Add type hints to synapse/storage/databases/main

[dklimpel]

Pull Request Checklist

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• Pull request includes a changelog file. The entry should:
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Signed-off-by: Dirk Klimpel [email protected]

[erikjohnston]

I'm not surprised, given the code as it stands is convoluted. TBH I'd be tempted to rewrite it as something like:

states = {}
for user_id in user_ids:
    state = self.user_to_current_state.get(user_id, None)
    if state:
        states[user_id] = state
    else:
        ...

[dklimpel]

Hopefully it's better now. The database query for a single user is not implemented _get_presence_for_user. My thoughts were that calling get_presence_for_users for every single user becomes a lot of overhead.
The loops are getting smaller now and perhaps increase the performance.

[erikjohnston]

I'd be sorely tempted to do a self._instance_name = hs.get_instance_name() at the top, even though it technically is redefines it

[dklimpel]

Suggested change

	if user_id not in res:
	if not res.get(user_id, None):

[erikjohnston]

Oh, bah. Sorry. Looks like get_presence_for_users returns None for missing users.