[2.4.4] Product with Salable Qty of 0 shows 'In Stock' on product page

[FadedOut]

FIX:
A quick non-official hack/fix was posted further below by @loic-paquin and @jas8522 here

Preconditions (*)

1. Upgraded from Magento 2.4.3-p1 to 2.4.4
2. Default Luma Theme or 3rd Party
3. Have backorders turned off (screenshot attached for confirmation that my settings are correct - though they did not change from 2.4.3-p1 where this was not a problem)

Steps to reproduce (*)

1. Have a product with 0 salable quantity (configurable product)
2. Go to frontend product page and check a variation/configuration (by selecting it)
3. You can click "Add to Cart"

Expected result (*)

1. It should say "Out of Stock" above SKU and/or you should not be able to select or click the variation swatch.
2. Should not be able to click "Add to Cart" for an "Out of Stock" product (with 0 salable qty).

Actual result (*)

1. It will allow you to click/select a swatch of an "out of stock" variation
2. It will say "In Stock"
3. Clicking "Add to Cart" it will reload page with error: "There are no source items with the in stock status"
4. The "X in Stock" feature (only X left threshold) shows correctly when it is under my threshold, but does not show on a product that is really out of stock (with selecting the variation). So that function knows not to show because there are 0 in stock.
5. Running re-index through CLI, I receive the following error (not sure if it's related - UPDATE: found this to not be related) and made no difference for this problem:

Product EAV index process error during indexation process: Deprecated Functionality: explode(): Passing null to parameter #2 ($string) of type string is deprecated in /home/********/public_html/vendor/magento/module-catalog/Model/ResourceModel/Product/Indexer/Eav/Source.php on line 444

My previous installation of 2.4.3-p1 that I just upgraded from, this worked as intended (out of stock variations could not be selected/clicked. It showed a cross-through of the variation that was out of stock). It now does not do this, after upgrading to 2.4.4.

Below are screenshots of the product page as well as the admin/backend showing 0 for default stock quantity. This example is shown on the stock Magento Luma theme.

EDIT/UPDATE:
The original report of EAV indexing (using CLI) failing might be related, was incorrect. It is not related and made no difference for the bug of "Product with Salable Qty of 0 shows 'In Stock' on product page" - they are separate issues.

Additional Information:
#35319 (comment)

---

Please provide Severity assessment for the Issue as Reporter. This information will help during Confirmation and Issue triage processes.

• Severity: S0 - Affects critical data or functionality and leaves users without workaround.
• Severity: S1 - Affects critical data or functionality and forces users to employ a workaround.
• Severity: S2 - Affects non-critical data or functionality and forces users to employ a workaround.
• Severity: S3 - Affects non-critical data or functionality and does not force users to employ a workaround.
• Severity: S4 - Affects aesthetics, professional look and feel, “quality” or “usability”.

[m2-assistant]

Hi @FadedOut. Thank you for your report.
To speed up processing of this issue, make sure that you provided the following information:

• Summary of the issue
• Information on your environment
• Steps to reproduce
• Expected and actual results

Make sure that the issue is reproducible on the vanilla Magento instance following Steps to reproduce. To deploy vanilla Magento instance on our environment, Add a comment to the issue:

@magento give me 2.4-develop instance - upcoming 2.4.x release

For more details, review the Magento Contributor Assistant documentation.

Add a comment to assign the issue: @magento I am working on this

To learn more about issue processing workflow, refer to the Code Contributions.

---

• Join Magento Community Engineering Slack and ask your questions in #github channel.

⚠️ According to the Magento Contribution requirements, all issues must go through the Community Contributions Triage process. Community Contributions Triage is a public meeting.

🕙 You can find the schedule on the Magento Community Calendar page.

📞 The triage of issues happens in the queue order. If you want to speed up the delivery of your contribution, join the Community Contributions Triage session to discuss the appropriate ticket.

✏️ Feel free to post questions/proposals/feedback related to the Community Contributions Triage process to the corresponding Slack Channel

[VZeroCool]

@magento give me 2.4-develop instance

[magento-deployment-service]

Hi @VZeroCool. Thank you for your request. I'm working on Magento instance for you.

[magento-deployment-service]

Hi @VZeroCool, unfortunately there is no ability to deploy Magento instance at the moment. Please try again later.

[m2-assistant]

Hi @engcom-November. Thank you for working on this issue.
In order to make sure that issue has enough information and ready for development, please read and check the following instruction: 👇

• 1. Verify that issue has all the required information. (Preconditions, Steps to reproduce, Expected result, Actual result).

  Details

  If the issue has a valid description, the label Issue: Format is valid will be added to the issue automatically. Please, edit issue description if needed, until label Issue: Format is valid appears.

• 2. Verify that issue has a meaningful description and provides enough information to reproduce the issue. If the report is valid, add Issue: Clear Description label to the issue by yourself.

• 3. Add Component: XXXXX label(s) to the ticket, indicating the components it may be related to.

• 4. Verify that the issue is reproducible on 2.4-develop branch

  Details

  - Add the comment @magento give me 2.4-develop instance to deploy test instance on Magento infrastructure.
  - If the issue is reproducible on 2.4-develop branch, please, add the label Reproduced on 2.4.x.
  - If the issue is not reproducible, add your comment that issue is not reproducible and close the issue and stop verification process here!

• 5. Add label Issue: Confirmed once verification is complete.

• 6. Make sure that automatic system confirms that report has been added to the backlog.

[engcom-November]

Hi @FadedOut , Thank you for reporting and collaboration.
Verified the issue on both Magento 2.4.3-p1 instance and 2.4.4 version after upgrading from 2.4.3-p1.
Observations:
Scenario 1: Existing Product - If Product Quantity is > 0 and Salable Quantity is 0 - User is able to select swatch and on clicking "Add to Cart" button - "The requested qty is not available" error message is displayed. Same behavior observed before and after upgrade

Scenario 2: Existing Product - If both Product Quantity & Salable Quantity = 0, User is not able to select swatch (Crossed out) in 2.4.3-p1 instance and "The requested qty is not available" error message is displayed in 2.4.4 version

Scenario 3: New Product created in 2.4.4 version with Product Quantity 0 - "There are no source items with the in stock status" error message is displayed
But re-indexing working fine in all cases.

2.4-develop branch behavior:

[engcom-November]

@magento give me 2.4-develop instance

[magento-deployment-service]

Hi @engcom-November. Thank you for your request. I'm working on Magento instance for you.

[magento-deployment-service]

Hi @engcom-November, unfortunately there is no ability to deploy Magento instance at the moment. Please try again later.