Fixed #18812

[shikhamis11]

Fixed #18812 Unable to update simple product custom option in cart when quantity is 1

Preconditions (*)

1. Magento CE 2.2.5
2. Although reproduced in 2.2.2-2.2.4
3. Backorders disabled, minimum order qty is 1.
4. A simple product with at least one custom option, e.g. size - 1,2,3; price type fixed.

Steps to reproduce (*)

1. Go to product page and select options and click add to cart.
2. Go to cart and select "Edit/Update Item"
3. Select different option from original and click update.

Expected result (*)

1. Redirected back to cart
2. Product custom option updated.

Actual result (*)

1. Error message on product page.
   

Notes

It manifests as well if you have configurable product, where associated product has 1 stock, and configurable has custom option. Once selected and added to cart. If you try to update only custom option, the result is the same.

It appears that the code in Magento/Quote/Model/Quote.php#updateItem updates product item or adds new one if product item with matching custom/configurable options does not exist and later removes old item.
Problem is inside updateItem(), call to to addProduct() throws, because actual product qty is 1.

[m2-assistant]

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[dmytro-ch]

Hi @shikhamis11,
could you please check and fix the automated tests failures?

[dmytro-ch]

@shikhamis11, please note, the static need to be also fixed.
Once the changes are applied, please squash all commits into a single one in order to clean up history.
Thank you!

[Nazar65]

Hi @dmytro-ch please review.

[magento-engcom-team]

Hi @dmytro-ch, thank you for the review.
ENGCOM-5270 has been created to process this Pull Request

[makkoff]

✔️ QA Passed

[ghost]

@shikhamis11 unfortunately, only members of the maintainers team are allowed to unassign developers from the pull request

[sivaschenko]

Hi @shikhamis11 thanks for the pull request, I have several questions regarding this pull request, can you please take a look at my review comments

[sivaschenko]

Hi @shikhamis11 @dmytro-ch can you please provide an explanation on how this change is fixing the issue. Also, can you please explain the comment "we are using 0 because original qty was processed" - where the qty was processed?

As far as I remember \Magento\CatalogInventory\Model\Quote\Item\QuantityValidator\QuoteItemQtyList::getQty was working incorrectly becouse of null is passed as $quoteItemId in certain cases

[sidolov]

@shikhamis11 , I am closing this PR now due to inactivity.
Please reopen and update if you wish to continue.
Thank you for the collaboration!

[m2-assistant]

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