What is the right(official) way to programmatically add product attribute option in M2?
E.g. for manufacturer product attribute. Obviously existing option would be matched by "Admin" title value.

Here's the approach I've come up with for handling attribute options. Helper class:

<?php
namespace MyModuleHelper;

class Data extends MagentoFrameworkAppHelperAbstractHelper
false
 */
 public function getOptionId($attributeCode, $label, $force = false)
 !isset($this->attributeValues[ $attribute->getAttributeId() ])) 
 $this->attributeValues[ $attribute->getAttributeId() ] = [];

 // We have to generate a new sourceModel instance each time through to prevent it from
 // referencing its _options cache. No other way to get it to pick up newly-added values.

 /** @var MagentoEavModelEntityAttributeSourceTable $sourceModel */
 $sourceModel = $this->tableFactory->create();
 $sourceModel->setAttribute($attribute);

 foreach ($sourceModel->getAllOptions() as $option) 
 $this->attributeValues[ $attribute->getAttributeId() ][ $option['label'] ] = $option['value'];
 
 

 // Return option ID if exists
 if (isset($this->attributeValues[ $attribute->getAttributeId() ][ $label ])) 
 return $this->attributeValues[ $attribute->getAttributeId() ][ $label ];
 

 // Return false if does not exist
 return false;
 

Then, either in the same class or including it via dependency injection, you can add or get your option ID by calling createOrGetId($attributeCode, $label).

For example, if you inject MyModuleHelperData as $this->moduleHelper, then you can call:

$manufacturerId = $this->moduleHelper->createOrGetId('manufacturer', 'ABC Corp');

If 'ABC Corp' is an existing manufacturer, it will pull the ID. If not, it will add it.

UPDATED 2016-09-09: Per Ruud N., the original solution used CatalogSetup, which resulted in a bug starting in Magento 2.1. This revised solution bypasses that model, creating the option and label explicitly. It should work on 2.0+.

Using the MagentoEavSetupEavSetupFactory or even the MagentoCatalogSetupCategorySetupFactory class may lead to the following problem: https://github.com/magento/magento2/issues/4896.

The classes you should use:

protected $_logger;

protected $_attributeRepository;

protected $_attributeOptionManagement;

protected $_option;

protected $_attributeOptionLabel;

 public function __construct(
 PsrLogLoggerInterface $logger,
 MagentoEavModelAttributeRepository $attributeRepository,
 MagentoEavApiAttributeOptionManagementInterface $attributeOptionManagement,
 MagentoEavApiDataAttributeOptionLabelInterface $attributeOptionLabel,
 MagentoEavModelEntityAttributeOption $option
 )
 $this->_logger = $logger;
 $this->_attributeRepository = $attributeRepository;
 $this->_attributeOptionManagement = $attributeOptionManagement;
 $this->_option = $option;
 $this->_attributeOptionLabel = $attributeOptionLabel;
 

Then in your function do something like this:

 $attribute_id = $this->_attributeRepository->get('catalog_product', 'your_attribute')->getAttributeId();
$options = $this->_attributeOptionManagement->getItems('catalog_product', $attribute_id);
/* if attribute option already exists, remove it */
foreach($options as $option) 
 if ($option->getLabel() == $oldname) 
 $this->_attributeOptionManagement->delete('catalog_product', $attribute_id, $option->getValue());
 


/* new attribute option */
 $this->_option->setValue($name);
 $this->_attributeOptionLabel->setStoreId(0);
 $this->_attributeOptionLabel->setLabel($name);
 $this->_option->setLabel($this->_attributeOptionLabel);
 $this->_option->setStoreLabels([$this->_attributeOptionLabel]);
 $this->_option->setSortOrder(0);
 $this->_option->setIsDefault(false);
 $this->_attributeOptionManagement->add('catalog_product', $attribute_id, $this->_option);

tested on Magento 2.1.3.

I didn't find any workable way how to create attribute with options at once. So initially we need to create an attribute and then add options for it.

Inject following class MagentoEavSetupEavSetupFactory

 $setup->startSetup();

 /** @var MagentoEavSetupEavSetup $eavSetup */
 $eavSetup = $this->eavSetupFactory->create(['setup' => $setup]);

Create new attribute:

$eavSetup->addAttribute(
 'catalog_product',
 $attributeCode,
 [
 'type' => 'varchar',
 'input' => 'select',
 'required' => false,
 ...
 ],
);

Add custom options.

Function addAttribute doesn't return anything useful which can be used in future. So after attribute creation we need to retrieve attribute object by ourself. !!!Important We need it because function expects only attribute_id, but don't want to work with attribute_code.

In that case we need to get attribute_id and pass it to attribute creation function.

$attributeId = $eavSetup->getAttributeId('catalog_product', 'attribute_code');

Then we need to generate options array in the way magento expects:

$options = [
 'values' => [
 'sort_order1' => 'title1',
 'sort_order2' => 'title2',
 'sort_order3' => 'title3',
 ],
 'attribute_id' => 'some_id',
];

As example:

$options = [
 'values' => [
 '1' => 'Red',
 '2' => 'Yellow',
 '3' => 'Green',
 ],
 'attribute_id' => '32',
];

And pass it to function:

$eavSetup->addAttributeOption($options);

This is NOT an answer. Just a workaround.

It assumes that you have access to Magento Backend using browser and you are on the edit attribute page (url looks like admin/catalog/product_attribute/edit/attribute_id/XXX/key..)

Go to Browser console (CTRL + SHIFT + J on chrome)
and paste the following code after changing the array mimim.

$jq=new jQuery.noConflict();
var mimim=["xxx","yyy","VALUES TO BE ADDED"];
$jq.each(mimim,function(a,b)
$jq("#add_new_option_button").click();
$jq("#manage-options-panel tbody tr:last-child td:nth-child(3) input").val(b);
);

-- tested on Magento 2.2.2

Detailed article - https://tutes.in/how-to-manage-magento-2-product-attribute-values-options-using-console/