How to implement a Customer custom attribute using EAV?

Question

Scenario

I'm trying to implement a custom attribute for Magento Customer, that should accept boolean values (True/False, Yes/No...).
I'm using Magento CE 2.2.4.
This is part of a custom Module under /app/code/TheVendor_TheModule/.
The other components of the Module are working correctly.

---

Expected Result

• The attribute must be represented with a switch input or checkbox in back-end Customer form.
• The attribute and its values must appear in Customers Grid
• The attribute must appear in the Filter with selectable options (Yes/No or True/False or Is/Is not, any Boolean-like value works fine)

---

Actual Result

• [OK] A switch shows in the back-end within the Customer form as expected.
• [OK] Changing the switch value to on or off + saving works fine.
• [Issue] The attribute's Label shows in the Customer Grid but the values are missing.
• [Issue] The attribute's input in the Filter shows but does not contain options.

---

Screens

Customer Form View in back-end

Customer Grid and Filter View

---

Code

Content of app/code/TheVendor/TheModule/Setup/InstallData.php

<?php

namespace TheVendor\TheModule\Setup;

use Magento\Customer\Setup\CustomerSetupFactory;
use Magento\Eav\Setup\EavSetup;
use Magento\Eav\Model\Config;
use Magento\Eav\Setup\EavSetupFactory;
use Magento\Framework\Setup\InstallDataInterface;
use Magento\Framework\Setup\ModuleContextInterface;
use Magento\Framework\Setup\ModuleDataSetupInterface;

class InstallData implements InstallDataInterface {

    const ATTRIBUTE_APPROVED = 'attribute_approved';

    protected $customerSetupFactory;

    private $eavSetupFactory;
    private $eavConfig;
    private $attributeResource;

    public function __construct(
        CustomerSetupFactory $customerSetupFactory, 
        EavSetupFactory $eavSetupFactory, 
        Config $eavConfig, 
        \Magento\Customer\Model\ResourceModel\Attribute $attributeResource
    ){
        $this->eavSetupFactory = $eavSetupFactory;
        $this->eavConfig = $eavConfig;
        $this->customerSetupFactory = $customerSetupFactory;
        $this->attributeResource = $attributeResource;
    }

    public function install(ModuleDataSetupInterface $setup, ModuleContextInterface $context)
    {
        $setup->startSetup();

        /** @var CustomerSetup $customerSetup */
        $customerSetup = $this->customerSetupFactory->create(['setup' => $setup]);

        $customerSetup->addAttribute(\Magento\Customer\Model\Customer::ENTITY, self::ATTRIBUTE_APPROVED, [
            'type' => 'int',
            'label' => 'Attribute Approved',
            'input' => 'boolean',
            'required' => false,
            'visible' => true,
            'system' => false,
            'position' => 9,
            'sort_order' => 9,
            'is_used_in_grid' => true,
            'is_visible_in_grid' => true,
            'is_filterable_in_grid' => true,
            'is_searchable_in_grid' => true,
            //'user_defined' => true, //commented because causing attribute fail on module install
            //'searchable' => true,
            'filterable' => true,
            'comparable' => true,
            'default' => '0',
            //'unique' => 0,
        ]);

        $myAttribute = $customerSetup->getEavConfig()->getAttribute(\Magento\Customer\Model\Customer::ENTITY, self::ATTRIBUTE_APPROVED);

        $myAttribute->setData('used_in_forms', ['adminhtml_customer']);

        $this->attributeResource->save($myAttribute);

        $setup->endSetup();

    }
}

---

Attempts and Tests

I tried the following:

• Lookup solution in Magento Dev Docs
• Lookup solution on StackExchange
• Lookup solution on other forums
• Tweaking $customerSetup->addAttribute(...) options:
  • Set 'user_defined' => true. When used, this one is causing the attribute setup to fail without errors.
  • Set 'default' => 0 and 'default' => '0'
  • Set 'searchable' => true
• Checked logs for errors, none found.
• Removed the Module folder and create it again before reinstall
• Executed php bin/magento setup:di:compile
• Executed php bin/magento setup:static-content:deploy -f

Testing Routine

For every test that I made I followed these steps to ensure Module is being installed correctly:

• Execute php bin/magento module:disable TheVendor_TheModule
• Remove records from database:
  • Delete Module record in mage_setup_module
  • Delete EAV record in mage_eav_attribute
• Make sure Module is disabled in app/etc/config.php
• Pull updated code
• Execute php bin/magento module:enable TheVendor_TheModule
• Execute php bin/magento setup:upgrade
• Execute php bin/magento indexer:reindex
• Execute php bin/magento cache:clean

---

Question

Anyone with suggestions on how to handle this or how to detect where the problem is coming from?

Answer 1

Problem Solved

Solution:

Edit addAttribute(...) options in app/code/TheVendor/TheModule/Setup/InstallData.php

Use source model 'Magento\Eav\Model\Entity\Attribute\Source\Boolean' with input select

...

$customerSetup->addAttribute(\Magento\Customer\Model\Customer::ENTITY, self::ATTRIBUTE_APPROVED, [
        'type' => 'int',
        'label' => 'Attribute Approved',

        /** [Solution] Changed from 'boolean' to 'select' */
        'input' => 'select',  

        /** [Solution] Use source model Boolean */
        'source' => 'Magento\Eav\Model\Entity\Attribute\Source\Boolean', 

        'default' => '0',
        'required' => false,
        'visible' => true,
        'system' => false,
        'position' => 9,
        'sort_order' => 9,
        //'user_defined' => true,
        //'searchable' => true,
        'filterable' => true,
        'comparable' => true,
        'is_used_in_grid' => true,
        'is_visible_in_grid' => true,
        'is_filterable_in_grid' => true,
        'is_searchable_in_grid' => true,
        //'unique' => 0,
   ]); 

...

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Screen

Hope this helps!