Making a null edit (different from a dummy edit) to a certain user's talk page makes the user receive a notification that he has a new message although that the null edit itself is not recorded in the user talk page history.
Steps to reproduce:
- Logout of your account.
- While logged out make a null edit to your use talk page. (The null edit edit is not recorded in the user talk page history as expected.)
- Log in back to your account.
You receive a new message notification. When clicking on the notification link, you are redirected to the most recent diff on your talk page (which is not related to the null edit itself).
- MediaWiki should be consistent about what it does with null edits. Since null edits are not recorded in history and they don't appear in watchlists, then they shouldn't trigger a new message notification.
Tested using Google Chrome 47 under Windows 8 on Arabic Wikipedia (arwiki)