Namely, annotate as best as possible, and add notes to indicate preference,
if QuerySet develops generic typing.
Note that the return values of functions with annotations changed in this
commit are used elsewhere as QuerySets, so the Sequence[T] approach used
for some functions in models.py is not applicable.
We extract get_bulk_stream_subscriber_info() from this
function to remove some of the complexity. Also, in that
new function we avoid a hop to the database by querying
on stream ids instead of recipient ids. The query that
gets changed here does require a join to the recipient
table (to get the stream id), so it's a little bit of a
tradeoff.
The first method we extract to this library is
get_active_subscriptions_for_stream_id().
We also move num_subscribers_for_stream_id() to here, which
is slightly annoying (having the method on Stream was nice)
but avoids some circular dependency issues.
neiljp (Neil Pilgrim)
rht
Steve Howell