plugin XEP-0384, XEP-0391: download missing devices list: when a peer jid was not in our roster, devices list was not retrieved, resulting in failed en/decryption. This patch does check it and download missing devices list in necessary. There is no subscription managed yet, so the list won't be updated in case of new devices, this should be addressed at some point.

from typing import Optional

from twisted.words.xish import domish


class BaseError(Exception):
    namespace: str
    condition: str
    text: Optional[str]
    textLang: Optional[str]
    appCondition: Optional[domish.Element]

class StanzaError(BaseError):
    ...