* FEATURE: Show warning if group cannot be mentioned
A similar warning is displayed when the user cannot be mentioned because
they have not been invited to the topic.
* FEATURE: Resolve mentions for new topic
This commit improves several improvements and refactors
/u/is_local_username route to a better /composer/mentions route that
can handle new topics too.
* FEATURE: Show warning if only some are notified
Sometimes users are still notified even if the group that was mentioned
was not invited to the message. This happens because its members were
invited directly or are members of other groups that were invited.
* DEV: Refactor _warnCannotSeeMention
* Introduced fab!, a helper that creates database state for a group
It's almost identical to let_it_be, except:
1. It creates a new object for each test by default,
2. You can disable it using PREFABRICATION=0
This change both speeds up specs (less strings to allocate) and helps catch
cases where methods in Discourse are mutating inputs.
Overall we will be migrating everything to use #frozen_string_literal: true
it will take a while, but this is the first and safest move in this direction
