Update comments

This commit is contained in:
Erik Johnston 2019-02-27 13:06:10 +00:00
parent 56f4ece778
commit b183fef9ac

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@ -836,12 +836,22 @@ class FederationHandler(BaseHandler):
#
# We do this by filtering all the extremities and seeing if any remain.
# Given we don't have the extremity events themselves, we need to
# actually check the events that references them.
# actually check the events that reference them.
#
# *Note*: the spec wants us to keep backfilling until we reach the start
# of the room in case we are allowed to see some of the history. However
# in practice that causes more issues than its worth, as a) its
# relatively rare for there to be any visible history and b) even when
# there is its often sufficiently long ago that clients would stop
# attempting to paginate before backfill reached the visible history.
#
# TODO: If we do do a backfill the we should filter the extremities to
# only include those that point to visible portions of history.
#
# TODO: Filter the list of extremities if we do do a backfill
# TODO: Correctly handle the case where we are allowed to see the
# forward event but not the extremity, e.g. in the case of initial
# join of the server.
# join of the server where we are allowed to see the join event but
# not anything before it.
forward_events = yield self.store.get_forward_events(
list(extremities),