MSC4242: State DAGs (serving) - #20133
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| class StateDag: | ||
| GET_MISSING_EVENTS_FIELD: Final = "org.matrix.msc4242.state_dag" | ||
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| MAX_MISSING_EVENTS: Final = 1000 |
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Why 1000?
If arbitrary, that's fine (comment)
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| if supports_msc4242_state_dag(event): | ||
| caller_supports_partial_state = False |
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Explain why (comment)
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| # Sort by depth, though this is just a nicety, MSC4242 does not require it | ||
| state_dag = sorted( | ||
| state_dag_map.values(), key=lambda ev: (ev.depth, ev.event_id) | ||
| ) |
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| if walk_state_dag: | ||
| return await self.on_get_missing_events_state_dag( | ||
| room_id, earliest_events, latest_events, limit | ||
| ) |
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Perhaps we should just raise this logic up one level
| if prev_state_event_id not in earliest_event_set | ||
| ) | ||
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| first_hop_event_ids.difference_update(seed_event_ids) |
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| create_event_ids = [ | ||
| ev | ||
| for ev in state_dag | ||
| if (ev["type"], ev["state_key"]) == ("m.room.create", "") | ||
| ] | ||
| self.assertEqual(len(create_event_ids), 1) |
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Why do we care about checking this?
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| @skip_test("requires MSC4242 inbound event auth") | ||
| @override_config({"experimental_features": {"msc4242_enabled": True}}) | ||
| def test_send_join_state_dag_ignores_partial_state(self) -> None: |
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Where in the test are we expecting to ignore partial state? (needs comment to point it out)
| ) | ||
| channel = self.make_signed_federation_request( | ||
| "PUT", | ||
| f"/_matrix/federation/v2/send_join/{room_id}/x?omit_members=true", |
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Comment about ?omit_members=true being the thing causing partial state, etc
| self.assertEqual(channel.code, HTTPStatus.OK, channel.json_body) | ||
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| event = channel.json_body["event"] | ||
| self.assertNotIn("auth_events", event) |
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| extremities = self.get_success( | ||
| self.hs.get_datastores().main.get_state_dag_extremities(room_id) | ||
| ) | ||
| self.assertGreater(len(extremities), 0) | ||
| self.assertCountEqual(event["prev_state_events"], extremities) | ||
| self.assertIncludes( | ||
| set(event["prev_state_events"]), set(extremities), exact=True | ||
| ) |
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Adds the serving functions needed for MSC4242: State DAGs. This PR adds MSC4242 support to /make_join, /send_join and /get_missing_events, as well as calculates the destinations for /send events correctly using
prev_state_events.Built on top of #19718 for the storage functions it makes.
Split out from #19425
Part of a series of 5x PRs to land the federation part of MSC4242 (storage, fedclient, serving (this PR), inbound-joins, inbound-pulls).
Whilst this is mostly a port of the code in #19425 there are a few changes:
/get_missing_eventsaccepts message events when walking the state DAG, in which case it resolves the first hop to be that event'sprev_state_events. The original PR made the client/eventthe message event and then setlatest=[prev_state_events]on its own. This is not very efficient (extra round trip to fetch the event) and there's no reason why the server can't do the message->prev_state_events lookup, so we do so. This matches the MSC examples./get_missing_events. The MSC allows it, so it's a good safety check./send_joinby depth then event ID so it's "mostly" sorted. This is more a formality than anything else, the MSC does not mandate this, but it makes/send_joinresponses deterministic.notify_on_event_delivered_over_federationis a new thing since MSC4242: State DAGs (Federation) #19425, so we include state DAG events in it like we do with state/auth_chain.This PR does remove the forced
m.federate: falsesetting for MSC4242 rooms, so it makes it possible for federated MSC4242 rooms to be made. This is mostly so we can test via the endpoints. Given you must opt-in to MSC4242 via the experimental features config option, it seems reasonable to loosen this setting. The forced no-federation flag existed prior to review saying that the MSC4242 room version could itself be gated behind an experimental feature.Reviewable commit-by-commit.
Pull Request Checklist
EventStoretoEventWorkerStore.".code blocks.