Magneto 2.3 Fix Product::addImageToMediaGallery throws Exception

[gelanivishal]

Original Pull Request

#18951

Fixed Issues (if relevant)

1. Product::addImageToMediaGallery throws Exception #6803: Product::addImageToMediaGallery throws Exception

Preconditions

Magento Version 2.2.6
PHP Version 7.1

Steps to reproduce

$product = $this->productFactory->create()
            ->setName($productName)
            ->setStatus($productStatus)
            ->setSku($productSku)
$product->setAttributeSetId($product->getDefaultAttributeSetId());

$product->addImageToMediaGallery($file, [
                'image',
                'small_image',
                'thumbnail',
            ], false, false);
$this->productRepository->save($product);

Expected result

Image gets added

Actual result

Exception gets thrown:

Notice: Undefined index: media_type in vendor/magento/module-catalog/Model/Product.php on line 2527

There's a workaround for this issue, using the Product::save method instead of the ProductRepositoryInterface::save method, but because it's a deprecated method I would like to avoid this.

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]

Hi @gelanivishal. Thank you for your contribution
Here is some useful tips how you can test your changes using Magento test environment.
Add the comment under your pull request to deploy test or vanilla Magento instance:

• @magento-engcom-team give me test instance - deploy test instance based on PR changes
• @magento-engcom-team give me 2.3-develop instance - deploy vanilla Magento instance

For more details, please, review the Magento Contributor Assistant documentation

[sivaschenko]

Changes to app/code/Magento/Catalog/Model/Product/Gallery/Processor.php and dev/tests/integration/testsuite/Magento/Catalog/_files/product_simple_with_image.php are already present in 2.3-develop

[magento-engcom-team]

Hi @sivaschenko, thank you for the review.
ENGCOM-3545 has been created to process this Pull Request

[orlangur]

@gelanivishal please pay attention to what you're porting, these changes already delivered in #18952.

[csdougliss]

@orlangur when is 2.3.1 released? I need this fixed.