This allows the frontend to fetch data on the subscribers list (etc.)
for streams where the user has never been subscribed, making it
possible to implement UI showing details like subscribe counts on the
subscriptions page.
This is likely a performance regression for very large teams with
large numbers of streams; we'll want to do some testing to determine
the impact (and thus whether we should make this feature only fully
enabled for larger realms).
There were a bunch of authorization and well-formedness checks in
zerver.lib.actions.do_update_message that I moved to
zerver.views.messages.update_message_backend.
Reason: by convention, functions in actions.py complete their actions;
error checking should be done outside the file when possible.
Fixes: #1150.
This is controlled through the admin tab and a new field in the Realms table.
Notes:
* The admin tab setting takes a value in minutes, whereas the backend stores it
in seconds.
* This setting is unused when allow_message_editing is false.
* There is some generosity in how the limit is enforced. For instance, if the
user sees the hovering edit button, we ensure they have at least 5 seconds to
click it, and if the user gets to the message edit form, we ensure they have
at least 10 seconds to make the edit, by relaxing the limit.
* This commit also includes a countdown timer in the message edit form.
Resolves#903.
This is controlled through the admin tab and a new field in the Realms
table. This mirrors the behavior of the old hardcoded setting
feature_flags.disable_message_editing. Partially resolves#903.
The subscribers list is appended to in `peer_add` events with not
regard for preserving the ordering, and ordering isn't really
important here, so it seems best to just sort it in these checks.