feat(hydra): Initial public commit for v12 support

# Conflicts:
#	src/core/info/room_version.rs
#	src/service/rooms/timeline/create.rs

Cargo.toml

@@ -352,7 +352,7 @@ version = "0.1.2"
 [workspace.dependencies.ruma]
 git = "https://forgejo.ellis.link/continuwuation/ruwuma"
 #branch = "conduwuit-changes"
-rev = "8fb268fa2771dfc3a1c8075ef1246e7c9a0a53fd"
+rev = "191e5c541e8339080bebb5ac6855a682330bb886"
 features = [
     "compat",
     "rand",

src/admin/user/commands.rs

@@ -756,7 +756,7 @@ pub(super) async fn force_demote(&self, user_id: String, room_id: OwnedRoomOrAli
 		.build_and_append_pdu(
 			PduBuilder::state(String::new(), &power_levels_content),
 			&user_id,
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.await?;
@@ -901,7 +901,13 @@ pub(super) async fn redact_event(&self, event_id: OwnedEventId) -> Result {
 	);
 
 	let redaction_event_id = {
-		let state_lock = self.services.rooms.state.mutex.lock(event.room_id()).await;
+		let state_lock = self
+			.services
+			.rooms
+			.state
+			.mutex
+			.lock(&event.room_id_or_hash())
+			.await;
 
 		self.services
 			.rooms
@@ -915,7 +921,7 @@ pub(super) async fn redact_event(&self, event_id: OwnedEventId) -> Result {
 					})
 				},
 				event.sender(),
-				event.room_id(),
+				Some(&event.room_id_or_hash()),
 				&state_lock,
 			)
 			.await?

src/api/client/account.rs

@@ -929,7 +929,7 @@ pub async fn full_user_deactivate(
 				.build_and_append_pdu(
 					PduBuilder::state(String::new(), &power_levels_content),
 					user_id,
-					room_id,
+					Some(room_id),
 					&state_lock,
 				)
 				.await

src/api/client/context.rs

@@ -69,7 +69,7 @@ pub(crate) async fn get_context_route(
 
 	let (base_id, base_pdu, visible) = try_join3(base_id, base_pdu, visible).await?;
 
-	if base_pdu.room_id != *room_id || base_pdu.event_id != *event_id {
+	if base_pdu.room_id_or_hash() != *room_id || base_pdu.event_id != *event_id {
 		return Err!(Request(NotFound("Base event not found.")));
 	}
 

src/api/client/membership/ban.rs

@@ -49,7 +49,7 @@ pub(crate) async fn ban_user_route(
 				..current_member_content
 			}),
 			sender_user,
-			&body.room_id,
+			Some(&body.room_id),
 			&state_lock,
 		)
 		.await?;

src/api/client/membership/invite.rs

@@ -128,12 +128,12 @@ pub(crate) async fn invite_helper(
 				.create_hash_and_sign_event(
 					PduBuilder::state(user_id.to_string(), &content),
 					sender_user,
-					room_id,
+					Some(room_id),
 					&state_lock,
 				)
 				.await?;
 
-			let invite_room_state = services.rooms.state.summary_stripped(&pdu).await;
+			let invite_room_state = services.rooms.state.summary_stripped(&pdu, room_id).await;
 
 			drop(state_lock);
 
@@ -227,7 +227,7 @@ pub(crate) async fn invite_helper(
 		.build_and_append_pdu(
 			PduBuilder::state(user_id.to_string(), &content),
 			sender_user,
-			room_id,
+			Some(room_id),
 			&state_lock,
 		)
 		.await?;

src/api/client/membership/join.rs

@@ -18,7 +18,7 @@ use conduwuit::{
 	},
 	warn,
 };
-use futures::{FutureExt, StreamExt};
+use futures::{FutureExt, StreamExt, TryFutureExt};
 use ruma::{
 	CanonicalJsonObject, CanonicalJsonValue, OwnedRoomId, OwnedServerName, OwnedUserId, RoomId,
 	RoomVersionId, UserId,
@@ -553,12 +553,20 @@ async fn join_room_by_id_helper_remote(
 		.iter()
 		.stream()
 		.then(|pdu| {
+			debug!(?pdu, "Validating send_join response room_state event");
 			services
 				.server_keys
 				.validate_and_add_event_id_no_fetch(pdu, &room_version_id)
+				.inspect_err(|e| {
+					debug_warn!(
+						"Could not validate send_join response room_state event: {e:?}"
+					);
+				})
+				.inspect(|_| debug!("Completed validating send_join response room_state event"))
 		})
 		.ready_filter_map(Result::ok)
 		.fold(HashMap::new(), |mut state, (event_id, value)| async move {
+			debug!(?event_id, "Processing send_join response room_state event");
 			let pdu = match PduEvent::from_id_val(&event_id, value.clone()) {
 				| Ok(pdu) => pdu,
 				| Err(e) => {
@@ -566,9 +574,10 @@ async fn join_room_by_id_helper_remote(
 					return state;
 				},
 			};
-
+			debug!(event_id = ?event_id.clone(), "Adding PDU outlier for send_join response room_state event");
 			services.rooms.outlier.add_pdu_outlier(&event_id, &value);
 			if let Some(state_key) = &pdu.state_key {
+				debug!(?state_key, "Creating shortstatekey for state event in send_join response");
 				let shortstatekey = services
 					.rooms
 					.short
@@ -577,7 +586,7 @@ async fn join_room_by_id_helper_remote(
 
 				state.insert(shortstatekey, pdu.event_id.clone());
 			}
-
+			debug!("Completed send_join response");
 			state
 		})
 		.await;
@@ -618,6 +627,9 @@ async fn join_room_by_id_helper_remote(
 		&parsed_join_pdu,
 		None, // TODO: third party invite
 		|k, s| state_fetch(k.clone(), s.into()),
+		&state_fetch(StateEventType::RoomCreate, "".into())
+			.await
+			.expect("create event is missing from send_join auth"),
 	)
 	.await
 	.map_err(|e| err!(Request(Forbidden(warn!("Auth check failed: {e:?}")))))?;
@@ -665,7 +677,7 @@ async fn join_room_by_id_helper_remote(
 	let statehash_after_join = services
 		.rooms
 		.state
-		.append_to_state(&parsed_join_pdu)
+		.append_to_state(&parsed_join_pdu, room_id)
 		.await?;
 
 	info!("Appending new room join event");
@@ -677,6 +689,7 @@ async fn join_room_by_id_helper_remote(
 			join_event,
 			once(parsed_join_pdu.event_id.borrow()),
 			&state_lock,
+			room_id,
 		)
 		.await?;
 
@@ -776,7 +789,7 @@ async fn join_room_by_id_helper_local(
 		.build_and_append_pdu(
 			PduBuilder::state(sender_user.to_string(), &content),
 			sender_user,
-			room_id,
+			Some(room_id),
 			&state_lock,
 		)
 		.await

src/api/client/membership/kick.rs

@@ -54,7 +54,7 @@ pub(crate) async fn kick_user_route(
 				..event
 			}),
 			sender_user,
-			&body.room_id,
+			Some(&body.room_id),
 			&state_lock,
 		)
 		.await?;

src/api/client/membership/knock.rs

@@ -373,7 +373,7 @@ async fn knock_room_helper_local(
 		.build_and_append_pdu(
 			PduBuilder::state(sender_user.to_string(), &content),
 			sender_user,
-			room_id,
+			Some(room_id),
 			&state_lock,
 		)
 		.await
@@ -502,6 +502,7 @@ async fn knock_room_helper_local(
 			knock_event,
 			once(parsed_knock_pdu.event_id.borrow()),
 			&state_lock,
+			room_id,
 		)
 		.await?;
 
@@ -672,7 +673,7 @@ async fn knock_room_helper_remote(
 	let statehash_after_knock = services
 		.rooms
 		.state
-		.append_to_state(&parsed_knock_pdu)
+		.append_to_state(&parsed_knock_pdu, room_id)
 		.await?;
 
 	info!("Updating membership locally to knock state with provided stripped state events");
@@ -701,6 +702,7 @@ async fn knock_room_helper_remote(
 			knock_event,
 			once(parsed_knock_pdu.event_id.borrow()),
 			&state_lock,
+			room_id,
 		)
 		.await?;
 

src/api/client/membership/leave.rs

@@ -206,7 +206,7 @@ pub async fn leave_room(
 					..event
 				}),
 				user_id,
-				room_id,
+				Some(room_id),
 				&state_lock,
 			)
 			.await?;

src/api/client/membership/mod.rs

@@ -70,9 +70,10 @@ pub(crate) async fn banned_room_check(
 
 	if let Some(room_id) = room_id {
 		if services.rooms.metadata.is_banned(room_id).await
-			|| services
+			|| (room_id.server_name().is_some()
+				&& services
 					.moderation
-				.is_remote_server_forbidden(room_id.server_name().expect("legacy room mxid"))
+					.is_remote_server_forbidden(room_id.server_name().expect("legacy room mxid")))
 		{
 			warn!(
 				"User {user_id} who is not an admin attempted to send an invite for or \

src/api/client/membership/unban.rs

@@ -47,7 +47,7 @@ pub(crate) async fn unban_user_route(
 				..current_member_content
 			}),
 			sender_user,
-			&body.room_id,
+			Some(&body.room_id),
 			&state_lock,
 		)
 		.await?;

src/api/client/message.rs

@@ -309,7 +309,7 @@ pub(crate) async fn visibility_filter(
 	services
 		.rooms
 		.state_accessor
-		.user_can_see_event(user_id, pdu.room_id(), pdu.event_id())
+		.user_can_see_event(user_id, &pdu.room_id_or_hash(), pdu.event_id())
 		.await
 		.then_some(item)
 }

src/api/client/profile.rs

@@ -423,7 +423,7 @@ pub async fn update_all_rooms(
 		if let Err(e) = services
 			.rooms
 			.timeline
-			.build_and_append_pdu(pdu_builder, user_id, room_id, &state_lock)
+			.build_and_append_pdu(pdu_builder, user_id, Some(room_id), &state_lock)
 			.await
 		{
 			warn!(%user_id, %room_id, "Failed to update/send new profile join membership update in room: {e}");

src/api/client/redact.rs

@@ -36,7 +36,7 @@ pub(crate) async fn redact_event_route(
 				})
 			},
 			sender_user,
-			&body.room_id,
+			Some(&body.room_id),
 			&state_lock,
 		)
 		.await?;

src/api/client/relations.rs

@@ -222,7 +222,7 @@ async fn visibility_filter<Pdu: Event + Send + Sync>(
 	services
 		.rooms
 		.state_accessor
-		.user_can_see_event(sender_user, pdu.room_id(), pdu.event_id())
+		.user_can_see_event(sender_user, &pdu.room_id_or_hash(), pdu.event_id())
 		.await
 		.then_some(item)
 }

src/api/client/report.rs

@@ -2,7 +2,7 @@ use std::{fmt::Write as _, ops::Mul, time::Duration};
 
 use axum::extract::State;
 use axum_client_ip::InsecureClientIp;
-use conduwuit::{Err, Result, debug_info, info, matrix::pdu::PduEvent, utils::ReadyExt};
+use conduwuit::{Err, Event, Result, debug_info, info, matrix::pdu::PduEvent, utils::ReadyExt};
 use conduwuit_service::Services;
 use rand::Rng;
 use ruma::{
@@ -200,7 +200,7 @@ async fn is_event_report_valid(
 		 valid"
 	);
 
-	if room_id != pdu.room_id {
+	if room_id != &pdu.room_id_or_hash() {
 		return Err!(Request(NotFound("Event ID does not belong to the reported room",)));
 	}
 

src/api/client/room/create.rs

@@ -2,7 +2,7 @@ use std::collections::BTreeMap;
 
 use axum::extract::State;
 use conduwuit::{
-	Err, Result, debug_info, debug_warn, err, info,
+	Err, Result, RoomVersion, debug, debug_info, debug_warn, err, info,
 	matrix::{StateKey, pdu::PduBuilder},
 	warn,
 };
@@ -68,51 +68,6 @@ pub(crate) async fn create_room_route(
 		return Err!(Request(UserSuspended("You cannot perform this action while suspended.")));
 	}
 
-	let room_id: OwnedRoomId = match &body.room_id {
-		| Some(custom_room_id) => custom_room_id_check(&services, custom_room_id)?,
-		| _ => RoomId::new(&services.server.name),
-	};
-
-	// check if room ID doesn't already exist instead of erroring on auth check
-	if services.rooms.short.get_shortroomid(&room_id).await.is_ok() {
-		return Err!(Request(RoomInUse("Room with that custom room ID already exists",)));
-	}
-
-	if body.visibility == room::Visibility::Public
-		&& services.server.config.lockdown_public_room_directory
-		&& !services.users.is_admin(sender_user).await
-		&& body.appservice_info.is_none()
-	{
-		warn!(
-			"Non-admin user {sender_user} tried to publish {room_id} to the room directory \
-			 while \"lockdown_public_room_directory\" is enabled"
-		);
-
-		if services.server.config.admin_room_notices {
-			services
-				.admin
-				.notice(&format!(
-					"Non-admin user {sender_user} tried to publish {room_id} to the room \
-					 directory while \"lockdown_public_room_directory\" is enabled"
-				))
-				.await;
-		}
-
-		return Err!(Request(Forbidden("Publishing rooms to the room directory is not allowed")));
-	}
-	let _short_id = services
-		.rooms
-		.short
-		.get_or_create_shortroomid(&room_id)
-		.await;
-	let state_lock = services.rooms.state.mutex.lock(&room_id).await;
-
-	let alias: Option<OwnedRoomAliasId> = match body.room_alias_name.as_ref() {
-		| Some(alias) =>
-			Some(room_alias_check(&services, alias, body.appservice_info.as_ref()).await?),
-		| _ => None,
-	};
-
 	let room_version = match body.room_version.clone() {
 		| Some(room_version) =>
 			if services.server.supported_room_version(&room_version) {
@@ -124,6 +79,51 @@ pub(crate) async fn create_room_route(
 			},
 		| None => services.server.config.default_room_version.clone(),
 	};
+	let room_features = RoomVersion::new(&room_version)?;
+
+	let room_id: Option<OwnedRoomId> = match room_features.room_ids_as_hashes {
+		| true => None,
+		| false => match &body.room_id {
+			| Some(custom_room_id) => Some(custom_room_id_check(&services, custom_room_id)?),
+			| None => Some(RoomId::new(services.globals.server_name())),
+		},
+	};
+
+	// check if room ID doesn't already exist instead of erroring on auth check
+	if let Some(ref room_id) = room_id {
+		if services.rooms.short.get_shortroomid(&room_id).await.is_ok() {
+			return Err!(Request(RoomInUse("Room with that custom room ID already exists",)));
+		}
+	}
+
+	if body.visibility == room::Visibility::Public
+		&& services.server.config.lockdown_public_room_directory
+		&& !services.users.is_admin(sender_user).await
+		&& body.appservice_info.is_none()
+	{
+		warn!(
+			"Non-admin user {sender_user} tried to publish {room_id:?} to the room directory \
+			 while \"lockdown_public_room_directory\" is enabled"
+		);
+
+		if services.server.config.admin_room_notices {
+			services
+				.admin
+				.notice(&format!(
+					"Non-admin user {sender_user} tried to publish {room_id:?} to the room \
+					 directory while \"lockdown_public_room_directory\" is enabled"
+				))
+				.await;
+		}
+
+		return Err!(Request(Forbidden("Publishing rooms to the room directory is not allowed")));
+	}
+
+	let alias: Option<OwnedRoomAliasId> = match body.room_alias_name.as_ref() {
+		| Some(alias) =>
+			Some(room_alias_check(&services, alias, body.appservice_info.as_ref()).await?),
+		| _ => None,
+	};
 
 	let create_content = match &body.creation_content {
 		| Some(content) => {
@@ -156,6 +156,10 @@ pub(crate) async fn create_room_route(
 					.try_into()
 					.map_err(|e| err!(Request(BadJson("Invalid creation content: {e}"))))?,
 			);
+			if room_version == V12 {
+				// TODO(hydra): v12 rooms cannot be federated until they are stable.
+				content.insert("m.federate".into(), false.into());
+			}
 			content
 		},
 		| None => {
@@ -164,18 +168,32 @@ pub(crate) async fn create_room_route(
 			let content = match room_version {
 				| V1 | V2 | V3 | V4 | V5 | V6 | V7 | V8 | V9 | V10 =>
 					RoomCreateEventContent::new_v1(sender_user.to_owned()),
-				| _ => RoomCreateEventContent::new_v11(),
+				| V11 => RoomCreateEventContent::new_v11(),
+				| _ => RoomCreateEventContent::new_v12(),
 			};
 			let mut content =
-				serde_json::from_str::<CanonicalJsonObject>(to_raw_value(&content)?.get())
-					.unwrap();
+				serde_json::from_str::<CanonicalJsonObject>(to_raw_value(&content)?.get())?;
 			content.insert("room_version".into(), json!(room_version.as_str()).try_into()?);
+			if room_version == V12 {
+				// TODO(hydra): v12 rooms cannot be federated until they are stable.
+				content.insert("m.federate".into(), false.into());
+			}
 			content
 		},
 	};
 
+	let state_lock = match room_id.clone() {
+		| Some(room_id) => services.rooms.state.mutex.lock(&room_id).await,
+		| None => {
+			let temp_room_id = RoomId::new(services.globals.server_name());
+			debug_info!("Locking temporary room state mutex for {temp_room_id}");
+			services.rooms.state.mutex.lock(&temp_room_id).await
+		},
+	};
+
 	// 1. The room create event
-	services
+	debug!("Creating room create event for {sender_user} in room {room_id:?}");
+	let create_event_id = services
 		.rooms
 		.timeline
 		.build_and_append_pdu(
@@ -186,13 +204,26 @@ pub(crate) async fn create_room_route(
 				..Default::default()
 			},
 			sender_user,
-			&room_id,
+			None,
 			&state_lock,
 		)
 		.boxed()
 		.await?;
+	debug!("Created room create event with ID {}", create_event_id);
+	let room_id = match room_id {
+		| Some(room_id) => room_id,
+		| None => {
+			let as_room_id = create_event_id.as_str().replace('$', "!");
+			debug_info!("Creating room with v12 room ID {as_room_id}");
+			RoomId::parse(&as_room_id)?.to_owned()
+		},
+	};
+	drop(state_lock);
+	debug!("Room created with ID {room_id}");
+	let state_lock = services.rooms.state.mutex.lock(&room_id).await;
 
 	// 2. Let the room creator join
+	debug_info!("Joining {sender_user} to room {room_id}");
 	services
 		.rooms
 		.timeline
@@ -205,7 +236,7 @@ pub(crate) async fn create_room_route(
 				..RoomMemberEventContent::new(MembershipState::Join)
 			}),
 			sender_user,
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.boxed()
@@ -235,10 +266,28 @@ pub(crate) async fn create_room_route(
 		}
 	}
 
+	let mut creators: Vec<OwnedUserId> = vec![sender_user.to_owned()];
+	if let Some(additional_creators) = create_content.get("additional_creators") {
+		if let Some(additional_creators) = additional_creators.as_array() {
+			for creator in additional_creators {
+				if let Some(creator) = creator.as_str() {
+					if let Ok(creator) = OwnedUserId::parse(creator) {
+						creators.push(creator.clone());
+						users.insert(creator.clone(), int!(100));
+					}
+				}
+			}
+		}
+	}
+	if !(RoomVersion::new(&room_version)?).explicitly_privilege_room_creators {
+		creators.clear();
+	}
+
 	let power_levels_content = default_power_levels_content(
 		body.power_level_content_override.as_ref(),
 		&body.visibility,
 		users,
+		creators,
 	)?;
 
 	services
@@ -252,7 +301,7 @@ pub(crate) async fn create_room_route(
 				..Default::default()
 			},
 			sender_user,
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.boxed()
@@ -269,7 +318,7 @@ pub(crate) async fn create_room_route(
 					alt_aliases: vec![],
 				}),
 				sender_user,
-				&room_id,
+				Some(&room_id),
 				&state_lock,
 			)
 			.boxed()
@@ -292,7 +341,7 @@ pub(crate) async fn create_room_route(
 				}),
 			),
 			sender_user,
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.boxed()
@@ -308,7 +357,7 @@ pub(crate) async fn create_room_route(
 				&RoomHistoryVisibilityEventContent::new(HistoryVisibility::Shared),
 			),
 			sender_user,
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.boxed()
@@ -327,7 +376,7 @@ pub(crate) async fn create_room_route(
 				}),
 			),
 			sender_user,
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.boxed()
@@ -363,7 +412,7 @@ pub(crate) async fn create_room_route(
 		services
 			.rooms
 			.timeline
-			.build_and_append_pdu(pdu_builder, sender_user, &room_id, &state_lock)
+			.build_and_append_pdu(pdu_builder, sender_user, Some(&room_id), &state_lock)
 			.boxed()
 			.await?;
 	}
@@ -376,7 +425,7 @@ pub(crate) async fn create_room_route(
 			.build_and_append_pdu(
 				PduBuilder::state(String::new(), &RoomNameEventContent::new(name.clone())),
 				sender_user,
-				&room_id,
+				Some(&room_id),
 				&state_lock,
 			)
 			.boxed()
@@ -390,7 +439,7 @@ pub(crate) async fn create_room_route(
 			.build_and_append_pdu(
 				PduBuilder::state(String::new(), &RoomTopicEventContent { topic: topic.clone() }),
 				sender_user,
-				&room_id,
+				Some(&room_id),
 				&state_lock,
 			)
 			.boxed()
@@ -450,6 +499,7 @@ fn default_power_levels_content(
 	power_level_content_override: Option<&Raw<RoomPowerLevelsEventContent>>,
 	visibility: &room::Visibility,
 	users: BTreeMap<OwnedUserId, Int>,
+	creators: Vec<OwnedUserId>,
 ) -> Result<serde_json::Value> {
 	let mut power_levels_content =
 		serde_json::to_value(RoomPowerLevelsEventContent { users, ..Default::default() })
@@ -499,6 +549,19 @@ fn default_power_levels_content(
 		}
 	}
 
+	if !creators.is_empty() {
+		// Raise the default power level of tombstone to 150
+		power_levels_content["events"]["m.room.tombstone"] =
+			serde_json::to_value(150).expect("150 is valid Value");
+		for creator in creators {
+			// Omit creators from the power level list altogether
+			power_levels_content["users"]
+				.as_object_mut()
+				.expect("users is an object")
+				.remove(creator.as_str());
+		}
+	}
+
 	Ok(power_levels_content)
 }
 

src/api/client/room/upgrade.rs

@@ -91,7 +91,7 @@ pub(crate) async fn upgrade_room_route(
 				replacement_room: replacement_room.clone(),
 			}),
 			sender_user,
-			&body.room_id,
+			Some(&body.room_id),
 			&state_lock,
 		)
 		.await?;
@@ -173,7 +173,7 @@ pub(crate) async fn upgrade_room_route(
 				timestamp: None,
 			},
 			sender_user,
-			&replacement_room,
+			Some(&replacement_room),
 			&state_lock,
 		)
 		.boxed()
@@ -204,7 +204,7 @@ pub(crate) async fn upgrade_room_route(
 				timestamp: None,
 			},
 			sender_user,
-			&replacement_room,
+			Some(&replacement_room),
 			&state_lock,
 		)
 		.boxed()
@@ -243,7 +243,7 @@ pub(crate) async fn upgrade_room_route(
 						..Default::default()
 					},
 					sender_user,
-					&replacement_room,
+					Some(&replacement_room),
 					&state_lock,
 				)
 				.boxed()
@@ -302,7 +302,7 @@ pub(crate) async fn upgrade_room_route(
 				..power_levels_event_content
 			}),
 			sender_user,
-			&body.room_id,
+			Some(&body.room_id),
 			&state_lock,
 		)
 		.boxed()
@@ -352,7 +352,7 @@ pub(crate) async fn upgrade_room_route(
 					..Default::default()
 				},
 				sender_user,
-				space_id,
+				Some(space_id),
 				&state_lock,
 			)
 			.boxed()
@@ -376,7 +376,7 @@ pub(crate) async fn upgrade_room_route(
 					..Default::default()
 				},
 				sender_user,
-				space_id,
+				Some(space_id),
 				&state_lock,
 			)
 			.boxed()

src/api/client/send.rs

@@ -80,7 +80,7 @@ pub(crate) async fn send_message_event_route(
 				..Default::default()
 			},
 			sender_user,
-			&body.room_id,
+			Some(&body.room_id),
 			&state_lock,
 		)
 		.await?;

src/api/client/state.rs

@@ -201,7 +201,7 @@ async fn send_state_event_for_key_helper(
 				..Default::default()
 			},
 			sender,
-			room_id,
+			Some(room_id),
 			&state_lock,
 		)
 		.await?;

src/api/client/sync/v3.rs

@@ -457,7 +457,7 @@ async fn handle_left_room(
 			state_key: Some(sender_user.as_str().into()),
 			unsigned: None,
 			// The following keys are dropped on conversion
-			room_id: room_id.clone(),
+			room_id: Some(room_id.clone()),
 			prev_events: vec![],
 			depth: uint!(1),
 			auth_events: vec![],

src/api/server/backfill.rs

@@ -2,7 +2,7 @@ use std::cmp;
 
 use axum::extract::State;
 use conduwuit::{
-	PduCount, Result,
+	Event, PduCount, Result,
 	utils::{IterStream, ReadyExt, stream::TryTools},
 };
 use futures::{FutureExt, StreamExt, TryStreamExt};
@@ -68,7 +68,7 @@ pub(crate) async fn get_backfill_route(
 				Ok(services
 					.rooms
 					.state_accessor
-					.server_can_see_event(body.origin(), &pdu.room_id, &pdu.event_id)
+					.server_can_see_event(body.origin(), &pdu.room_id_or_hash(), &pdu.event_id)
 					.await
 					.then_some(pdu))
 			})

src/api/server/make_join.rs

@@ -122,7 +122,7 @@ pub(crate) async fn create_join_event_template_route(
 				..RoomMemberEventContent::new(MembershipState::Join)
 			}),
 			&body.user_id,
-			&body.room_id,
+			Some(&body.room_id),
 			&state_lock,
 		)
 		.await?;

src/api/server/make_knock.rs

@@ -95,7 +95,7 @@ pub(crate) async fn create_knock_event_template_route(
 				&RoomMemberEventContent::new(MembershipState::Knock),
 			),
 			&body.user_id,
-			&body.room_id,
+			Some(&body.room_id),
 			&state_lock,
 		)
 		.await?;

src/api/server/make_leave.rs

@@ -45,7 +45,7 @@ pub(crate) async fn create_leave_event_template_route(
 				&RoomMemberEventContent::new(MembershipState::Leave),
 			),
 			&body.user_id,
-			&body.room_id,
+			Some(&body.room_id),
 			&state_lock,
 		)
 		.await?;

src/api/server/send.rs

@@ -138,6 +138,7 @@ async fn handle(
 	pdus: impl Stream<Item = Pdu> + Send,
 	edus: impl Stream<Item = Edu> + Send,
 ) -> Result<ResolvedMap> {
+	// TODO(hydra): Does having no room ID break this?
 	// group pdus by room
 	let pdus = pdus
 		.collect()
@@ -186,6 +187,7 @@ async fn handle_room(
 		.lock(&room_id)
 		.await;
 
+	// TODO(hydra): We might be missing a room ID
 	let room_id = &room_id;
 	pdus.try_stream()
 		.and_then(|(_, event_id, value)| async move {

src/api/server/send_knock.rs

@@ -175,7 +175,11 @@ pub(crate) async fn create_knock_event_v1_route(
 		.send_pdu_room(&body.room_id, &pdu_id)
 		.await?;
 
-	let knock_room_state = services.rooms.state.summary_stripped(&pdu).await;
+	let knock_room_state = services
+		.rooms
+		.state
+		.summary_stripped(&pdu, &body.room_id)
+		.await;
 
 	Ok(send_knock::v1::Response { knock_room_state })
 }

src/core/info/room_version.rs

@@ -17,8 +17,12 @@ pub const STABLE_ROOM_VERSIONS: &[RoomVersionId] = &[
 ];
 
 /// Experimental, partially supported room versions
-pub const UNSTABLE_ROOM_VERSIONS: &[RoomVersionId] =
-	&[RoomVersionId::V3, RoomVersionId::V4, RoomVersionId::V5];
+pub const UNSTABLE_ROOM_VERSIONS: &[RoomVersionId] = &[
+	RoomVersionId::V3,
+	RoomVersionId::V4,
+	RoomVersionId::V5,
+	RoomVersionId::V12,
+];
 
 type RoomVersion = (RoomVersionId, RoomVersionStability);
 

src/core/matrix/event.rs

@@ -10,7 +10,7 @@ mod unsigned;
 use std::fmt::Debug;
 
 use ruma::{
-	CanonicalJsonObject, EventId, MilliSecondsSinceUnixEpoch, OwnedEventId, RoomId,
+	CanonicalJsonObject, EventId, MilliSecondsSinceUnixEpoch, OwnedEventId, OwnedRoomId, RoomId,
 	RoomVersionId, UserId, events::TimelineEventType,
 };
 use serde::Deserialize;
@@ -168,7 +168,12 @@ pub trait Event: Clone + Debug {
 	fn redacts(&self) -> Option<&EventId>;
 
 	/// The `RoomId` of this event.
-	fn room_id(&self) -> &RoomId;
+	fn room_id(&self) -> Option<&RoomId>;
+
+	/// The `RoomId` or hash of this event.
+	/// This should only be preferred over room_id() if the event is a v12
+	/// create event.
+	fn room_id_or_hash(&self) -> OwnedRoomId;
 
 	/// The `UserId` of this event.
 	fn sender(&self) -> &UserId;

src/core/matrix/event/filter.rs

@@ -32,12 +32,16 @@ impl<E: Event> Matches<E> for &RoomEventFilter {
 }
 
 fn matches_room<E: Event>(event: &E, filter: &RoomEventFilter) -> bool {
-	if filter.not_rooms.iter().any(is_equal_to!(event.room_id())) {
+	if filter
+		.not_rooms
+		.iter()
+		.any(is_equal_to!(event.room_id().unwrap()))
+	{
 		return false;
 	}
 
 	if let Some(rooms) = filter.rooms.as_ref() {
-		if !rooms.iter().any(is_equal_to!(event.room_id())) {
+		if !rooms.iter().any(is_equal_to!(event.room_id().unwrap())) {
 			return false;
 		}
 	}

src/core/matrix/pdu.rs

@@ -31,7 +31,7 @@ use crate::Result;
 pub struct Pdu {
 	pub event_id: OwnedEventId,
 
-	pub room_id: OwnedRoomId,
+	pub room_id: Option<OwnedRoomId>,
 
 	pub sender: OwnedUserId,
 
@@ -110,7 +110,19 @@ impl Event for Pdu {
 	fn redacts(&self) -> Option<&EventId> { self.redacts.as_deref() }
 
 	#[inline]
-	fn room_id(&self) -> &RoomId { &self.room_id }
+	fn room_id(&self) -> Option<&RoomId> { self.room_id.as_deref() }
+
+	#[inline]
+	fn room_id_or_hash(&self) -> OwnedRoomId {
+		if let Some(room_id) = &self.room_id {
+			room_id.clone()
+		} else {
+			let constructed_hash = "!".to_owned() + &self.event_id.as_str()[1..];
+			RoomId::parse(&constructed_hash)
+				.expect("event ID can be indexed")
+				.to_owned()
+		}
+	}
 
 	#[inline]
 	fn sender(&self) -> &UserId { &self.sender }
@@ -163,7 +175,19 @@ impl Event for &Pdu {
 	fn redacts(&self) -> Option<&EventId> { self.redacts.as_deref() }
 
 	#[inline]
-	fn room_id(&self) -> &RoomId { &self.room_id }
+	fn room_id(&self) -> Option<&RoomId> { self.room_id.as_ref().map(AsRef::as_ref) }
+
+	#[inline]
+	fn room_id_or_hash(&self) -> OwnedRoomId {
+		if let Some(room_id) = &self.room_id {
+			room_id.clone()
+		} else {
+			let constructed_hash = "!".to_owned() + &self.event_id.as_str()[1..];
+			RoomId::parse(&constructed_hash)
+				.expect("event ID can be indexed")
+				.to_owned()
+		}
+	}
 
 	#[inline]
 	fn sender(&self) -> &UserId { &self.sender }

src/core/matrix/state_res/benches.rs

@@ -406,7 +406,7 @@ where
 
 	Pdu {
 		event_id: id.try_into().unwrap(),
-		room_id: room_id().to_owned(),
+		room_id: Some(room_id().to_owned()),
 		sender: sender.to_owned(),
 		origin_server_ts: ts.try_into().unwrap(),
 		state_key: state_key.map(Into::into),

src/core/matrix/state_res/event_auth.rs

@@ -2,10 +2,10 @@ use std::{borrow::Borrow, collections::BTreeSet};
 
 use futures::{
 	Future,
-	future::{OptionFuture, join3},
+	future::{OptionFuture, join, join3},
 };
 use ruma::{
-	Int, OwnedUserId, RoomVersionId, UserId,
+	Int, OwnedRoomId, OwnedUserId, RoomVersionId, UserId,
 	events::room::{
 		create::RoomCreateEventContent,
 		join_rules::{JoinRule, RoomJoinRulesEventContent},
@@ -44,6 +44,15 @@ struct RoomMemberContentFields {
 	join_authorised_via_users_server: Option<Raw<OwnedUserId>>,
 }
 
+#[derive(Deserialize)]
+struct RoomCreateContentFields {
+	room_version: Option<Raw<RoomVersionId>>,
+	creator: Option<Raw<IgnoredAny>>,
+	additional_creators: Option<Vec<Raw<OwnedUserId>>>,
+	#[serde(rename = "m.federate", default = "ruma::serde::default_true")]
+	federate: bool,
+}
+
 /// For the given event `kind` what are the relevant auth events that are needed
 /// to authenticate this `content`.
 ///
@@ -56,16 +65,24 @@ pub fn auth_types_for_event(
 	sender: &UserId,
 	state_key: Option<&str>,
 	content: &RawJsonValue,
+	room_version: &RoomVersion,
 ) -> serde_json::Result<Vec<(StateEventType, StateKey)>> {
 	if kind == &TimelineEventType::RoomCreate {
 		return Ok(vec![]);
 	}
 
-	let mut auth_types = vec![
+	let mut auth_types = if room_version.room_ids_as_hashes {
+		vec![
+			(StateEventType::RoomPowerLevels, StateKey::new()),
+			(StateEventType::RoomMember, sender.as_str().into()),
+		]
+	} else {
+		vec![
 			(StateEventType::RoomPowerLevels, StateKey::new()),
 			(StateEventType::RoomMember, sender.as_str().into()),
 			(StateEventType::RoomCreate, StateKey::new()),
-	];
+		]
+	};
 
 	if kind == &TimelineEventType::RoomMember {
 		#[derive(Deserialize)]
@@ -141,6 +158,7 @@ pub async fn auth_check<E, F, Fut>(
 	incoming_event: &E,
 	current_third_party_invite: Option<&E>,
 	fetch_state: F,
+	create_event: &E,
 ) -> Result<bool, Error>
 where
 	F: Fn(&StateEventType, &str) -> Fut + Send,
@@ -169,12 +187,6 @@ where
 	//
 	// 1. If type is m.room.create:
 	if *incoming_event.event_type() == TimelineEventType::RoomCreate {
-		#[derive(Deserialize)]
-		struct RoomCreateContentFields {
-			room_version: Option<Raw<RoomVersionId>>,
-			creator: Option<Raw<IgnoredAny>>,
-		}
-
 		debug!("start m.room.create check");
 
 		// If it has any previous events, reject
@@ -184,15 +196,17 @@ where
 		}
 
 		// If the domain of the room_id does not match the domain of the sender, reject
-		let Some(room_id_server_name) = incoming_event.room_id().server_name() else {
+		if incoming_event.room_id().is_some() {
+			let Some(room_id_server_name) = incoming_event.room_id().unwrap().server_name()
+			else {
 				warn!("room ID has no servername");
 				return Ok(false);
 			};
-
 			if room_id_server_name != sender.server_name() {
 				warn!("servername of room ID does not match servername of sender");
 				return Ok(false);
 			}
+		}
 
 		// If content.room_version is present and is not a recognized version, reject
 		let content: RoomCreateContentFields = from_json_str(incoming_event.content().get())?;
@@ -204,7 +218,15 @@ where
 			return Ok(false);
 		}
 
-		if !room_version.use_room_create_sender {
+		// TODO(hydra): If the create event has a room_id, reject
+		if room_version.room_ids_as_hashes && incoming_event.room_id().is_some() {
+			warn!("this room version does not support room IDs in m.room.create");
+			return Ok(false);
+		}
+
+		if !room_version.use_room_create_sender
+			&& !room_version.explicitly_privilege_room_creators
+		{
 			// If content has no creator field, reject
 			if content.creator.is_none() {
 				warn!("no creator field found in m.room.create content");
@@ -216,6 +238,8 @@ where
 		return Ok(true);
 	}
 
+	// NOTE(hydra): We must have an event ID from this point forward.
+
 	/*
 	// TODO: In the past this code was commented as it caused problems with Synapse. This is no
 	// longer the case. This needs to be implemented.
@@ -242,54 +266,102 @@ where
 	}
 	*/
 
-	let (room_create_event, power_levels_event, sender_member_event) = join3(
-		fetch_state(&StateEventType::RoomCreate, ""),
+	let (power_levels_event, sender_member_event) = join(
+		// fetch_state(&StateEventType::RoomCreate, ""),
 		fetch_state(&StateEventType::RoomPowerLevels, ""),
 		fetch_state(&StateEventType::RoomMember, sender.as_str()),
 	)
 	.await;
 
-	let room_create_event = match room_create_event {
-		| None => {
-			warn!("no m.room.create event in auth chain");
+	// TODO(hydra): Re-enable <v12 checks
+	// let room_create_event = match room_create_event {
+	// 	| None => {
+	// 		// Room was either v11 with no create event, or v12+ room
+	// 		if incoming_event.room_id().is_some() {
+	// 			// invalid v11
+	// 			warn!("no m.room.create event found in claimed state");
+	// 			return Ok(false);
+	// 		}
+	// 		// v12 room
+	// 		debug!("no m.room.create event found, assuming v12 room");
+	// 		create_event.clone()
+	// 	},
+	// 	| Some(e) => e,
+	// };
+	let room_create_event = create_event.clone();
+
+	// Get the content of the room create event, used later.
+	let room_create_content: RoomCreateContentFields =
+		from_json_str(room_create_event.content().get())?;
+	if room_create_content
+		.room_version
+		.is_some_and(|v| v.deserialize().is_err())
+	{
+		warn!("invalid room version found in m.room.create event");
 		return Ok(false);
-		},
-		| Some(e) => e,
+	}
+	let expected_room_id = match room_version.room_ids_as_hashes {
+		// If the room version uses hashes, we replace the create event's event ID leading sigil
+		// with !
+		| true => OwnedRoomId::try_from(room_create_event.event_id().as_str().replace('$', "!"))
+			.expect("Failed to convert event ID to room ID")
+			.clone(),
+		| false => room_create_event.room_id().unwrap().to_owned(),
 	};
 
-	if incoming_event.room_id() != room_create_event.room_id() {
-		warn!("room_id of incoming event does not match room_id of m.room.create event");
+	if incoming_event.room_id().unwrap() != expected_room_id {
+		warn!(
+			expected = %expected_room_id,
+			received = %incoming_event.room_id().unwrap(),
+			"room_id of incoming event ({}) does not match room_id of m.room.create event ({})",
+			incoming_event.room_id().unwrap(),
+			expected_room_id,
+		);
+		return Ok(false);
+	}
+
+	// If the create event is referenced in the event's auth events, and this is a
+	// v12 room, reject
+	let claims_create_event = incoming_event
+		.auth_events()
+		.any(|id| id == room_create_event.event_id());
+	if room_version.room_ids_as_hashes && claims_create_event {
+		warn!("m.room.create event incorrectly found in auth events");
+		return Ok(false);
+	} else if !room_version.room_ids_as_hashes && !claims_create_event {
+		// If the create event is not referenced in the event's auth events, and this is
+		// a v11 room, reject
+		warn!("no m.room.create event found in auth events");
 		return Ok(false);
 	}
 
 	if let Some(ref pe) = power_levels_event {
-		if pe.room_id() != room_create_event.room_id() {
-			warn!("room_id of power levels event does not match room_id of m.room.create event");
+		if *pe.room_id().unwrap() != expected_room_id {
+			warn!(
+				expected = %expected_room_id,
+				received = %pe.room_id().unwrap(),
+				"room_id of power levels event does not match room_id of m.room.create event"
+			);
 			return Ok(false);
 		}
 	}
 
 	// 3. If event does not have m.room.create in auth_events reject
-	if !incoming_event
-		.auth_events()
-		.any(|id| id == room_create_event.event_id())
-	{
-		warn!("no m.room.create event in auth events");
-		return Ok(false);
-	}
+	// removed as part of Hydra.
+	// TODO: reintroduce this for <v12 lol
+	// if !incoming_event
+	// 	.auth_events()
+	// 	.any(|id| id == room_create_event.event_id())
+	// {
+	// 	warn!("no m.room.create event in auth events");
+	// 	return Ok(false);
+	// }
 
 	// If the create event content has the field m.federate set to false and the
 	// sender domain of the event does not match the sender domain of the create
 	// event, reject.
-	#[derive(Deserialize)]
-	#[allow(clippy::items_after_statements)]
-	struct RoomCreateContentFederate {
-		#[serde(rename = "m.federate", default = "ruma::serde::default_true")]
-		federate: bool,
-	}
-	let room_create_content: RoomCreateContentFederate =
-		from_json_str(room_create_event.content().get())?;
-	if !room_create_content.federate
+	if !room_version.room_ids_as_hashes
+		&& !room_create_content.federate
 		&& room_create_event.sender().server_name() != incoming_event.sender().server_name()
 	{
 		warn!(
@@ -377,6 +449,7 @@ where
 			&user_for_join_auth_membership,
 			&room_create_event,
 		)? {
+			warn!("membership change not valid for some reason");
 			return Ok(false);
 		}
 
@@ -394,8 +467,16 @@ where
 		},
 	};
 
-	if sender_member_event.room_id() != room_create_event.room_id() {
-		warn!("room_id of incoming event does not match room_id of m.room.create event");
+	if sender_member_event
+		.room_id()
+		.expect("we have a room ID for non create events")
+		!= room_create_event.room_id_or_hash()
+	{
+		warn!(
+			"room_id of incoming event ({}) does not match room_id of m.room.create event ({})",
+			sender_member_event.room_id_or_hash(),
+			room_create_event.room_id_or_hash()
+		);
 		return Ok(false);
 	}
 
@@ -417,7 +498,7 @@ where
 	}
 
 	// If type is m.room.third_party_invite
-	let sender_power_level = match &power_levels_event {
+	let mut sender_power_level = match &power_levels_event {
 		| Some(pl) => {
 			let content =
 				deserialize_power_levels_content_fields(pl.content().get(), room_version)?;
@@ -439,6 +520,24 @@ where
 			if is_creator { int!(100) } else { int!(0) }
 		},
 	};
+	if room_version.explicitly_privilege_room_creators {
+		// If the user sent the create event, or is listed in additional_creators, just
+		// give them Int::MAX
+		if sender == room_create_event.sender()
+			|| room_create_content
+				.additional_creators
+				.as_ref()
+				.is_some_and(|creators| {
+					creators
+						.iter()
+						.any(|c| c.deserialize().is_ok_and(|c| c == *sender))
+				}) {
+			trace!("privileging room creator or additional creator");
+			// This user is the room creator or an additional creator, give them max power
+			// level
+			sender_power_level = Int::MAX;
+		}
+	}
 
 	// Allow if and only if sender's current power level is greater than
 	// or equal to the invite level
@@ -554,6 +653,7 @@ where
 	struct GetThirdPartyInvite {
 		third_party_invite: Option<Raw<ThirdPartyInvite>>,
 	}
+	let create_content = from_json_str::<RoomCreateContentFields>(create_room.content().get())?;
 	let content = current_event.content();
 
 	let target_membership = from_json_str::<GetMembership>(content.get())?.membership;
@@ -576,15 +676,36 @@ where
 		| None => RoomPowerLevelsEventContent::default(),
 	};
 
-	let sender_power = power_levels
+	let mut sender_power = power_levels
 		.users
 		.get(sender)
 		.or_else(|| sender_is_joined.then_some(&power_levels.users_default));
 
-	let target_power = power_levels.users.get(target_user).or_else(|| {
+	let mut target_power = power_levels.users.get(target_user).or_else(|| {
 		(target_membership == MembershipState::Join).then_some(&power_levels.users_default)
 	});
 
+	let mut creators = BTreeSet::new();
+	creators.insert(create_room.sender().to_owned());
+	if room_version.explicitly_privilege_room_creators {
+		// Explicitly privilege room creators
+		// If the sender sent the create event, or in additional_creators, give them
+		// Int::MAX. Same case for target.
+		if let Some(additional_creators) = &create_content.additional_creators {
+			for c in additional_creators {
+				if let Ok(c) = c.deserialize() {
+					creators.insert(c);
+				}
+			}
+		}
+		if creators.contains(sender) {
+			sender_power = Some(&Int::MAX);
+		}
+		if creators.contains(target_user) {
+			target_power = Some(&Int::MAX);
+		}
+	}
+
 	let mut join_rules = JoinRule::Invite;
 	if let Some(jr) = &join_rules_event {
 		join_rules = from_json_str::<RoomJoinRulesEventContent>(jr.content().get())?.join_rule;
@@ -597,7 +718,7 @@ where
 
 	let user_for_join_auth_is_valid = if let Some(user_for_join_auth) = user_for_join_auth {
 		// Is the authorised user allowed to invite users into this room
-		let (auth_user_pl, invite_level) = if let Some(pl) = &power_levels_event {
+		let (mut auth_user_pl, invite_level) = if let Some(pl) = &power_levels_event {
 			// TODO Refactor all powerlevel parsing
 			let invite =
 				deserialize_power_levels_content_invite(pl.content().get(), room_version)?.invite;
@@ -613,6 +734,9 @@ where
 		} else {
 			(int!(0), int!(0))
 		};
+		if creators.contains(user_for_join_auth) {
+			auth_user_pl = Int::MAX;
+		}
 		(user_for_join_auth_membership == &MembershipState::Join)
 			&& (auth_user_pl >= invite_level)
 	} else {
@@ -622,6 +746,7 @@ where
 
 	Ok(match target_membership {
 		| MembershipState::Join => {
+			debug!("starting target_membership=join check");
 			// 1. If the only previous event is an m.room.create and the state_key is the
 			//    creator,
 			// allow
@@ -633,7 +758,10 @@ where
 			let no_more_prev_events = prev_events.next().is_none();
 
 			if prev_event_is_create_event && no_more_prev_events {
-				let is_creator = if room_version.use_room_create_sender {
+				debug!("checking if sender is a room creator for initial membership event");
+				let is_creator = if room_version.explicitly_privilege_room_creators {
+					creators.contains(target_user) && creators.contains(sender)
+				} else if room_version.use_room_create_sender {
 					let creator = create_room.sender();
 
 					creator == sender && creator == target_user
@@ -647,10 +775,15 @@ where
 				};
 
 				if is_creator {
+					debug!("sender is room creator, allowing join");
 					return Ok(true);
 				}
+				debug!("sender is not room creator, proceeding with normal auth checks");
 			}
-
+			let membership_allows_join = matches!(
+				target_user_current_membership,
+				MembershipState::Join | MembershipState::Invite
+			);
 			if sender != target_user {
 				// If the sender does not match state_key, reject.
 				warn!("Can't make other user join");
@@ -659,39 +792,48 @@ where
 				// If the sender is banned, reject.
 				warn!(?target_user_membership_event_id, "Banned user can't join");
 				false
-			} else if (join_rules == JoinRule::Invite
-                    || room_version.allow_knocking && (join_rules == JoinRule::Knock || matches!(join_rules, JoinRule::KnockRestricted(_))))
-                // If the join_rule is invite then allow if membership state is invite or join
-                    && (target_user_current_membership == MembershipState::Join
-                        || target_user_current_membership == MembershipState::Invite)
-			{
-				true
-			} else if room_version.restricted_join_rules
-				&& matches!(join_rules, JoinRule::Restricted(_))
-				|| room_version.knock_restricted_join_rule
-					&& matches!(join_rules, JoinRule::KnockRestricted(_))
-			{
-				// If the join_rule is restricted or knock_restricted
-				if matches!(
-					target_user_current_membership,
-					MembershipState::Invite | MembershipState::Join
-				) {
-					// If membership state is join or invite, allow.
-					true
 			} else {
-					// If the join_authorised_via_users_server key in content is not a user with
-					// sufficient permission to invite other users, reject.
-					// Otherwise, allow.
-					user_for_join_auth_is_valid
+				match join_rules {
+					| JoinRule::Invite if !membership_allows_join => {
+						warn!("Join rule is invite but membership does not allow join");
+						false
+					},
+					| JoinRule::Knock if !room_version.allow_knocking => {
+						warn!("Join rule is knock but room version does not allow knocking");
+						false
+					},
+					| JoinRule::Knock if !membership_allows_join => {
+						warn!("Join rule is knock but membership does not allow join");
+						false
+					},
+					| JoinRule::KnockRestricted(_) if !room_version.knock_restricted_join_rule =>
+					{
+						warn!(
+							"Join rule is knock_restricted but room version does not support it"
+						);
+						false
+					},
+					| JoinRule::KnockRestricted(_) if !membership_allows_join => {
+						warn!("Join rule is knock_restricted but membership does not allow join");
+						false
+					},
+					| JoinRule::Restricted(_) | JoinRule::KnockRestricted(_) =>
+						if !user_for_join_auth_is_valid {
+							warn!(
+								"Join rule is a restricted one but no valid authorising user \
+								 was given"
+							);
+							false
+						} else {
+							true
+						},
+					| _ => true,
 				}
-			} else {
-				// If the join_rule is public, allow.
-				// Otherwise, reject.
-				join_rules == JoinRule::Public
 			}
 		},
 		| MembershipState::Invite => {
 			// If content has third_party_invite key
+			debug!("starting target_membership=invite check");
 			match third_party_invite.and_then(|i| i.deserialize().ok()) {
 				| Some(tp_id) =>
 					if target_user_current_membership == MembershipState::Ban {
@@ -849,6 +991,7 @@ fn can_send_event(event: &impl Event, ple: Option<&impl Event>, user_level: Int)
 		required_level = i64::from(event_type_power_level),
 		user_level = i64::from(user_level),
 		state_key = ?event.state_key(),
+		power_level_event_id = ?ple.map(|e| e.event_id().as_str()),
 		"permissions factors",
 	);
 

src/core/matrix/state_res/mod.rs

@@ -92,6 +92,11 @@ where
 	Pdu: Event + Clone + Send + Sync,
 	for<'b> &'b Pdu: Event + Send,
 {
+	use RoomVersionId::*;
+	let stateres_version = match room_version {
+		| V2 | V3 | V4 | V5 | V6 | V7 | V8 | V9 | V10 | V11 => 2.0,
+		| _ => 2.1,
+	};
 	debug!("State resolution starting");
 
 	// Split non-conflicting and conflicting state
@@ -108,13 +113,27 @@ where
 	debug!(count = conflicting.len(), "conflicting events");
 	trace!(map = ?conflicting, "conflicting events");
 
+	let conflicted_state_subgraph: HashSet<_> = if stateres_version >= 2.1 {
+		calculate_conflicted_subgraph(&conflicting, event_fetch)
+			.await
+			.ok_or_else(|| {
+				Error::InvalidPdu("Failed to calculate conflicted subgraph".to_owned())
+			})?
+	} else {
+		HashSet::new()
+	};
+	debug!(count = conflicted_state_subgraph.len(), "conflicted subgraph");
+	trace!(set = ?conflicted_state_subgraph, "conflicted subgraph");
+
 	let conflicting_values = conflicting.into_values().flatten().stream();
 
 	// `all_conflicted` contains unique items
 	// synapse says `full_set = {eid for eid in full_conflicted_set if eid in
 	// event_map}`
+	// Hydra: Also consider the conflicted state subgraph
 	let all_conflicted: HashSet<_> = get_auth_chain_diff(auth_chain_sets)
 		.chain(conflicting_values)
+		.chain(conflicted_state_subgraph.into_iter().stream())
 		.broad_filter_map(async |id| event_exists(id.clone()).await.then_some(id))
 		.collect()
 		.await;
@@ -150,6 +169,7 @@ where
 	// Sequentially auth check each control event.
 	let resolved_control = iterative_auth_check(
 		&room_version,
+		stateres_version,
 		sorted_control_levels.iter().stream().map(AsRef::as_ref),
 		clean.clone(),
 		&event_fetch,
@@ -183,10 +203,11 @@ where
 	let sorted_left_events =
 		mainline_sort(&events_to_resolve, power_event.cloned(), &event_fetch).await?;
 
-	trace!(list = ?sorted_left_events, "events left, sorted");
+	trace!(list = ?sorted_left_events, "events left, sorted, running iterative auth check");
 
 	let mut resolved_state = iterative_auth_check(
 		&room_version,
+		stateres_version,
 		sorted_left_events.iter().stream().map(AsRef::as_ref),
 		resolved_control, // The control events are added to the final resolved state
 		&event_fetch,
@@ -198,6 +219,7 @@ where
 	resolved_state.extend(clean);
 
 	debug!("state resolution finished");
+	trace!( map = ?resolved_state, "final resolved state" );
 
 	Ok(resolved_state)
 }
@@ -250,6 +272,52 @@ where
 	(unconflicted_state, conflicted_state)
 }
 
+/// Calculate the conflicted subgraph
+async fn calculate_conflicted_subgraph<F, Fut, E>(
+	conflicted: &StateMap<Vec<OwnedEventId>>,
+	fetch_event: &F,
+) -> Option<HashSet<OwnedEventId>>
+where
+	F: Fn(OwnedEventId) -> Fut + Sync,
+	Fut: Future<Output = Option<E>> + Send,
+	E: Event + Send + Sync,
+{
+	let conflicted_events: HashSet<_> = conflicted.values().flatten().cloned().collect();
+	let mut subgraph: HashSet<OwnedEventId> = HashSet::new();
+	let mut stack: Vec<Vec<OwnedEventId>> =
+		vec![conflicted_events.iter().cloned().collect::<Vec<_>>()];
+	let mut path: Vec<OwnedEventId> = Vec::new();
+	let mut seen: HashSet<OwnedEventId> = HashSet::new();
+	let next_event = |stack: &mut Vec<Vec<_>>, path: &mut Vec<_>| {
+		while stack.last().is_some_and(|s| s.is_empty()) {
+			stack.pop();
+			path.pop();
+		}
+		stack.last_mut().and_then(|s| s.pop())
+	};
+	while let Some(event_id) = next_event(&mut stack, &mut path) {
+		path.push(event_id.clone());
+		if subgraph.contains(&event_id) {
+			if path.len() > 1 {
+				subgraph.extend(path.iter().cloned());
+			}
+			path.pop();
+			continue;
+		}
+		if conflicted_events.contains(&event_id) && path.len() > 1 {
+			subgraph.extend(path.iter().cloned());
+		}
+		if seen.contains(&event_id) {
+			path.pop();
+			continue;
+		}
+		let evt = fetch_event(event_id.clone()).await?;
+		stack.push(evt.auth_events().map(ToOwned::to_owned).collect());
+		seen.insert(event_id);
+	}
+	Some(subgraph)
+}
+
 /// Returns a Vec of deduped EventIds that appear in some chains but not others.
 #[allow(clippy::arithmetic_side_effects)]
 fn get_auth_chain_diff<Id, Hasher>(
@@ -513,8 +581,10 @@ where
 /// For each `events_to_check` event we gather the events needed to auth it from
 /// the the `fetch_event` closure and verify each event using the
 /// `event_auth::auth_check` function.
+#[tracing::instrument(level = "trace", skip_all)]
 async fn iterative_auth_check<'a, E, F, Fut, S>(
 	room_version: &RoomVersion,
+	stateres_version: f32,
 	events_to_check: S,
 	unconflicted_state: StateMap<OwnedEventId>,
 	fetch_event: &F,
@@ -538,12 +608,15 @@ where
 		.try_collect()
 		.boxed()
 		.await?;
+	trace!(list = ?events_to_check, "events to check");
 
 	let auth_event_ids: HashSet<OwnedEventId> = events_to_check
 		.iter()
 		.flat_map(|event: &E| event.auth_events().map(ToOwned::to_owned))
 		.collect();
 
+	trace!(set = ?auth_event_ids, "auth event IDs to fetch");
+
 	let auth_events: HashMap<OwnedEventId, E> = auth_event_ids
 		.into_iter()
 		.stream()
@@ -553,9 +626,15 @@ where
 		.boxed()
 		.await;
 
+	trace!(map = ?auth_events.keys().collect::<Vec<_>>(), "fetched auth events");
+
 	let auth_events = &auth_events;
-	let mut resolved_state = unconflicted_state;
+	let mut resolved_state = match stateres_version {
+		| 2.1 => StateMap::new(),
+		| _ => unconflicted_state,
+	};
 	for event in events_to_check {
+		trace!(event_id = event.event_id().as_str(), "checking event");
 		let state_key = event
 			.state_key()
 			.ok_or_else(|| Error::InvalidPdu("State event had no state key".to_owned()))?;
@@ -565,13 +644,29 @@ where
 			event.sender(),
 			Some(state_key),
 			event.content(),
+			room_version,
 		)?;
+		trace!(list = ?auth_types, event_id = event.event_id().as_str(), "auth types for event");
 
 		let mut auth_state = StateMap::new();
+		if room_version.room_ids_as_hashes {
+			trace!("room version uses hashed IDs, manually fetching create event");
+			let create_event_id_raw = event.room_id_or_hash().as_str().replace('!', "$");
+			let create_event_id = EventId::parse(&create_event_id_raw).map_err(|e| {
+				Error::InvalidPdu(format!(
+					"Failed to parse create event ID from room ID/hash: {e}"
+				))
+			})?;
+			let create_event = fetch_event(create_event_id.into())
+				.await
+				.ok_or_else(|| Error::NotFound("Failed to find create event".into()))?;
+			auth_state.insert(create_event.event_type().with_state_key(""), create_event);
+		}
 		for aid in event.auth_events() {
 			if let Some(ev) = auth_events.get(aid) {
 				//TODO: synapse checks "rejected_reason" which is most likely related to
 				// soft-failing
+				trace!(event_id = aid.as_str(), "found auth event");
 				auth_state.insert(
 					ev.event_type()
 						.with_state_key(ev.state_key().ok_or_else(|| {
@@ -600,8 +695,9 @@ where
 				auth_state.insert(key.to_owned(), event);
 			})
 			.await;
+		trace!(map = ?auth_state.keys().collect::<Vec<_>>(), event_id = event.event_id().as_str(), "auth state for event");
 
-		debug!("event to check {:?}", event.event_id());
+		debug!(event_id = event.event_id().as_str(), "Running auth checks");
 
 		// The key for this is (eventType + a state_key of the signed token not sender)
 		// so search for it
@@ -617,16 +713,29 @@ where
 			)
 		};
 
-		let auth_result =
-			auth_check(room_version, &event, current_third_party, fetch_state).await;
+		let auth_result = auth_check(
+			room_version,
+			&event,
+			current_third_party,
+			fetch_state,
+			&fetch_state(&StateEventType::RoomCreate, "")
+				.await
+				.expect("create event must exist"),
+		)
+		.await;
 
 		match auth_result {
 			| Ok(true) => {
 				// add event to resolved state map
+				trace!(
+					event_id = event.event_id().as_str(),
+					"event passed the authentication check, adding to resolved state"
+				);
 				resolved_state.insert(
 					event.event_type().with_state_key(state_key),
 					event.event_id().to_owned(),
 				);
+				trace!(map = ?resolved_state, "new resolved state");
 			},
 			| Ok(false) => {
 				// synapse passes here on AuthError. We do not add this event to resolved_state.
@@ -638,7 +747,8 @@ where
 			},
 		}
 	}
-
+	trace!(map = ?resolved_state, "final resolved state from iterative auth check");
+	debug!("iterative auth check finished");
 	Ok(resolved_state)
 }
 
@@ -909,6 +1019,7 @@ mod tests {
 
 		let resolved_power = super::iterative_auth_check(
 			&RoomVersion::V6,
+			2.1,
 			sorted_power_events.iter().map(AsRef::as_ref).stream(),
 			HashMap::new(), // unconflicted events
 			&fetcher,

src/core/matrix/state_res/room_version.rs

@@ -61,25 +61,34 @@ pub struct RoomVersion {
 	pub extra_redaction_checks: bool,
 	/// Allow knocking in event authentication.
 	///
-	/// See [room v7 specification](https://spec.matrix.org/latest/rooms/v7/) for more information.
+	/// See [room v7 specification](https://spec.matrix.org/latest/rooms/v7/)
 	pub allow_knocking: bool,
 	/// Adds support for the restricted join rule.
 	///
-	/// See: [MSC3289](https://github.com/matrix-org/matrix-spec-proposals/pull/3289) for more information.
+	/// See: [MSC3289](https://github.com/matrix-org/matrix-spec-proposals/pull/3289)
 	pub restricted_join_rules: bool,
 	/// Adds support for the knock_restricted join rule.
 	///
-	/// See: [MSC3787](https://github.com/matrix-org/matrix-spec-proposals/pull/3787) for more information.
+	/// See: [MSC3787](https://github.com/matrix-org/matrix-spec-proposals/pull/3787)
 	pub knock_restricted_join_rule: bool,
 	/// Enforces integer power levels.
 	///
-	/// See: [MSC3667](https://github.com/matrix-org/matrix-spec-proposals/pull/3667) for more information.
+	/// See: [MSC3667](https://github.com/matrix-org/matrix-spec-proposals/pull/3667)
 	pub integer_power_levels: bool,
 	/// Determine the room creator using the `m.room.create` event's `sender`,
 	/// instead of the event content's `creator` field.
 	///
-	/// See: [MSC2175](https://github.com/matrix-org/matrix-spec-proposals/pull/2175) for more information.
+	/// See: [MSC2175](https://github.com/matrix-org/matrix-spec-proposals/pull/2175)
 	pub use_room_create_sender: bool,
+	/// Whether the room creators are considered superusers.
+	/// A superuser will always have infinite power levels in the room.
+	///
+	/// See: [MSC4289](https://github.com/matrix-org/matrix-spec-proposals/pull/4289)
+	pub explicitly_privilege_room_creators: bool,
+	/// Whether the room's m.room.create event ID is itself the room ID.
+	///
+	/// See: [MSC4291](https://github.com/matrix-org/matrix-spec-proposals/pull/4291)
+	pub room_ids_as_hashes: bool,
 }
 
 impl RoomVersion {
@@ -97,6 +106,8 @@ impl RoomVersion {
 		knock_restricted_join_rule: false,
 		integer_power_levels: false,
 		use_room_create_sender: false,
+		explicitly_privilege_room_creators: false,
+		room_ids_as_hashes: false,
 	};
 	pub const V10: Self = Self {
 		knock_restricted_join_rule: true,
@@ -107,6 +118,11 @@ impl RoomVersion {
 		use_room_create_sender: true,
 		..Self::V10
 	};
+	pub const V12: Self = Self {
+		explicitly_privilege_room_creators: true,
+		room_ids_as_hashes: true,
+		..Self::V11
+	};
 	pub const V2: Self = Self {
 		state_res: StateResolutionVersion::V2,
 		..Self::V1
@@ -144,6 +160,7 @@ impl RoomVersion {
 			| RoomVersionId::V9 => Self::V9,
 			| RoomVersionId::V10 => Self::V10,
 			| RoomVersionId::V11 => Self::V11,
+			| RoomVersionId::V12 => Self::V12,
 			| ver => return Err(Error::Unsupported(format!("found version `{ver}`"))),
 		})
 	}

src/core/matrix/state_res/test_utils.rs

@@ -24,7 +24,7 @@ use serde_json::{
 
 use super::auth_types_for_event;
 use crate::{
-	Result, info,
+	Result, RoomVersion, info,
 	matrix::{Event, EventTypeExt, Pdu, StateMap, pdu::EventHash},
 };
 
@@ -154,6 +154,7 @@ pub(crate) async fn do_check(
 			fake_event.sender(),
 			fake_event.state_key(),
 			fake_event.content(),
+			&RoomVersion::V6,
 		)
 		.unwrap();
 
@@ -398,7 +399,7 @@ pub(crate) fn to_init_pdu_event(
 
 	Pdu {
 		event_id: id.try_into().unwrap(),
-		room_id: room_id().to_owned(),
+		room_id: Some(room_id().to_owned()),
 		sender: sender.to_owned(),
 		origin_server_ts: ts.try_into().unwrap(),
 		state_key: state_key.map(Into::into),
@@ -446,7 +447,7 @@ where
 
 	Pdu {
 		event_id: id.try_into().unwrap(),
-		room_id: room_id().to_owned(),
+		room_id: Some(room_id().to_owned()),
 		sender: sender.to_owned(),
 		origin_server_ts: ts.try_into().unwrap(),
 		state_key: state_key.map(Into::into),

src/service/admin/create.rs

@@ -1,6 +1,6 @@
 use std::collections::BTreeMap;
 
-use conduwuit::{Result, pdu::PduBuilder};
+use conduwuit::{Result, info, pdu::PduBuilder};
 use futures::FutureExt;
 use ruma::{
 	RoomId, RoomVersionId,
@@ -26,7 +26,7 @@ use crate::Services;
 /// used to issue admin commands by talking to the server user inside it.
 pub async fn create_admin_room(services: &Services) -> Result {
 	let room_id = RoomId::new(services.globals.server_name());
-	let room_version = &services.config.default_room_version;
+	let room_version = &RoomVersionId::V11;
 
 	let _short_id = services
 		.rooms
@@ -45,10 +45,13 @@ pub async fn create_admin_room(services: &Services) -> Result {
 		match room_version {
 			| V1 | V2 | V3 | V4 | V5 | V6 | V7 | V8 | V9 | V10 =>
 				RoomCreateEventContent::new_v1(server_user.into()),
-			| _ => RoomCreateEventContent::new_v11(),
+			| V11 => RoomCreateEventContent::new_v11(),
+			| _ => RoomCreateEventContent::new_v12(),
 		}
 	};
 
+	info!("Creating admin room {} with version {}", room_id, room_version);
+
 	// 1. The room create event
 	services
 		.rooms
@@ -61,7 +64,7 @@ pub async fn create_admin_room(services: &Services) -> Result {
 				..create_content
 			}),
 			server_user,
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.boxed()
@@ -77,7 +80,7 @@ pub async fn create_admin_room(services: &Services) -> Result {
 				&RoomMemberEventContent::new(MembershipState::Join),
 			),
 			server_user,
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.boxed()
@@ -95,7 +98,7 @@ pub async fn create_admin_room(services: &Services) -> Result {
 				..Default::default()
 			}),
 			server_user,
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.boxed()
@@ -108,7 +111,7 @@ pub async fn create_admin_room(services: &Services) -> Result {
 		.build_and_append_pdu(
 			PduBuilder::state(String::new(), &RoomJoinRulesEventContent::new(JoinRule::Invite)),
 			server_user,
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.boxed()
@@ -124,7 +127,7 @@ pub async fn create_admin_room(services: &Services) -> Result {
 				&RoomHistoryVisibilityEventContent::new(HistoryVisibility::Shared),
 			),
 			server_user,
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.boxed()
@@ -140,7 +143,7 @@ pub async fn create_admin_room(services: &Services) -> Result {
 				&RoomGuestAccessEventContent::new(GuestAccess::Forbidden),
 			),
 			server_user,
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.boxed()
@@ -154,7 +157,7 @@ pub async fn create_admin_room(services: &Services) -> Result {
 		.build_and_append_pdu(
 			PduBuilder::state(String::new(), &RoomNameEventContent::new(room_name)),
 			server_user,
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.boxed()
@@ -168,7 +171,7 @@ pub async fn create_admin_room(services: &Services) -> Result {
 				topic: format!("Manage {} | Run commands prefixed with `!admin` | Run `!admin -h` for help | Documentation: https://continuwuity.org/", services.config.server_name),
 			}),
 			server_user,
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.boxed()
@@ -186,7 +189,7 @@ pub async fn create_admin_room(services: &Services) -> Result {
 				alt_aliases: Vec::new(),
 			}),
 			server_user,
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.boxed()
@@ -204,7 +207,7 @@ pub async fn create_admin_room(services: &Services) -> Result {
 		.build_and_append_pdu(
 			PduBuilder::state(String::new(), &RoomPreviewUrlsEventContent { disabled: true }),
 			server_user,
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.boxed()

src/service/admin/grant.rs

@@ -55,7 +55,7 @@ pub async fn make_user_admin(&self, user_id: &UserId) -> Result {
 					&RoomMemberEventContent::new(MembershipState::Invite),
 				),
 				server_user,
-				&room_id,
+				Some(&room_id),
 				&state_lock,
 			)
 			.await?;
@@ -69,7 +69,7 @@ pub async fn make_user_admin(&self, user_id: &UserId) -> Result {
 					&RoomMemberEventContent::new(MembershipState::Join),
 				),
 				user_id,
-				&room_id,
+				Some(&room_id),
 				&state_lock,
 			)
 			.await?;
@@ -83,7 +83,7 @@ pub async fn make_user_admin(&self, user_id: &UserId) -> Result {
 					&RoomMemberEventContent::new(MembershipState::Invite),
 				),
 				server_user,
-				&room_id,
+				Some(&room_id),
 				&state_lock,
 			)
 			.await?;
@@ -111,7 +111,7 @@ pub async fn make_user_admin(&self, user_id: &UserId) -> Result {
 		.build_and_append_pdu(
 			PduBuilder::state(String::new(), &room_power_levels),
 			server_user,
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.await?;
@@ -135,7 +135,7 @@ pub async fn make_user_admin(&self, user_id: &UserId) -> Result {
 			.build_and_append_pdu(
 				PduBuilder::timeline(&RoomMessageEventContent::text_markdown(welcome_message)),
 				server_user,
-				&room_id,
+				Some(&room_id),
 				&state_lock,
 			)
 			.await?;
@@ -218,7 +218,7 @@ pub async fn revoke_admin(&self, user_id: &UserId) -> Result {
 				..event
 			}),
 			self.services.globals.server_user.as_ref(),
-			&room_id,
+			Some(&room_id),
 			&state_lock,
 		)
 		.await

src/service/admin/mod.rs

@@ -393,13 +393,13 @@ impl Service {
 			return Ok(());
 		};
 
-		let response_sender = if self.is_admin_room(pdu.room_id()).await {
+		let response_sender = if self.is_admin_room(pdu.room_id().unwrap()).await {
 			&self.services.globals.server_user
 		} else {
 			pdu.sender()
 		};
 
-		self.respond_to_room(content, pdu.room_id(), response_sender)
+		self.respond_to_room(content, pdu.room_id().unwrap(), response_sender)
 			.boxed()
 			.await
 	}
@@ -419,7 +419,7 @@ impl Service {
 			.build_and_append_pdu(
 				PduBuilder::timeline(&self.text_or_file(content).await),
 				user_id,
-				room_id,
+				Some(room_id),
 				&state_lock,
 			)
 			.await
@@ -447,7 +447,12 @@ impl Service {
 
 		self.services
 			.timeline
-			.build_and_append_pdu(PduBuilder::timeline(&content), user_id, room_id, state_lock)
+			.build_and_append_pdu(
+				PduBuilder::timeline(&content),
+				user_id,
+				Some(room_id),
+				state_lock,
+			)
 			.await?;
 
 		Ok(())
@@ -484,7 +489,10 @@ impl Service {
 		}
 
 		// Prevent unescaped !admin from being used outside of the admin room
-		if is_public_prefix && !self.is_admin_room(event.room_id()).await {
+		if event.room_id().is_some()
+			&& is_public_prefix
+			&& !self.is_admin_room(event.room_id().unwrap()).await
+		{
 			return false;
 		}
 
@@ -497,7 +505,7 @@ impl Service {
 		// the administrator can execute commands as the server user
 		let emergency_password_set = self.services.server.config.emergency_password.is_some();
 		let from_server = event.sender() == server_user && !emergency_password_set;
-		if from_server && self.is_admin_room(event.room_id()).await {
+		if from_server && self.is_admin_room(event.room_id().unwrap()).await {
 			return false;
 		}
 

src/service/pusher/mod.rs

@@ -287,18 +287,22 @@ impl Service {
 	{
 		let mut notify = None;
 		let mut tweaks = Vec::new();
+		if event.room_id().is_none() {
+			// TODO(hydra): does this matter?
+			return Ok(());
+		}
 
 		let power_levels: RoomPowerLevelsEventContent = self
 			.services
 			.state_accessor
-			.room_state_get(event.room_id(), &StateEventType::RoomPowerLevels, "")
+			.room_state_get(event.room_id().unwrap(), &StateEventType::RoomPowerLevels, "")
 			.await
 			.and_then(|event| event.get_content())
 			.unwrap_or_default();
 
 		let serialized = event.to_format();
 		for action in self
-			.get_actions(user, &ruleset, &power_levels, &serialized, event.room_id())
+			.get_actions(user, &ruleset, &power_levels, &serialized, event.room_id().unwrap())
 			.await
 		{
 			let n = match action {
@@ -426,7 +430,7 @@ impl Service {
 				let mut notifi = Notification::new(d);
 
 				notifi.event_id = Some(event.event_id().to_owned());
-				notifi.room_id = Some(event.room_id().to_owned());
+				notifi.room_id = Some(event.room_id().unwrap().to_owned());
 				if http
 					.data
 					.get("org.matrix.msc4076.disable_badge_count")
@@ -470,14 +474,14 @@ impl Service {
 					notifi.room_name = self
 						.services
 						.state_accessor
-						.get_name(event.room_id())
+						.get_name(event.room_id().unwrap())
 						.await
 						.ok();
 
 					notifi.room_alias = self
 						.services
 						.state_accessor
-						.get_canonical_alias(event.room_id())
+						.get_canonical_alias(event.room_id().unwrap())
 						.await
 						.ok();
 

src/service/rooms/auth_chain/mod.rs

@@ -195,11 +195,11 @@ async fn get_auth_chain_inner(
 				debug_error!(?event_id, ?e, "Could not find pdu mentioned in auth events");
 			},
 			| Ok(pdu) => {
-				if pdu.room_id != room_id {
+				if pdu.room_id.is_some() && pdu.room_id != Some(room_id.to_owned()) {
 					return Err!(Request(Forbidden(error!(
 						?event_id,
 						?room_id,
-						wrong_room_id = ?pdu.room_id,
+						wrong_room_id = ?pdu.room_id.unwrap(),
 						"auth event for incorrect room"
 					))));
 				}

src/service/rooms/event_handler/handle_incoming_pdu.rs

@@ -58,6 +58,10 @@ pub async fn handle_incoming_pdu<'a>(
 	value: BTreeMap<String, CanonicalJsonValue>,
 	is_timeline_event: bool,
 ) -> Result<Option<RawPduId>> {
+	if room_id.is_empty() {
+		// TODO(hydra): Room IDs should be calculated before this function is called
+		panic!("room ID cannot be empty");
+	}
 	// 1. Skip the PDU if we already have it as a timeline event
 	if let Ok(pdu_id) = self.services.timeline.get_pdu_id(event_id).await {
 		return Ok(Some(pdu_id));

src/service/rooms/event_handler/handle_outlier_pdu.rs

@@ -139,6 +139,7 @@ where
 		&pdu_event,
 		None, // TODO: third party invite
 		state_fetch,
+		create_event.as_pdu(),
 	)
 	.await
 	.map_err(|e| err!(Request(Forbidden("Auth check failed: {e:?}"))))?;

src/service/rooms/event_handler/mod.rs

@@ -99,7 +99,10 @@ impl Service {
 }
 
 fn check_room_id<Pdu: Event>(room_id: &RoomId, pdu: &Pdu) -> Result {
-	if pdu.room_id() != room_id {
+	if pdu
+		.room_id()
+		.is_some_and(|claimed_room_id| claimed_room_id != room_id)
+	{
 		return Err!(Request(InvalidParam(error!(
 			pdu_event_id = ?pdu.event_id(),
 			pdu_room_id = ?pdu.room_id(),

src/service/rooms/event_handler/upgrade_outlier_pdu.rs

@@ -102,6 +102,7 @@ where
 		&incoming_pdu,
 		None, // TODO: third party invite
 		|ty, sk| state_fetch(ty.clone(), sk.into()),
+		create_event.as_pdu(),
 	)
 	.await
 	.map_err(|e| err!(Request(Forbidden("Auth check failed: {e:?}"))))?;
@@ -123,6 +124,7 @@ where
 			incoming_pdu.sender(),
 			incoming_pdu.state_key(),
 			incoming_pdu.content(),
+			&room_version,
 		)
 		.await?;
 
@@ -140,6 +142,7 @@ where
 		&incoming_pdu,
 		None, // third-party invite
 		state_fetch,
+		create_event.as_pdu(),
 	)
 	.await
 	.map_err(|e| err!(Request(Forbidden("Auth check failed: {e:?}"))))?;
@@ -156,7 +159,7 @@ where
 			!self
 				.services
 				.state_accessor
-				.user_can_redact(&redact_id, incoming_pdu.sender(), incoming_pdu.room_id(), true)
+				.user_can_redact(&redact_id, incoming_pdu.sender(), room_id, true)
 				.await?,
 	};
 
@@ -313,6 +316,7 @@ where
 				state_ids_compressed,
 				soft_fail,
 				&state_lock,
+				room_id,
 			)
 			.await?;
 
@@ -347,6 +351,7 @@ where
 			state_ids_compressed,
 			soft_fail,
 			&state_lock,
+			room_id,
 		)
 		.await?;
 

src/service/rooms/search/mod.rs

@@ -124,7 +124,7 @@ pub async fn search_pdus<'a>(
 		.wide_filter_map(move |pdu| async move {
 			self.services
 				.state_accessor
-				.user_can_see_event(query.user_id?, pdu.room_id(), pdu.event_id())
+				.user_can_see_event(query.user_id?, pdu.room_id().unwrap(), pdu.event_id())
 				.await
 				.then_some(pdu)
 		})

src/service/rooms/state/mod.rs

@@ -1,6 +1,7 @@
 use std::{collections::HashMap, fmt::Write, iter::once, sync::Arc};
 
 use async_trait::async_trait;
+use conduwuit::{RoomVersion, debug};
 use conduwuit_core::{
 	Event, PduEvent, Result, err,
 	result::FlatOk,
@@ -15,6 +16,7 @@ use conduwuit_database::{Deserialized, Ignore, Interfix, Map};
 use futures::{
 	FutureExt, Stream, StreamExt, TryFutureExt, TryStreamExt, future::join_all, pin_mut,
 };
+use log::trace;
 use ruma::{
 	EventId, OwnedEventId, OwnedRoomId, RoomId, RoomVersionId, UserId,
 	events::{
@@ -148,7 +150,7 @@ impl Service {
 						.roomid_spacehierarchy_cache
 						.lock()
 						.await
-						.remove(&pdu.room_id);
+						.remove(room_id);
 				},
 				| _ => continue,
 			}
@@ -239,7 +241,7 @@ impl Service {
 	/// This adds all current state events (not including the incoming event)
 	/// to `stateid_pduid` and adds the incoming event to `eventid_statehash`.
 	#[tracing::instrument(skip(self, new_pdu), level = "debug")]
-	pub async fn append_to_state(&self, new_pdu: &PduEvent) -> Result<u64> {
+	pub async fn append_to_state(&self, new_pdu: &PduEvent, room_id: &RoomId) -> Result<u64> {
 		const BUFSIZE: usize = size_of::<u64>();
 
 		let shorteventid = self
@@ -248,7 +250,7 @@ impl Service {
 			.get_or_create_shorteventid(&new_pdu.event_id)
 			.await;
 
-		let previous_shortstatehash = self.get_room_shortstatehash(&new_pdu.room_id).await;
+		let previous_shortstatehash = self.get_room_shortstatehash(room_id).await;
 
 		if let Ok(p) = previous_shortstatehash {
 			self.db
@@ -319,7 +321,11 @@ impl Service {
 	}
 
 	#[tracing::instrument(skip_all, level = "debug")]
-	pub async fn summary_stripped<'a, E>(&self, event: &'a E) -> Vec<Raw<AnyStrippedStateEvent>>
+	pub async fn summary_stripped<'a, E>(
+		&self,
+		event: &'a E,
+		room_id: &RoomId,
+	) -> Vec<Raw<AnyStrippedStateEvent>>
 	where
 		E: Event + Send + Sync,
 		&'a E: Event + Send,
@@ -338,7 +344,7 @@ impl Service {
 		let fetches = cells.into_iter().map(|(event_type, state_key)| {
 			self.services
 				.state_accessor
-				.room_state_get(event.room_id(), event_type, state_key)
+				.room_state_get(room_id, event_type, state_key)
 		});
 
 		join_all(fetches)
@@ -421,7 +427,7 @@ impl Service {
 	}
 
 	/// This fetches auth events from the current state.
-	#[tracing::instrument(skip(self, content), level = "debug")]
+	#[tracing::instrument(skip(self, content, room_version), level = "trace")]
 	pub async fn get_auth_events(
 		&self,
 		room_id: &RoomId,
@@ -429,13 +435,15 @@ impl Service {
 		sender: &UserId,
 		state_key: Option<&str>,
 		content: &serde_json::value::RawValue,
+		room_version: &RoomVersion,
 	) -> Result<StateMap<PduEvent>> {
 		let Ok(shortstatehash) = self.get_room_shortstatehash(room_id).await else {
 			return Ok(HashMap::new());
 		};
 
-		let auth_types = state_res::auth_types_for_event(kind, sender, state_key, content)?;
-
+		let auth_types =
+			state_res::auth_types_for_event(kind, sender, state_key, content, room_version)?;
+		debug!(?auth_types, "Auth types for event");
 		let sauthevents: HashMap<_, _> = auth_types
 			.iter()
 			.stream()
@@ -448,6 +456,7 @@ impl Service {
 			})
 			.collect()
 			.await;
+		debug!(?sauthevents, "Auth events to fetch");
 
 		let (state_keys, event_ids): (Vec<_>, Vec<_>) = self
 			.services
@@ -461,7 +470,7 @@ impl Service {
 			})
 			.unzip()
 			.await;
-
+		debug!(?state_keys, ?event_ids, "Auth events found in state");
 		self.services
 			.short
 			.multi_get_eventid_from_short(event_ids.into_iter().stream())
@@ -473,6 +482,7 @@ impl Service {
 					.get_pdu(&event_id)
 					.await
 					.map(move |pdu| (((*ty).clone(), (*sk).clone()), pdu))
+					.inspect_err(|e| warn!("Failed to get auth event {event_id}: {e:?}"))
 					.ok()
 			})
 			.collect()

src/service/rooms/state_accessor/user_can.rs

@@ -161,7 +161,7 @@ pub async fn user_can_invite(
 				&RoomMemberEventContent::new(MembershipState::Invite),
 			),
 			sender,
-			room_id,
+			Some(room_id),
 			state_lock,
 		)
 		.await

src/service/rooms/timeline/append.rs

@@ -42,6 +42,7 @@ pub async fn append_incoming_pdu<'a, Leaves>(
 	state_ids_compressed: Arc<CompressedState>,
 	soft_fail: bool,
 	state_lock: &'a RoomMutexGuard,
+	room_id: &'a ruma::RoomId,
 ) -> Result<Option<RawPduId>>
 where
 	Leaves: Iterator<Item = &'a EventId> + Send + 'a,
@@ -51,24 +52,24 @@ where
 	// fail.
 	self.services
 		.state
-		.set_event_state(&pdu.event_id, &pdu.room_id, state_ids_compressed)
+		.set_event_state(&pdu.event_id, room_id, state_ids_compressed)
 		.await?;
 
 	if soft_fail {
 		self.services
 			.pdu_metadata
-			.mark_as_referenced(&pdu.room_id, pdu.prev_events.iter().map(AsRef::as_ref));
+			.mark_as_referenced(room_id, pdu.prev_events.iter().map(AsRef::as_ref));
 
 		self.services
 			.state
-			.set_forward_extremities(&pdu.room_id, new_room_leaves, state_lock)
+			.set_forward_extremities(room_id, new_room_leaves, state_lock)
 			.await;
 
 		return Ok(None);
 	}
 
 	let pdu_id = self
-		.append_pdu(pdu, pdu_json, new_room_leaves, state_lock)
+		.append_pdu(pdu, pdu_json, new_room_leaves, state_lock, room_id)
 		.await?;
 
 	Ok(Some(pdu_id))
@@ -88,6 +89,7 @@ pub async fn append_pdu<'a, Leaves>(
 	mut pdu_json: CanonicalJsonObject,
 	leaves: Leaves,
 	state_lock: &'a RoomMutexGuard,
+	room_id: &'a ruma::RoomId,
 ) -> Result<RawPduId>
 where
 	Leaves: Iterator<Item = &'a EventId> + Send + 'a,
@@ -98,7 +100,7 @@ where
 	let shortroomid = self
 		.services
 		.short
-		.get_shortroomid(pdu.room_id())
+		.get_shortroomid(room_id)
 		.await
 		.map_err(|_| err!(Database("Room does not exist")))?;
 
@@ -151,14 +153,14 @@ where
 	// We must keep track of all events that have been referenced.
 	self.services
 		.pdu_metadata
-		.mark_as_referenced(pdu.room_id(), pdu.prev_events().map(AsRef::as_ref));
+		.mark_as_referenced(room_id, pdu.prev_events().map(AsRef::as_ref));
 
 	self.services
 		.state
-		.set_forward_extremities(pdu.room_id(), leaves, state_lock)
+		.set_forward_extremities(room_id, leaves, state_lock)
 		.await;
 
-	let insert_lock = self.mutex_insert.lock(pdu.room_id()).await;
+	let insert_lock = self.mutex_insert.lock(room_id).await;
 
 	let count1 = self.services.globals.next_count().unwrap();
 
@@ -166,11 +168,11 @@ where
 	// appending fails
 	self.services
 		.read_receipt
-		.private_read_set(pdu.room_id(), pdu.sender(), count1);
+		.private_read_set(room_id, pdu.sender(), count1);
 
 	self.services
 		.user
-		.reset_notification_counts(pdu.sender(), pdu.room_id());
+		.reset_notification_counts(pdu.sender(), room_id);
 
 	let count2 = PduCount::Normal(self.services.globals.next_count().unwrap());
 	let pdu_id: RawPduId = PduId { shortroomid, shorteventid: count2 }.into();
@@ -184,14 +186,14 @@ where
 	let power_levels: RoomPowerLevelsEventContent = self
 		.services
 		.state_accessor
-		.room_state_get_content(pdu.room_id(), &StateEventType::RoomPowerLevels, "")
+		.room_state_get_content(room_id, &StateEventType::RoomPowerLevels, "")
 		.await
 		.unwrap_or_default();
 
 	let mut push_target: HashSet<_> = self
 			.services
 			.state_cache
-			.active_local_users_in_room(pdu.room_id())
+			.active_local_users_in_room(room_id)
 			.map(ToOwned::to_owned)
 			// Don't notify the sender of their own events, and dont send from ignored users
 			.ready_filter(|user| *user != pdu.sender())
@@ -230,7 +232,7 @@ where
 		for action in self
 			.services
 			.pusher
-			.get_actions(user, &rules_for_user, &power_levels, &serialized, pdu.room_id())
+			.get_actions(user, &rules_for_user, &power_levels, &serialized, room_id)
 			.await
 		{
 			match action {
@@ -268,20 +270,20 @@ where
 	}
 
 	self.db
-		.increment_notification_counts(pdu.room_id(), notifies, highlights);
+		.increment_notification_counts(room_id, notifies, highlights);
 
 	match *pdu.kind() {
 		| TimelineEventType::RoomRedaction => {
 			use RoomVersionId::*;
 
-			let room_version_id = self.services.state.get_room_version(pdu.room_id()).await?;
+			let room_version_id = self.services.state.get_room_version(room_id).await?;
 			match room_version_id {
 				| V1 | V2 | V3 | V4 | V5 | V6 | V7 | V8 | V9 | V10 => {
 					if let Some(redact_id) = pdu.redacts() {
 						if self
 							.services
 							.state_accessor
-							.user_can_redact(redact_id, pdu.sender(), pdu.room_id(), false)
+							.user_can_redact(redact_id, pdu.sender(), room_id, false)
 							.await?
 						{
 							self.redact_pdu(redact_id, pdu, shortroomid).await?;
@@ -294,7 +296,7 @@ where
 						if self
 							.services
 							.state_accessor
-							.user_can_redact(redact_id, pdu.sender(), pdu.room_id(), false)
+							.user_can_redact(redact_id, pdu.sender(), room_id, false)
 							.await?
 						{
 							self.redact_pdu(redact_id, pdu, shortroomid).await?;
@@ -310,7 +312,7 @@ where
 					.roomid_spacehierarchy_cache
 					.lock()
 					.await
-					.remove(pdu.room_id());
+					.remove(room_id);
 			},
 		| TimelineEventType::RoomMember => {
 			if let Some(state_key) = pdu.state_key() {
@@ -320,8 +322,12 @@ where
 
 				let content: RoomMemberEventContent = pdu.get_content()?;
 				let stripped_state = match content.membership {
-					| MembershipState::Invite | MembershipState::Knock =>
-						self.services.state.summary_stripped(pdu).await.into(),
+					| MembershipState::Invite | MembershipState::Knock => self
+						.services
+						.state
+						.summary_stripped(pdu, room_id)
+						.await
+						.into(),
 					| _ => None,
 				};
 
@@ -331,7 +337,7 @@ where
 				self.services
 					.state_cache
 					.update_membership(
-						pdu.room_id(),
+						room_id,
 						target_user_id,
 						content,
 						pdu.sender(),
@@ -392,7 +398,7 @@ where
 		if self
 			.services
 			.state_cache
-			.appservice_in_room(pdu.room_id(), appservice)
+			.appservice_in_room(room_id, appservice)
 			.await
 		{
 			self.services
@@ -430,12 +436,12 @@ where
 		let matching_aliases = |aliases: NamespaceRegex| {
 			self.services
 				.alias
-				.local_aliases_for_room(pdu.room_id())
+				.local_aliases_for_room(room_id)
 				.ready_any(move |room_alias| aliases.is_match(room_alias.as_str()))
 		};
 
 		if matching_aliases(appservice.aliases.clone()).await
-			|| appservice.rooms.is_match(pdu.room_id().as_str())
+			|| appservice.rooms.is_match(room_id.as_str())
 			|| matching_users(&appservice.users)
 		{
 			self.services

src/service/rooms/timeline/build.rs

@@ -1,5 +1,6 @@
 use std::{collections::HashSet, iter::once};
 
+use conduwuit::{RoomVersion, debug_warn, trace};
 use conduwuit_core::{
 	Err, Result, implement,
 	matrix::{event::Event, pdu::PduBuilder},
@@ -11,6 +12,7 @@ use ruma::{
 	events::{
 		TimelineEventType,
 		room::{
+			create::RoomCreateEventContent,
 			member::{MembershipState, RoomMemberEventContent},
 			redaction::RoomRedactionEventContent,
 		},
@@ -23,32 +25,36 @@ use super::RoomMutexGuard;
 /// takes a roomid_mutex_state, meaning that only this function is able to
 /// mutate the room state.
 #[implement(super::Service)]
-#[tracing::instrument(skip(self, state_lock), level = "debug")]
+#[tracing::instrument(skip(self, state_lock), level = "trace")]
 pub async fn build_and_append_pdu(
 	&self,
 	pdu_builder: PduBuilder,
 	sender: &UserId,
-	room_id: &RoomId,
+	room_id: Option<&RoomId>,
 	state_lock: &RoomMutexGuard,
 ) -> Result<OwnedEventId> {
 	let (pdu, pdu_json) = self
 		.create_hash_and_sign_event(pdu_builder, sender, room_id, state_lock)
 		.await?;
 
-	if self.services.admin.is_admin_room(pdu.room_id()).await {
+	let room_id = pdu.room_id_or_hash();
+	trace!("Checking if room {room_id} is an admin room");
+	if self.services.admin.is_admin_room(&room_id).await {
+		trace!("Room {room_id} is an admin room, checking PDU for admin room restrictions");
 		self.check_pdu_for_admin_room(&pdu, sender).boxed().await?;
 	}
 
 	// If redaction event is not authorized, do not append it to the timeline
 	if *pdu.kind() == TimelineEventType::RoomRedaction {
 		use RoomVersionId::*;
-		match self.services.state.get_room_version(pdu.room_id()).await? {
+		trace!("Running redaction checks for room {room_id}");
+		match self.services.state.get_room_version(&room_id).await? {
 			| V1 | V2 | V3 | V4 | V5 | V6 | V7 | V8 | V9 | V10 => {
 				if let Some(redact_id) = pdu.redacts() {
 					if !self
 						.services
 						.state_accessor
-						.user_can_redact(redact_id, pdu.sender(), pdu.room_id(), false)
+						.user_can_redact(redact_id, pdu.sender(), &room_id, false)
 						.await?
 					{
 						return Err!(Request(Forbidden("User cannot redact this event.")));
@@ -61,7 +67,7 @@ pub async fn build_and_append_pdu(
 					if !self
 						.services
 						.state_accessor
-						.user_can_redact(redact_id, pdu.sender(), pdu.room_id(), false)
+						.user_can_redact(redact_id, pdu.sender(), &room_id, false)
 						.await?
 					{
 						return Err!(Request(Forbidden("User cannot redact this event.")));
@@ -72,6 +78,7 @@ pub async fn build_and_append_pdu(
 	}
 
 	if *pdu.kind() == TimelineEventType::RoomMember {
+		trace!("Running room member checks for room {room_id}");
 		let content: RoomMemberEventContent = pdu.get_content()?;
 
 		if content.join_authorized_via_users_server.is_some()
@@ -93,12 +100,27 @@ pub async fn build_and_append_pdu(
 			)));
 		}
 	}
+	if *pdu.kind() == TimelineEventType::RoomCreate {
+		trace!("Running room create checks for room {room_id}");
+		let content: RoomCreateEventContent = pdu.get_content()?;
+		let room_features = RoomVersion::new(&content.room_version)?;
+		if room_features.room_ids_as_hashes {
+			// bootstrap shortid for room
+			debug_warn!(%room_id, "Bootstrapping shortid for room");
+			self.services
+				.short
+				.get_or_create_shortroomid(&room_id)
+				.await;
+		}
+	}
 
 	// We append to state before appending the pdu, so we don't have a moment in
 	// time with the pdu without it's state. This is okay because append_pdu can't
 	// fail.
-	let statehashid = self.services.state.append_to_state(&pdu).await?;
+	trace!("Appending {} state for room {room_id}", pdu.event_id());
+	let statehashid = self.services.state.append_to_state(&pdu, &room_id).await?;
 
+	trace!("Generating raw ID for PDU {}", pdu.event_id());
 	let pdu_id = self
 		.append_pdu(
 			&pdu,
@@ -107,20 +129,22 @@ pub async fn build_and_append_pdu(
 			// of the room
 			once(pdu.event_id()),
 			state_lock,
+			&room_id,
 		)
 		.boxed()
 		.await?;
 
 	// We set the room state after inserting the pdu, so that we never have a moment
 	// in time where events in the current room state do not exist
+	trace!("Setting room state for room {room_id}");
 	self.services
 		.state
-		.set_room_state(pdu.room_id(), statehashid, state_lock);
+		.set_room_state(&room_id, statehashid, state_lock);
 
 	let mut servers: HashSet<OwnedServerName> = self
 		.services
 		.state_cache
-		.room_servers(pdu.room_id())
+		.room_servers(&room_id)
 		.map(ToOwned::to_owned)
 		.collect()
 		.await;
@@ -141,11 +165,13 @@ pub async fn build_and_append_pdu(
 	// room_servers() and/or the if statement above
 	servers.remove(self.services.globals.server_name());
 
+	trace!("Sending PDU {} to {} servers", pdu.event_id(), servers.len());
 	self.services
 		.sending
 		.send_pdu_servers(servers.iter().map(AsRef::as_ref).stream(), &pdu_id)
 		.await?;
 
+	trace!("Event {} in room {:?} has been appended", pdu.event_id(), room_id);
 	Ok(pdu.event_id().to_owned())
 }
 
@@ -179,7 +205,7 @@ where
 					let count = self
 						.services
 						.state_cache
-						.room_members(pdu.room_id())
+						.room_members(&pdu.room_id_or_hash())
 						.ready_filter(|user| self.services.globals.user_is_local(user))
 						.ready_filter(|user| *user != target)
 						.boxed()
@@ -203,7 +229,7 @@ where
 					let count = self
 						.services
 						.state_cache
-						.room_members(pdu.room_id())
+						.room_members(&pdu.room_id_or_hash())
 						.ready_filter(|user| self.services.globals.user_is_local(user))
 						.ready_filter(|user| *user != target)
 						.boxed()

src/service/rooms/timeline/create.rs

@@ -1,5 +1,6 @@
-use std::cmp;
+use std::{cmp, collections::HashMap};
 
+use conduwuit::{smallstr::SmallString, trace};
 use conduwuit_core::{
 	Err, Error, Result, err, implement,
 	matrix::{
@@ -11,12 +12,13 @@ use conduwuit_core::{
 };
 use futures::{StreamExt, TryStreamExt, future, future::ready};
 use ruma::{
-	CanonicalJsonObject, CanonicalJsonValue, OwnedEventId, RoomId, RoomVersionId, UserId,
+	CanonicalJsonObject, CanonicalJsonValue, OwnedEventId, OwnedRoomId, RoomId, RoomVersionId,
+	UserId,
 	canonical_json::to_canonical_value,
 	events::{StateEventType, TimelineEventType, room::create::RoomCreateEventContent},
 	uint,
 };
-use serde_json::value::to_raw_value;
+use serde_json::value::{RawValue, to_raw_value};
 use tracing::warn;
 
 use super::RoomMutexGuard;
@@ -26,10 +28,25 @@ pub async fn create_hash_and_sign_event(
 	&self,
 	pdu_builder: PduBuilder,
 	sender: &UserId,
-	room_id: &RoomId,
+	room_id: Option<&RoomId>,
 	_mutex_lock: &RoomMutexGuard, /* Take mutex guard to make sure users get the room
 	                               * state mutex */
 ) -> Result<(PduEvent, CanonicalJsonObject)> {
+	fn from_evt(
+		room_id: OwnedRoomId,
+		event_type: TimelineEventType,
+		content: Box<RawValue>,
+	) -> Result<RoomVersionId> {
+		if event_type == TimelineEventType::RoomCreate {
+			let content: RoomCreateEventContent = serde_json::from_str(content.get())?;
+			Ok(content.room_version)
+		} else {
+			Err(Error::InconsistentRoomState(
+				"non-create event for room of unknown version",
+				room_id,
+			))
+		}
+	}
 	let PduBuilder {
 		event_type,
 		content,
@@ -38,44 +55,54 @@ pub async fn create_hash_and_sign_event(
 		redacts,
 		timestamp,
 	} = pdu_builder;
-
-	let prev_events: Vec<OwnedEventId> = self
+	// If there was no create event yet, assume we are creating a room
+	let room_version_id = match room_id {
+		| Some(room_id) => self
 			.services
+			.state
+			.get_room_version(room_id)
+			.await
+			.or_else(|_| from_evt(room_id.to_owned(), event_type.clone(), content.clone()))?,
+		| None => from_evt(
+			RoomId::new(self.services.globals.server_name()),
+			event_type.clone(),
+			content.clone(),
+		)?,
+	};
+
+	let room_version = RoomVersion::new(&room_version_id).expect("room version is supported");
+	// TODO(hydra): Only create events can lack a room ID.
+
+	let prev_events: Vec<OwnedEventId> = match room_id {
+		| Some(room_id) =>
+			self.services
 				.state
 				.get_forward_extremities(room_id)
 				.take(20)
 				.map(Into::into)
 				.collect()
-		.await;
+				.await,
+		| None => Vec::new(),
+	};
 
-	// If there was no create event yet, assume we are creating a room
-	let room_version_id = self
-		.services
+	let auth_events: HashMap<(StateEventType, SmallString<[u8; 48]>), PduEvent> = match room_id {
+		| Some(room_id) =>
+			self.services
 				.state
-		.get_room_version(room_id)
-		.await
-		.or_else(|_| {
-			if event_type == TimelineEventType::RoomCreate {
-				let content: RoomCreateEventContent = serde_json::from_str(content.get())?;
-				Ok(content.room_version)
-			} else {
-				Err(Error::InconsistentRoomState(
-					"non-create event for room of unknown version",
-					room_id.to_owned(),
-				))
-			}
-		})?;
-
-	let room_version = RoomVersion::new(&room_version_id).expect("room version is supported");
-
-	let auth_events = self
-		.services
-		.state
-		.get_auth_events(room_id, &event_type, sender, state_key.as_deref(), &content)
-		.await?;
-
+				.get_auth_events(
+					room_id,
+					&event_type,
+					sender,
+					state_key.as_deref(),
+					&content,
+					&room_version,
+				)
+				.await?,
+		| None => HashMap::new(),
+	};
 	// Our depth is the maximum depth of prev_events + 1
-	let depth = prev_events
+	let depth = match room_id {
+		| Some(_) => prev_events
 			.iter()
 			.stream()
 			.map(Ok)
@@ -84,21 +111,28 @@ pub async fn create_hash_and_sign_event(
 			.ignore_err()
 			.ready_fold(uint!(0), cmp::max)
 			.await
-		.saturating_add(uint!(1));
+			.saturating_add(uint!(1)),
+		| None => uint!(1),
+	};
 
 	let mut unsigned = unsigned.unwrap_or_default();
 
+	if let Some(room_id) = room_id {
 		if let Some(state_key) = &state_key {
 			if let Ok(prev_pdu) = self
 				.services
 				.state_accessor
-			.room_state_get(room_id, &event_type.to_string().into(), state_key)
+				.room_state_get(room_id, &event_type.clone().to_string().into(), state_key)
 				.await
 			{
 				unsigned.insert("prev_content".to_owned(), prev_pdu.get_content_as_value());
-			unsigned.insert("prev_sender".to_owned(), serde_json::to_value(prev_pdu.sender())?);
 				unsigned
-				.insert("replaces_state".to_owned(), serde_json::to_value(prev_pdu.event_id())?);
+					.insert("prev_sender".to_owned(), serde_json::to_value(prev_pdu.sender())?);
+				unsigned.insert(
+					"replaces_state".to_owned(),
+					serde_json::to_value(prev_pdu.event_id())?,
+				);
+			}
 		}
 	}
 
@@ -109,15 +143,15 @@ pub async fn create_hash_and_sign_event(
 		// The first two events in a room are always m.room.create and m.room.member,
 		// so any other events with that same depth are illegal.
 		warn!(
-			"Had unsafe depth {depth} when creating non-state event in {room_id}. Cowardly \
-			 aborting"
+			"Had unsafe depth {depth} when creating non-state event in {}. Cowardly aborting",
+			room_id.expect("room_id is Some here").as_str()
 		);
 		return Err!(Request(Unknown("Unsafe depth for non-state event.")));
 	}
 
 	let mut pdu = PduEvent {
 		event_id: ruma::event_id!("$thiswillbefilledinlater").into(),
-		room_id: room_id.to_owned(),
+		room_id: room_id.map(ToOwned::to_owned),
 		sender: sender.to_owned(),
 		origin: None,
 		origin_server_ts: timestamp.map_or_else(
@@ -152,11 +186,30 @@ pub async fn create_hash_and_sign_event(
 		ready(auth_events.get(&key).map(ToOwned::to_owned))
 	};
 
+	let room_id_or_hash = pdu.room_id_or_hash();
+	let create_pdu = match &pdu.kind {
+		| TimelineEventType::RoomCreate => None,
+		| _ => Some(
+			self.services
+				.state_accessor
+				.room_state_get(&room_id_or_hash, &StateEventType::RoomCreate, "")
+				.await
+				.map_err(|e| {
+					err!(Request(Forbidden(warn!("Failed to fetch room create event: {e}"))))
+				})?,
+		),
+	};
+	let create_event = match &pdu.kind {
+		| TimelineEventType::RoomCreate => &pdu,
+		| _ => create_pdu.as_ref().unwrap().as_pdu(),
+	};
+
 	let auth_check = state_res::auth_check(
 		&room_version,
 		&pdu,
 		None, // TODO: third_party_invite
 		auth_fetch,
+		create_event,
 	)
 	.await
 	.map_err(|e| err!(Request(Forbidden(warn!("Auth check failed: {e:?}")))))?;
@@ -164,6 +217,11 @@ pub async fn create_hash_and_sign_event(
 	if !auth_check {
 		return Err!(Request(Forbidden("Event is not authorized.")));
 	}
+	trace!(
+		"Event {} in room {} is authorized",
+		pdu.event_id,
+		pdu.room_id.as_ref().map_or("None", |id| id.as_str())
+	);
 
 	// Hash and sign
 	let mut pdu_json = utils::to_canonical_object(&pdu).map_err(|e| {
@@ -178,13 +236,13 @@ pub async fn create_hash_and_sign_event(
 		},
 	}
 
-	// Add origin because synapse likes that (and it's required in the spec)
 	pdu_json.insert(
 		"origin".to_owned(),
 		to_canonical_value(self.services.globals.server_name())
 			.expect("server name is a valid CanonicalJsonValue"),
 	);
 
+	trace!("hashing and signing event {}", pdu.event_id);
 	if let Err(e) = self
 		.services
 		.server_keys
@@ -204,10 +262,18 @@ pub async fn create_hash_and_sign_event(
 	pdu_json.insert("event_id".into(), CanonicalJsonValue::String(pdu.event_id.clone().into()));
 
 	// Check with the policy server
+	// TODO(hydra): Skip this check for create events (why didnt we do this
+	// already?)
+	if room_id.is_some() {
+		trace!(
+			"Checking event {} in room {} with policy server",
+			pdu.event_id,
+			pdu.room_id.as_ref().map_or("None", |id| id.as_str())
+		);
 		match self
 			.services
 			.event_handler
-		.ask_policy_server(&pdu, room_id)
+			.ask_policy_server(&pdu, &pdu.room_id_or_hash())
 			.await
 		{
 			| Ok(true) => {},
@@ -221,13 +287,20 @@ pub async fn create_hash_and_sign_event(
 				warn!("Failed to check event with policy server: {e}");
 			},
 		}
+	}
 
 	// Generate short event id
+	trace!(
+		"Generating short event ID for {} in room {}",
+		pdu.event_id,
+		pdu.room_id.as_ref().map_or("None", |id| id.as_str())
+	);
 	let _shorteventid = self
 		.services
 		.short
 		.get_or_create_shorteventid(&pdu.event_id)
 		.await;
 
+	trace!("New PDU created: {pdu:?}");
 	Ok((pdu, pdu_json))
 }

src/service/rooms/timeline/redact.rs

@@ -39,7 +39,11 @@ pub async fn redact_pdu<Pdu: Event + Send + Sync>(
 		}
 	}
 
-	let room_version_id = self.services.state.get_room_version(pdu.room_id()).await?;
+	let room_version_id = self
+		.services
+		.state
+		.get_room_version(&pdu.room_id_or_hash())
+		.await?;
 
 	pdu.redact(&room_version_id, reason.to_value())?;
 

src/service/sending/sender.rs

@@ -798,7 +798,7 @@ impl Service {
 			let unread: UInt = self
 				.services
 				.user
-				.notification_count(&user_id, pdu.room_id())
+				.notification_count(&user_id, &pdu.room_id_or_hash())
 				.await
 				.try_into()
 				.expect("notification count can't go that high");

src/service/server_keys/get.rs

@@ -1,6 +1,6 @@
 use std::borrow::Borrow;
 
-use conduwuit::{Err, Result, implement};
+use conduwuit::{Err, Result, debug, debug_error, implement};
 use ruma::{
 	CanonicalJsonObject, RoomVersionId, ServerName, ServerSigningKeyId,
 	api::federation::discovery::VerifyKey,
@@ -19,9 +19,11 @@ pub async fn get_event_keys(
 	let required = match required_keys(object, version) {
 		| Ok(required) => required,
 		| Err(e) => {
+			debug_error!("Failed to determine keys required to verify: {e}");
 			return Err!(BadServerResponse("Failed to determine keys required to verify: {e}"));
 		},
 	};
+	debug!(?required, "Keys required to verify event");
 
 	let batch = required
 		.iter()
@@ -61,6 +63,7 @@ where
 }
 
 #[implement(super::Service)]
+#[tracing::instrument(skip(self))]
 pub async fn get_verify_key(
 	&self,
 	origin: &ServerName,
@@ -70,6 +73,7 @@ pub async fn get_verify_key(
 	let notary_only = self.services.server.config.only_query_trusted_key_servers;
 
 	if let Some(result) = self.verify_keys_for(origin).await.remove(key_id) {
+		debug!("Found key in cache");
 		return Ok(result);
 	}
 

src/service/server_keys/mod.rs

@@ -8,7 +8,7 @@ mod verify;
 use std::{collections::BTreeMap, sync::Arc, time::Duration};
 
 use conduwuit::{
-	Result, Server, implement,
+	Result, Server, debug, debug_error, debug_warn, implement,
 	utils::{IterStream, timepoint_from_now},
 };
 use database::{Deserialized, Json, Map};
@@ -112,6 +112,7 @@ async fn add_signing_keys(&self, new_keys: ServerSigningKeys) {
 }
 
 #[implement(Service)]
+#[tracing::instrument(skip(self, object))]
 pub async fn required_keys_exist(
 	&self,
 	object: &CanonicalJsonObject,
@@ -119,10 +120,12 @@ pub async fn required_keys_exist(
 ) -> bool {
 	use ruma::signatures::required_keys;
 
+	debug!(?object, "Checking required keys exist");
 	let Ok(required_keys) = required_keys(object, version) else {
+		debug_error!("Failed to determine required keys");
 		return false;
 	};
-
+	debug!(?required_keys, "Required keys to verify event");
 	required_keys
 		.iter()
 		.flat_map(|(server, key_ids)| key_ids.iter().map(move |key_id| (server, key_id)))
@@ -132,6 +135,7 @@ pub async fn required_keys_exist(
 }
 
 #[implement(Service)]
+#[tracing::instrument(skip(self))]
 pub async fn verify_key_exists(&self, origin: &ServerName, key_id: &ServerSigningKeyId) -> bool {
 	type KeysMap<'a> = BTreeMap<&'a ServerSigningKeyId, &'a RawJsonValue>;
 
@@ -142,6 +146,7 @@ pub async fn verify_key_exists(&self, origin: &ServerName, key_id: &ServerSignin
 		.await
 		.deserialized::<Raw<ServerSigningKeys>>()
 	else {
+		debug_warn!("No known signing keys found for {origin}");
 		return false;
 	};
 
@@ -157,6 +162,7 @@ pub async fn verify_key_exists(&self, origin: &ServerName, key_id: &ServerSignin
 		}
 	}
 
+	debug_warn!("Key {key_id} not found for {origin}");
 	false
 }
 

src/service/server_keys/verify.rs

@@ -1,4 +1,6 @@
-use conduwuit::{Err, Result, implement, matrix::event::gen_event_id_canonical_json};
+use conduwuit::{
+	Err, Result, debug, debug_warn, implement, matrix::event::gen_event_id_canonical_json,
+};
 use ruma::{
 	CanonicalJsonObject, CanonicalJsonValue, OwnedEventId, RoomVersionId, signatures::Verified,
 };
@@ -28,18 +30,25 @@ pub async fn validate_and_add_event_id_no_fetch(
 	pdu: &RawJsonValue,
 	room_version: &RoomVersionId,
 ) -> Result<(OwnedEventId, CanonicalJsonObject)> {
+	debug!(?pdu, "Validating PDU without fetching keys");
 	let (event_id, mut value) = gen_event_id_canonical_json(pdu, room_version)?;
+	debug!(event_id = event_id.as_str(), "Generated event ID, checking required keys");
 	if !self.required_keys_exist(&value, room_version).await {
+		debug_warn!(
+			"Event {event_id} is missing required keys, cannot verify without fetching keys"
+		);
 		return Err!(BadServerResponse(debug_warn!(
 			"Event {event_id} cannot be verified: missing keys."
 		)));
 	}
-
+	debug!("All required keys exist, verifying event");
 	if let Err(e) = self.verify_event(&value, Some(room_version)).await {
+		debug_warn!("Event verification failed");
 		return Err!(BadServerResponse(debug_error!(
 			"Event {event_id} failed verification: {e:?}"
 		)));
 	}
+	debug!("Event verified successfully");
 
 	value.insert("event_id".into(), CanonicalJsonValue::String(event_id.as_str().into()));
 
@@ -52,7 +61,7 @@ pub async fn verify_event(
 	event: &CanonicalJsonObject,
 	room_version: Option<&RoomVersionId>,
 ) -> Result<Verified> {
-	let room_version = room_version.unwrap_or(&RoomVersionId::V11);
+	let room_version = room_version.unwrap_or(&RoomVersionId::V12);
 	let keys = self.get_event_keys(event, room_version).await?;
 	ruma::signatures::verify_event(&keys, event, room_version).map_err(Into::into)
 }
@@ -63,7 +72,7 @@ pub async fn verify_json(
 	event: &CanonicalJsonObject,
 	room_version: Option<&RoomVersionId>,
 ) -> Result {
-	let room_version = room_version.unwrap_or(&RoomVersionId::V11);
+	let room_version = room_version.unwrap_or(&RoomVersionId::V12);
 	let keys = self.get_event_keys(event, room_version).await?;
 	ruma::signatures::verify_json(&keys, event.clone()).map_err(Into::into)
 }