Pull Request resolves #48507

• I read the Generative AI policy and my contribution is either not created with the help of AI or is compatible with the policy and GNU/GPL 2 or later.

Summary of Changes

Updated the username validation in libraries/src/Table/User.php to reject whitespace characters anywhere in the username.

Previously, Joomla could accept usernames containing spaces, such as Ahmad Moussa. The validation now also checks for whitespace between characters, while keeping the existing validation for leading and trailing whitespace.

Examples:
"AhmadMoussa" → accepted
"Ahmad Moussa" → rejected
" AhmadMoussa" → rejected
"AhmadMoussa " → rejected

Testing Instructions

Create or edit a Joomla user and test the following usernames:

"AhmadMoussa"
"Ahmad Moussa"
" AhmadMoussa"
"AhmadMoussa "

Verify that usernames without whitespace are accepted and usernames containing whitespace are rejected.

Actual result BEFORE applying this Pull Request

Joomla allowed usernames containing spaces between words, such as "Ahmad Moussa".

Expected result AFTER applying this Pull Request

Joomla rejects usernames containing whitespace characters, including spaces between words and leading or trailing whitespace.

Link to documentations

Please select:

• Documentation link for guide.joomla.org:
• No documentation changes for guide.joomla.org needed
• Pull Request link for manual.joomla.org:
• No documentation changes for manual.joomla.org needed