From b915692ae123752fb2102eb7c65a120bdcd3f1cb Mon Sep 17 00:00:00 2001
From: timedout <git@nexy7574.co.uk>
Date: Fri, 10 Jul 2026 16:32:38 +0100
Subject: [PATCH] fix: Remove broken federated invite revoke handling

It turns out it never worked in the first place :D
---
 .../event_handler/handle_incoming_pdu.rs      | 93 +------------------
 src/service/rooms/event_handler/mod.rs        |  4 +-
 2 files changed, 4 insertions(+), 93 deletions(-)

diff --git a/src/service/rooms/event_handler/handle_incoming_pdu.rs b/src/service/rooms/event_handler/handle_incoming_pdu.rs
index 86be9c44b..b5343d825 100644
--- a/src/service/rooms/event_handler/handle_incoming_pdu.rs
+++ b/src/service/rooms/event_handler/handle_incoming_pdu.rs
@@ -4,83 +4,18 @@
 };
 
 use conduwuit::{
-	Err, Event, PduEvent, Result, debug, debug_error, debug_info, debug_warn, defer, err, error,
-	info, matrix::PartialPdu, result::DebugInspect, trace, utils::time::jitter, warn,
+	Err, Event, Result, debug, debug_error, debug_warn, defer, err, error, info,
+	matrix::PartialPdu, result::DebugInspect, trace, utils::time::jitter, warn,
 };
 use futures::{
 	FutureExt, StreamExt,
 	future::{OptionFuture, try_join4},
 };
-use ruma::{
-	CanonicalJsonValue, EventId, OwnedUserId, RoomId, ServerName, UserId,
-	events::{
-		TimelineEventType,
-		room::member::{MembershipState, RoomMemberEventContent},
-	},
-};
+use ruma::{CanonicalJsonValue, EventId, OwnedUserId, RoomId, ServerName, UserId};
 use tokio::sync::mpsc;
 
 use crate::rooms::timeline::{RawPduId, pdu_fits};
 
-async fn should_rescind_invite(
-	services: &crate::rooms::event_handler::Services,
-	content: &mut BTreeMap<String, CanonicalJsonValue>,
-	sender: &UserId,
-	room_id: &RoomId,
-) -> Result<Option<PduEvent>> {
-	// We insert a bogus event ID since we can't actually calculate the right one
-	content.insert("event_id".to_owned(), CanonicalJsonValue::String("$rescind".to_owned()));
-	let pdu_event = serde_json::from_value::<PduEvent>(
-		serde_json::to_value(&content).expect("CanonicalJsonObj is a valid JsonValue"),
-	)
-	.map_err(|e| err!("invalid PDU: {e}"))?;
-
-	if pdu_event.room_id().is_none_or(|r| r != room_id)
-		&& pdu_event.sender() != sender
-		&& pdu_event.event_type() != &TimelineEventType::RoomMember
-		&& pdu_event.state_key().is_none_or(|v| v == sender.as_str())
-	{
-		return Ok(None);
-	}
-
-	let target_user_id = UserId::parse(pdu_event.state_key().unwrap())?;
-	if pdu_event
-		.get_content::<RoomMemberEventContent>()?
-		.membership
-		!= MembershipState::Leave
-	{
-		return Ok(None); // Not a leave event
-	}
-
-	// Does the target user have a pending invite?
-	let Ok(pending_invite_state) = services
-		.state_cache
-		.invite_state(&target_user_id, room_id)
-		.await
-	else {
-		return Ok(None); // No pending invite, so nothing to rescind
-	};
-	for event in pending_invite_state {
-		if event
-			.get_field::<String>("type")?
-			.is_some_and(|t| t == "m.room.member")
-			|| event
-				.get_field::<OwnedUserId>("state_key")?
-				.is_some_and(|s| s == *target_user_id)
-			|| event
-				.get_field::<OwnedUserId>("sender")?
-				.is_some_and(|s| s == *sender)
-			|| event
-				.get_field::<RoomMemberEventContent>("content")?
-				.is_some_and(|c| c.membership == MembershipState::Invite)
-		{
-			return Ok(Some(pdu_event));
-		}
-	}
-
-	Ok(None)
-}
-
 impl super::Service {
 	/// When receiving an event one needs to:
 	/// 0. Check the server is in the room
@@ -183,28 +118,6 @@ pub async fn handle_incoming_pdu<'a>(
 			.server_in_room(self.services.globals.server_name(), room_id)
 			.await
 		{
-			// Is this a federated invite rescind?
-			// copied from https://github.com/element-hq/synapse/blob/7e4588a/synapse/handlers/federation_event.py#L255-L300
-			if value.get("type").and_then(|t| t.as_str()) == Some("m.room.member") {
-				if let Some(pdu) =
-					should_rescind_invite(&self.services, &mut value.clone(), &sender, room_id)
-						.await?
-				{
-					debug_info!(
-						"Invite to {room_id} appears to have been rescinded by {sender}, \
-						 marking as left"
-					);
-
-					self.services
-						.state_cache
-						.mark_as_left(&sender, room_id, Some(pdu))
-						.await;
-
-					self.services.sync.wake(&sender).await;
-
-					return Ok(None);
-				}
-			}
 			info!(
 				%origin,
 				%room_id,
diff --git a/src/service/rooms/event_handler/mod.rs b/src/service/rooms/event_handler/mod.rs
index 1367a2331..9275d1c89 100644
--- a/src/service/rooms/event_handler/mod.rs
+++ b/src/service/rooms/event_handler/mod.rs
@@ -24,7 +24,7 @@
 };
 use tokio::sync::{Notify, mpsc};
 
-use crate::{Dep, globals, rooms, sending, server_keys, sync};
+use crate::{Dep, globals, rooms, sending, server_keys};
 pub struct Service {
 	pub mutex_federation: RoomMutexMap,
 	pub federation_handletime: SyncRwLock<HandleTimeMap>,
@@ -47,7 +47,6 @@ struct Services {
 	state_cache: Dep<rooms::state_cache::Service>,
 	state_accessor: Dep<rooms::state_accessor::Service>,
 	state_compressor: Dep<rooms::state_compressor::Service>,
-	sync: Dep<sync::Service>,
 	timeline: Dep<rooms::timeline::Service>,
 	server: Arc<Server>,
 }
@@ -78,7 +77,6 @@ fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
 					.depend::<rooms::state_accessor::Service>("rooms::state_accessor"),
 				state_compressor: args
 					.depend::<rooms::state_compressor::Service>("rooms::state_compressor"),
-				sync: args.depend::<sync::Service>("sync"),
 				timeline: args.depend::<rooms::timeline::Service>("rooms::timeline"),
 				server: args.server.clone(),
 			},