When creating multiple streams using "POST /users/me/subscriptions"
endpoint, same anonymous group was being used for settings of all
the streams, like if can_subscribe_group was being set to an
anonymous group, all streams created using that endpoint would
use the same anonymous group for can_subscribe_group setting.
Using the same anonymous groups for multiple streams caused
unintended behavior -
- Changing a setting for one stream also changed it for all
other streams sharing the the same anonymous group, because
eventually the members and subgroups of the group were updated.
- Changing the setting to a named user group failed because
`do_change_stream_permission_group` attempts to delete the
anonymous group during the update. However, deletion of
anonymous group is restricted if they are still referenced
by setting fields.
This commit fixes this so that one anonymous group is used
only for one setting for a single stream.
For get and filter queries of NamedUserGroup, realm_for_sharding
field is used instead of realm field, as directly using
realm_for_sharding field on NamedUserGroup makes the query faster
than using realm present on the base UserGroup table.
Anonymous groups were being created for stream permission
settings when calling the subscriptions endpoint without
any streams data or when calling it only for subscribing
users to streams and not for creating any new streams.
This commit makes sure that no such unused anonymous groups
are created.
This commit renames `stream_creator_or_nobody` value for
`default_group_name` field in `server_supported_permission_settings`
object to `channel_creator`.
Removes send_new_subscription_messages parameter from
`POST channel/create` endpoint as Notification Bot DMs
are never sent when users are subscribed as part of
creating a new channel.
Not considered a documentable API change, since the previous parameter
never had any effect, so this is effectively just a documentation and
error-handling bug fix, not an API change relevant to implementors.
When a user is added to a channel, we send
the user that was added a Notification Bot
DMs to let them know about it.
In this commit, we add an option for whether or not
this message is sent.
If more than 100 users are added at once, we
do not send notification bot DMs since it would
be a performance-costly operation.
We also send this threshold value of 100 in the
initial state data to the clients.
Fixes part of #31189
