Previously, users found it annoying that the automated "Resolve topic"
notifications triggered an unread for everyone in the stream; this
discouraged some users from using the feature on older threads for
fear of being annoying. We change this to a better default, of only
users who participated in the topic (via either messages or reactions)
being eligible for the new message being unread.
We will likely want to create global and stream-level notifications
settings to control this behavior as a follow-up -- some users, like
me, might prefer the simpler "Always unread" behavior in some streams.
Note that the automated notifications that a topic was resolved will
still result in the topic being moved to the top of the left sidebar.
This would be somewhat difficult to change, since the left sidebar
algorithm just looks at the highest message ID in the topic.
Fixes#19709.
Tests added by Aman Agrawal (amanagr@zulip.com).
This better matches the title of the page and more generally our
conventions around naming /help/ articles. We include a redirect
because this is referenced from Welcome Bot messages, and we
definitely don't want those links to break.
Tim Abbott
Damian Parrino