes solves this

[swnsma]

Hi @Nazar65,
Thanks!

[ghost]

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[swnsma]

PR break Backward Compatibility due to merging of configs between general and concrete application level (e.g. adminhtml/frontend) leads to merging of configs (after changes in this PR) but not replacing of configs (before changes in this PR).