Fix default values not being properly loaded for ArraySerialized fields

[mimarcel]

Preconditions:

• have latest M2.1 installed
• install demo data (using bin/magento demodata installation options)
• clean browser cookies for the domain you're at (to make sure we start from clean slate)
• make sure that you start with clean cache

Bug:
Default values are not properly loaded for fields with backend model \Magento\Config\Model\Config\Backend\Serialized\ArraySerialized.

How to replicate:

• Add system config field with backend Magento\Config\Model\Config\Backend\Serialized\ArraySerialized.

Example system.xml:

<?xml version="1.0"?>
<!--
 Copyright © 2009-2016 Vaimo AB. All rights reserved.
 See LICENSE.txt for license details.
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Config:etc/system_file.xsd">
    <system>
        <tab id="import_export" translate="label" sortOrder="1000">
            <label>Import Export</label>
        </tab>
        <section id="export" translate="label" type="text" sortOrder="1" showInDefault="1" showInWebsite="1" showInStore="1">
            <label>Export</label>
            <tab>import_export</tab>
            <resource>Vaimo_HellyHansenImportExport::config</resource>
            <group id="product_export" translate="label" type="text" sortOrder="1000" showInDefault="1" showInWebsite="1" showInStore="1">
                <label>Product Export</label>
                <field id="remove_export_columns" translate="label" type="text" sortOrder="1" showInDefault="1" showInWebsite="0" showInStore="0">
                    <label>Remove Export Columns</label>
                    <frontend_model>Vaimo\HellyHansenImportExport\Block\System\Config\Form\Field\Columns</frontend_model>
                    <backend_model>Magento\Config\Model\Config\Backend\Serialized\ArraySerialized</backend_model>
                    <comment>These columns will not be exported in Product Export.</comment>
                </field>
            </group>
        </section>
    </system>
</config>

• In order to make this work, we need to add the resource for it.

Example acl.xml:

<?xml version="1.0"?>
<!--
 Copyright © 2009-2016 Vaimo AB. All rights reserved.
 See LICENSE.txt for license details.
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Acl/etc/acl.xsd">
    <acl>
        <resources>
            <resource id="Magento_Backend::admin">
                <resource id="Magento_Backend::stores">
                    <resource id="Magento_Backend::stores_settings">
                        <resource id="Magento_Config::config">
                            <resource id="Vaimo_HellyHansenImportExport::config" title="Helly Hansen Import Export" sortOrder="50" />
                        </resource>
                    </resource>
                </resource>
            </resource>
        </resources>
    </acl>
</config>

• and also the frontend model:

<?php
/**
 * Copyright © 2009-2016 Vaimo AB. All rights reserved.
 * See LICENSE.txt for license details.
 */

namespace Vaimo\HellyHansenImportExport\Block\System\Config\Form\Field;

/**
 * Backend system config array field renderer
 *
 * @package Vaimo\HellyHansenItemExport\Block\System\Config\Form\Field
 */
class Columns extends \Magento\Config\Block\System\Config\Form\Field\FieldArray\AbstractFieldArray
{
    /**
     * Initialise form fields.
     *
     * @return void
     */
    protected function _construct()
    {
        $this->addColumn('column', ['label' => __('Column')]);
        $this->_addAfter = false;
        parent::_construct();
    }
}

• Add default value in config.xml.

Example:

<?xml version="1.0"?>
<!--
 Copyright © 2009-2016 Vaimo AB. All rights reserved.
 See LICENSE.txt for license details.
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Store:etc/config.xsd">
    <default>
        <export>
            <product_export>
                <!--Remove image-related and bundle-related columns from export.-->
                <remove_export_columns><![CDATA[a:15:{i:0;a:1:{s:6:"column";s:10:"base_image";}i:1;a:1:{s:6:"column";s:16:"base_image_label";}i:2;a:1:{s:6:"column";s:11:"small_image";}i:3;a:1:{s:6:"column";s:17:"small_image_label";}i:4;a:1:{s:6:"column";s:15:"thumbnail_image";}i:5;a:1:{s:6:"column";s:21:"thumbnail_image_label";}i:6;a:1:{s:6:"column";s:12:"swatch_image";}i:7;a:1:{s:6:"column";s:18:"swatch_image_label";}i:8;a:1:{s:6:"column";s:17:"additional_images";}i:9;a:1:{s:6:"column";s:23:"additional_image_labels";}i:10;a:1:{s:6:"column";s:17:"bundle_price_type";}i:11;a:1:{s:6:"column";s:15:"bundle_sku_type";}i:12;a:1:{s:6:"column";s:17:"bundle_price_view";}i:13;a:1:{s:6:"column";s:18:"bundle_weight_type";}i:14;a:1:{s:6:"column";s:13:"bundle_values";}}]]></remove_export_columns>
            </product_export>
        </export>
    </default>
</config>

• Go to admin and open STORES -> Configuration -> IMPORT EXPORT -> Export:

Expected: default value is loaded

Actual: default value is missing because afterLoad was not called on backend model when configuration existed ONLY as default value in config.xml

Notes:

• This issue was injected in Bug - Blank value for field type password/obscure when switching store view in store config #3019 and all what it does is reverting the code merged by Fix for issue #3019 (blank password/obscure field) #3020.

[magento-cicd2]

All committers have signed the CLA.

[skovalenk]

Hi @mimarcel

We watch on this code from another side:

1. backend model processing cant be applied in all scenarios (because in some scenarios already unserialized data can come on backend model)
2. We have one mechanism of getting configs. And this mechanism is \Magento\Framework\App\Config::class . This class allows to process backend models only one time
3. We dont want to process backend models in blocks. Blocks shouldnt know anything about backend models

This amendments will allow to use serialized data in config.xml file or in another source.

Thanks, Sergii

[mimarcel]

@sereban in which Magento version will the new fix be included?

[maghamed]

@mimarcel please look how this implemented in 2.2
https://github.com/magento/magento2/blob/develop/app/code/Magento/Config/Block/System/Config/Form.php#L413

It should meet your needs

[ghost]

@maghamed the issue persists in 2.2, as described in Steps to Replicate.
The block of code

         if ($field->hasBackendModel()) {
             $backendModel = $field->getBackendModel();
             $backendModel->setPath($path)
                 ->setValue($data)
                 ->setWebsite($this->getWebsiteCode())
                 ->setStore($this->getStoreCode())
                 ->afterLoad();
             $data = $backendModel->getValue();
         }

is not called when configuration value is taken from config.xml directly.

[viktym]

@marcel-moldovan-vm @mimarcel you should define backend model in config.xml

<?xml version="1.0"?>
<!--
 Copyright © 2009-2016 Vaimo AB. All rights reserved.
 See LICENSE.txt for license details.
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Store:etc/config.xsd">
    <default>
        <export>
            <product_export>
                <!--Remove image-related and bundle-related columns from export.-->
                <remove_export_columns backend_model="Magento\Config\Model\Config\Backend\Serialized"><![CDATA[.....}}]]></remove_export_columns>
            </product_export>
        </export>
    </default>
</config>

Magento\Config\Model\Config\Backend\Serialized should implement \Magento\Framework\App\Config\Data\ProcessorInterface (will be in 2.2.1)

[mimarcel]

@viktym setting the backend model in config.xml is a good hint, but it does not fix the issue.

[vkublytskyi]

@mimarcel please check 86d46ce and 6c9a8b2. With these changes serialized config data should be properly displayed at Admin Panel. But to use persisted config value it should be deserialized as scope config will return serialized string.

We can not modify such behavior of serialized config data due to backward compatibility.
To resolve this issue nicely in your extension you may:

1. Create Config class that will be a facade to config values declared by your module (like \Magento\Braintree\Gateway\Config\Config)
2. Create own config backend model which will implement Magento\Framework\App\Config\Data\ProcessorInterface and use this class instead of Magento\Config\Model\Config\Backend\Serialized

Please note that now changes available only in 2.2, 2.2-develop, 2.2.2-develop branches and included only in Magento 2.2.1 release.

If this approach suitable for you we will be thankful for a backporting solution to 2.1-develop branch. If you still have an issue with serialized config data please provide us more information what exact issue still present in Magento 2.2.1

[vkublytskyi]

@mimarcel I close this PR as the issue should be already fixed in Magento 2.2 and code change from PR will lead to #3019. Feel free to reopen it or create new PR if issue is still not fixed