A fix for issue #9265

[evgk]

Fixes issue #9265

Description

This line: $quantity = $quantity ?: 1;
in ./vendor/magento/module-catalog/Pricing/Price/TierPrice.php, line 75,
uses the ternary shorthand operator to set the quantity to 1 when
the quantity that is passed can be converted to false.
At this point, the quantity comes from the SaleableInterface item - the simple product model itself.
Note that the type signature for the getQty method in SaleableInterface indicates that it should always
return a float:

/**

• Returns quantity of saleable item
• @return float
  */
  public function getQty();

However, on the grouped-product page this item comes from this collection:
./vendor/magento/module-catalog/Model/ResourceModel/Product/Link/Product/Collection.php
(a collection of linked products). So the quantity that is set in the product model comes from the
"Default quantity" field which is stored as an attribute of the link(catalog_product_link_attribute_decimal) -
however, since neither Magento nor the underlying Zend libraries have any conversion from the MySQL to PHP types when loading the collections,
and MySQL client/server communication is done via a text-based protocol, this "qty" field ends up being a string in PHP.
Thus, the getQty function will return a string representation of a decimal value("0.0000000") in a clear violation of the SaleableInterface, and it leads to this issue with the tier price above(since the ternary shorthand operator will treat "0.000000" string as true, not setting the quantity to 1 as a result).
Suggested fix does a forceful conversion of the link-attributes with type=decimal to a PHP float-value on the link-product-collection afterLoad event.
It is possible to do the same for the integer type as well, but doing it just for the type=decimal seems least intrusive, and it would solve this interface-mismatch and tier-price issue.

Fixed Issues (if relevant)

1. Tier price / grouped product issue #9265: Tier price / grouped product issue

Manual testing scenarios

1. ...
2. ...

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)

[evgk]

Hi,
I can see the PR wasn't processed in April. Do you need any additional information?

[ishakhsuvarov]

Hi @evgk
We have tried and could not reproduce the issue in question (#9265) on the latest code from the develop branch, may be it it specific to 2.1.x versions only?

[evgk]

Hi,
I have now tried to reproduce it on the latest codebase(before, I tested on 2.1.6) - and I can reproduce the bug. I'm attaching the screenshots.

root@manage /var/www/magento2/last_dev/magento2 # git log -n 1
commit bd22a2c
Merge: 397f87b 015424a
Author: Oleksii Korshenko okorshenko@magento.com
Date: Thu Jun 15 19:33:40 2017 -0500

Merge pull request #1201 from magento-engcom/develop-prs

Public Pull Requests

magento/magento2#9943
magento/magento2#9941

This is a screenshot of an incorrect product-page without the suggested fix:

This is a screenshot of a correct product page with the suggested fix applied:

Those are the settings for the grouped product:

Those are the settings for the test2 product:

Tier price for the test2 product:

Do you have the same settings when testing and do you see the same in frontend?

[evgk]

The "Default Quantity" field in the "Grouped Products" section on the grouped product should be 0

Please note that this is essential to reproduce the bug.