Pull Request for Issue #45470 .

Summary of Changes

fixes inconsistent behavior between the Joomla backend Interface and the Web Services (API) when creating an article with an alias that already exists in the same category.

Testing Instructions

• Ensure you have at least one category and an existing article within that category (e.g., an article with the alias "my-test-article" in the "Uncategorised" category).

• Use an API client (like Postman) or write a script to send a POST request to the /api/index.php/v1/content/articles endpoint.

• Send a JSON payload that will create a duplicate alias in the same category. For example:

{
  "title": "My Test Article",
  "alias": "my-test-article",
  "catid": 2,
  "articletext": "This is the article text.",
  "state": 1
}

Actual result BEFORE applying this Pull Request

the API returns a HTTP 400 error with the message: Save failed with the following error: Another Article in this category has the same alias.

Expected result AFTER applying this Pull Request

Verify that the new article has been created and its alias has been modified (e.g., to my-test-article-1).

Link to documentations

Please select:

• Documentation link for docs.joomla.org:

• No documentation changes for docs.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed