Description: The Mentions notification is an alert provided by the [[ https://www.mediawiki.org/wiki/Extension:Echo | echo extension ]] that occurs when your username is mentioned by someone else, with a link on any talk page (other than yours). This notification is already turned on by default on every Wikimedia user page. However, if a user wants to get notified about the success or failure of every user he or she has mentioned, the user can do so in the [[ https://www.mediawiki.org/wiki/Special:Preferences#mw-prefsection-echo | preference]] section.
I changed my preferences [[ https://www.mediawiki.org/wiki/Special:Preferences#mw-prefsection-echo | here]] because I wanted to get notified on every successful and failed mentions, created a new account for testing purposes and mentioned the newly created username in my original MediaWiki page.
Bug: ** The mentions worked successfully but I didn't get notified about its success as the sender even though I had changed my preferences to allow this feature of receiving notifications on every successful or failed mentions I send**. The notification documentation [[https://www.mediawiki.org/wiki/Help:Notifications/Notifications_types#Failed%20mentions | here ]] clearly states that a user is supposed to receive a notification of a failed mention if a mention to another user was not sent and described what can cause a failed mention. Example, if you try to mention a user that does not exist, or you exceed the limit of mentioned users in a single edit (50 on WMF wikis), the mention will not be sent. I tried mentioning a user that doesn't exist on my talk page (this means it wasnt sent) but I didn't get notified about the failure.
In summary, yes the mentions notification itself works, but the users who send the mention are supposed to be notified about its success or failures.
**Steps to Reproduce: **
- Go to https://www.mediawiki.org or https://en.wikipedia.org
- Make sure you are logged in;
- Click on [[ https://www.mediawiki.org/wiki/Special:Preferences | Preferences ]]
- Go to [[ https://www.mediawiki.org/wiki/Special:Preferences#mw-prefsection-echo | notifications]] and select "Succesful Mention" and "Failed Mention" from box list;
- Click the "Save" button.
- Mention a username in your talk page or in an edit summary.
**Actual Results: **
- You will not get notified about the success or failure.
**Expected Results: **
- You should've been notified about the success or failure.