only remove event_id field in room v1 and v2

no this doesnt make those rooms work,
just a why not thing

Signed-off-by: strawberry <strawberry@puppygock.gay>

src/api/client_server/membership.rs

@@ -526,9 +526,14 @@ pub(crate) async fn join_room_by_id_helper(
 			.expect("event is valid, we just created it"),
 		);
 
-		// We don't leave the event id in the pdu because that's only allowed in v1 or
+		// We keep the "event_id" in the pdu only in v1 or
 		// v2 rooms
-		join_event_stub.remove("event_id");
+		match room_version_id {
+			RoomVersionId::V1 | RoomVersionId::V2 => {},
+			_ => {
+				join_event_stub.remove("event_id");
+			},
+		};
 
 		// In order to create a compatible ref hash (EventID) the `hashes` field needs
 		// to be present
@@ -929,9 +934,14 @@ pub(crate) async fn join_room_by_id_helper(
 				.expect("event is valid, we just created it"),
 			);
 
-			// We don't leave the event id in the pdu because that's only allowed in v1 or
+			// We keep the "event_id" in the pdu only in v1 or
 			// v2 rooms
-			join_event_stub.remove("event_id");
+			match room_version_id {
+				RoomVersionId::V1 | RoomVersionId::V2 => {},
+				_ => {
+					join_event_stub.remove("event_id");
+				},
+			};
 
 			// In order to create a compatible ref hash (EventID) the `hashes` field needs
 			// to be present
@@ -1419,9 +1429,14 @@ async fn remote_leave_room(user_id: &UserId, room_id: &RoomId) -> Result<()> {
 			utils::millis_since_unix_epoch().try_into().expect("Timestamp is valid js_int value"),
 		),
 	);
-	// We don't leave the event id in the pdu because that's only allowed in v1 or
-	// v2 rooms
-	leave_event_stub.remove("event_id");
+
+	// room v3 and above removed the "event_id" field from remote PDU format
+	match room_version_id {
+		RoomVersionId::V1 | RoomVersionId::V2 => {},
+		_ => {
+			leave_event_stub.remove("event_id");
+		},
+	};
 
 	// In order to create a compatible ref hash (EventID) the `hashes` field needs
 	// to be present

src/api/client_server/room.rs

@@ -202,7 +202,7 @@ pub async fn create_room_route(body: Ruma<create_room::v3::Request>) -> Result<c
 				},
 				RoomVersionId::V11 => {}, // V11 removed the "creator" key
 				_ => {
-					warn!("Unexpected or unsupported room version {}", room_version);
+					warn!("Unexpected or unsupported room version {room_version}");
 					return Err(Error::BadRequest(
 						ErrorKind::BadJson,
 						"Unexpected or unsupported room version found",
@@ -219,7 +219,6 @@ pub async fn create_room_route(body: Ruma<create_room::v3::Request>) -> Result<c
 			content
 		},
 		None => {
-			// TODO: Add correct value for v11
 			let content = match room_version {
 				RoomVersionId::V1
 				| RoomVersionId::V2
@@ -233,7 +232,7 @@ pub async fn create_room_route(body: Ruma<create_room::v3::Request>) -> Result<c
 				| RoomVersionId::V10 => RoomCreateEventContent::new_v1(sender_user.clone()),
 				RoomVersionId::V11 => RoomCreateEventContent::new_v11(),
 				_ => {
-					warn!("Unexpected or unsupported room version {}", room_version);
+					warn!("Unexpected or unsupported room version {room_version}");
 					return Err(Error::BadRequest(
 						ErrorKind::BadJson,
 						"Unexpected or unsupported room version found",

src/api/server_server.rs

@@ -49,7 +49,7 @@ use ruma::{
 	serde::{Base64, JsonObject, Raw},
 	to_device::DeviceIdOrAllDevices,
 	uint, user_id, CanonicalJsonObject, CanonicalJsonValue, EventId, MilliSecondsSinceUnixEpoch, OwnedEventId,
-	OwnedRoomId, OwnedServerName, OwnedServerSigningKeyId, OwnedUserId, RoomId, ServerName,
+	OwnedRoomId, OwnedServerName, OwnedServerSigningKeyId, OwnedUserId, RoomId, RoomVersionId, ServerName,
 };
 use serde_json::value::{to_raw_value, RawValue as RawJsonValue};
 use tokio::sync::RwLock;
@@ -1347,7 +1347,28 @@ pub async fn create_join_event_template_route(
 
 	drop(state_lock);
 
-	pdu_json.remove("event_id");
+	// room v3 and above removed the "event_id" field from remote PDU format
+	match room_version_id {
+		RoomVersionId::V1 | RoomVersionId::V2 => {},
+		RoomVersionId::V3
+		| RoomVersionId::V4
+		| RoomVersionId::V5
+		| RoomVersionId::V6
+		| RoomVersionId::V7
+		| RoomVersionId::V8
+		| RoomVersionId::V9
+		| RoomVersionId::V10
+		| RoomVersionId::V11 => {
+			pdu_json.remove("event_id");
+		},
+		_ => {
+			warn!("Unexpected or unsupported room version {room_version_id}");
+			return Err(Error::BadRequest(
+				ErrorKind::BadJson,
+				"Unexpected or unsupported room version found",
+			));
+		},
+	};
 
 	Ok(prepare_join_event::v1::Response {
 		room_version: Some(room_version_id),

src/service/pdu.rs

@@ -18,7 +18,7 @@ use serde_json::{
 };
 use tracing::warn;
 
-use crate::Error;
+use crate::{services, Error};
 
 /// Content hashes of a PDU.
 #[derive(Clone, Debug, Deserialize, Serialize)]
@@ -281,7 +281,21 @@ impl PduEvent {
 			unsigned.remove("transaction_id");
 		}
 
-		pdu_json.remove("event_id");
+		if let Some(room_id) = pdu_json.get("room_id").and_then(|val| RoomId::parse(val.as_str()?).ok()) {
+			if let Ok(room_version_id) = services().rooms.state.get_room_version(&room_id) {
+				// room v3 and above removed the "event_id" field from remote PDU format
+				match room_version_id {
+					RoomVersionId::V1 | RoomVersionId::V2 => {},
+					_ => {
+						pdu_json.remove("event_id");
+					},
+				};
+			} else {
+				pdu_json.remove("event_id");
+			}
+		} else {
+			pdu_json.remove("event_id");
+		}
 
 		// TODO: another option would be to convert it to a canonical string to validate
 		// size and return a Result<Raw<...>>

src/service/rooms/timeline/mod.rs

@@ -666,7 +666,13 @@ impl Service {
 			Error::bad_database("Failed to convert PDU to canonical JSON.")
 		})?;
 
-		pdu_json.remove("event_id");
+		// room v3 and above removed the "event_id" field from remote PDU format
+		match room_version_id {
+			RoomVersionId::V1 | RoomVersionId::V2 => {},
+			_ => {
+				pdu_json.remove("event_id");
+			},
+		};
 
 		// Add origin because synapse likes that (and it's required in the spec)
 		pdu_json.insert(