[Backport] Fix cache issue for currencies with no symbol

[dmytro-ch]

Original PR: #13894

Description

Using getCurrencySymbol() leads to a bug for currencies where there is no currency symbol - cache ends up being non-unique. Using currency code for caching is a more foolproof way.

The issue has been partially fixed by #13894. (\Magento\ConfigurableProduct\Block\Product\View\Type\Configurable)

Manual testing scenarios

1. Test the Catalog Category View page (including configurable products)
2. Test the Catalog Product List widget

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 @orlangur, thank you for the review.
ENGCOM-1847 has been created to process this Pull Request

[sidolov]

Hi @dmytro-ch , we found an issue in current implementation:

Price for configurable product isn't displayed correct on Product Detail Page.

Steps to reproduce:

Set Magento to use the following currency setup:
Base currency - USD
Default display currency - USD
Allowed currencies - Czech Republic Koruna, Danish Krone, US Dollar
Stores -> Currency rates should be set to the following:
USD/CZK rate: 20.8110
USD/DKK rate: 6.0967
Create configurable product with 1 product attached to it.
Set the price on the attached virtual product to $1 USD.
Visit configurable product page - you should see the default price of $1.
Select DKK in the currency-select box.

Expected result:
The price should change to 6.10.

Actual result:
Price DKK37.19 is displayed.

Notice. If you select the only product-option available, the price should change to 6.10.

[orlangur]

@sidolov as this PR is just a backport, did mentioned case worked fine on 2.2?

[sidolov]

@orlangur , yes, this case works on 2.2. Looks like in 2.2 release line additional fix was delivered in the scope of another task.

[dmytro-ch]

Hi @sidolov, thank you for the detailed way to reproduce.

I could also reproduce the issue in 2.1-develop branch.
Looks like the price for the configurable product is being calculated twice when there is no product option selected on product view page.
The related issue is #10150. Should it be reopened?

Thanks.

[orlangur]

Ping @sidolov :)

[sidolov]

Hi @dmytro-ch , I think if issue not reproducing in latest releases we should leave it closed. For 2.1 version the better way will be to found a complete fix for all cases, but it may be difficult to find it

[orlangur]

Closing due to inactivity. Feel free to reach me out anytime later if you wish to continue work on this pull request and it will be reopened.