**Task**: As a user:** If at least one mention failed after a save, I want to see all mention info about one page change in one notificationsend the editor a notification including the failure reasons.
The notification should have the form of "Your mentions of AA, BB, CC on <page name> were sent out. The mentions to DD and EE failed due to <reason>, the mention to FF failed due to <reason>".**Failure reasons to be covered:**
- user has mentioned more than 50 users at once
- user name does not exist
- mention of anonymous user
- mention on the mentioned user’s page
- mention to self
Mockup: <TODO>
**Background**: On the German speaking Community Wishlist, it was proposed to be notified which mentions were sent out (as there are multiple reasons why they sometimes do not get sent out). This proposal received 22 points (#9) in the German Community Wishlist[1]. In addition to successful mentions, we figured that it might also make sense to report back, why unsuccessful mentions were not sent.**Screenshots + concrete messages:**
To come
**Background:** This task is based on a wish that received 21 points (#9) in the German Community Wishlist[1]. Originally, the wish was to receive an information about the sent messages. To keep the number of notifications smaller, and to help people use mentions in a way that they are sent, the task informs about mention failures, and adds the reasons for the failure as well.
[1] Link to wish (in German): https://de.wikipedia.org/wiki/Wikipedia:Umfragen/Technische_W%C3%BCnsche_2015/Topw%C3%BCnsche#Bei_Speichern_Hinweis_.C3.BCber_abgegebene_Benachrichtigungen_.5BUmfrage_2015.5D
in English: https://meta.wikimedia.org/wiki/WMDE_Technical_Wishes#Notifications_about_failed_mentions