Category product count does not include products assigned to the category itself

[mohaelmrabet]

Summary

This pull request fixes an issue where the product count displayed in the Admin Category Grid
incorrectly shows 0 products for categories that do not have any descendants.
The current logic only counts products assigned to descendant categories and does not
include products directly assigned to the category itself.

Problem

When building the temporary table of category → descendant relationships, the SQL
logic only inserts rows for descendants, not for the category itself.
As a result:

• Leaf categories always show 0 products
• Parent categories show incomplete counts
• The Admin UI becomes misleading for merchants

Related Issue
Fixes #40263

What This Fix Does

This change ensures that each category always includes a self-reference entry in
the temporary category/descendant table.
As a result:

• Products directly assigned to the category are counted correctly
• Categories without children no longer show a zero count
• Product assignment visibility in Admin becomes accurate

Technical Changes

• Added a self-reference row (category_id = X, descendant_id = X) for every
  processed category ID.
• Ensured that the final SQL aggregation counts products from both descendants
  and the category itself.
• Updated unit tests to validate multiple insert calls for self-references.

Testing Instructions

1. Create a category with no children.
2. Assign one or more products to it.
3. Clear cache and refresh the Category Grid.
4. Product count should now display the correct value instead of zero.
5. Repeat with nested categories to confirm descendant counts still work.

Backward Compatibility

• No schema changes.
• No API changes.
• Fully backward compatible.

Risks

Low. This affects only the temporary table generation used for counting, not
the category model or product relations.

[m2-assistant]

Hi @mimou78. Thank you for your contribution!
Here are some useful tips on how you can test your changes using Magento test environment.
❗ Automated tests can be triggered manually with an appropriate comment:

• @magento run all tests - run or re-run all required tests against the PR changes
• @magento run <test-build(s)> - run or re-run specific test build(s)
  For example: @magento run Unit Tests

<test-build(s)> is a comma-separated list of build names.

Allowed build names are:

1. Database Compare
2. Functional Tests CE
3. Functional Tests EE
4. Functional Tests B2B
5. Integration Tests
6. Magento Health Index
7. Sample Data Tests CE
8. Sample Data Tests EE
9. Sample Data Tests B2B
10. Static Tests
11. Unit Tests
12. WebAPI Tests
13. Semantic Version Checker

You can find more information about the builds here
ℹ️ Run only required test builds during development. Run all test builds before sending your pull request for review.

---

For more details, review the Code Contributions documentation.
Join Magento Community Engineering Slack and ask your questions in #github channel.

[ct-prd-pr-scan]

The security team has been informed about this pull request due to the presence of risky security keywords. For security vulnerability reports, please visit Adobe's vulnerability disclosure program on HackerOne or email psirt@adobe.com.

[ct-prd-pr-scan]

The security team has been informed about this pull request due to the presence of risky security keywords. For security vulnerability reports, please visit Adobe's vulnerability disclosure program on HackerOne or email psirt@adobe.com.

[mohaelmrabet]

@magento run all tests

[swnsma]

Thank you for your changes!
Could you have a look at my small note about unit tests?

[mohaelmrabet]

@magento run all tests

[mohaelmrabet]

Hi @mimou78,

Thank you for your changes!

It looks like the $addVisibilityFilter parameter was introduced to fetch product counts from the API while excluding products that do not have CATEGORY visibility.

You’re right that there is a discrepancy between fetching products that are in the index (which counts only visible products) and products outside the index (which count all products).

My suggestion is that we proceed with this PR as it is, since the issue already exists in the current implementation. However, your observation can be reported as a separate issue.

If you’d like to continue working on a potential fix for the visibility issue, I’d be happy to help and review your PR.

Hi,
Thanks for your feedback!

That's perfectly fine for me — I agree with proceeding with the PR as it is.
To track the visibility inconsistency separately, I’ve created a dedicated issue here: #40320

I’ll be happy to continue working on a potential fix for the visibility behavior, and I appreciate your support for reviewing the PR.

Thanks again!

[swnsma]

@magento run all tests

[mohaelmrabet]

@magento run Adobe CLA Signed?

[magento-automated-testing]

Failed to run the builds. Please try to re-run them later.

[mohaelmrabet]

@magento run all tests

[swnsma]

@magento run Functional Tests B2B,Functional Tests CE,Functional Tests EE

[swnsma]

@magento run Functional Tests B2B,Functional Tests CE,Functional Tests EE

[swnsma]

@magento run all tests

[swnsma]

@magento run all tests

[swnsma]

Broken tests do not related to the changes in the Pull Requests.

[engcom-Bravo]

@magento run all tests

[engcom-Bravo]

Hi @mohaelmrabet,

Thanks for the collaboration & contribution!

✔️ QA Passed

Preconditions:

• Install fresh Magento 2.4-develop

Steps to reproduce

• Create a category with no children.
• Assign one or more products to it.
• Clear cache and refresh the Category Grid.
• Product count should now display the correct value instead of zero.
• Repeat with nested categories to confirm descendant counts still work.

Before: ✖️ 

After: ✔️

Builds are failed. Hence, moving this PR to Extended Testing.

Thanks.