From 16f4efa7089292d27e27e49fc5231a58d020aed3 Mon Sep 17 00:00:00 2001
From: Ginger <ginger@gingershaped.computer>
Date: Thu, 4 Sep 2025 10:33:43 -0400
Subject: [PATCH] fix: Fix pagination tokens being corrupted for backfilled
 PDUs

---
 src/api/client/message.rs          |  6 +++---
 src/api/client/relations.rs        |  4 ++--
 src/api/client/threads.rs          |  4 ++--
 src/api/client/utils.rs            | 31 +++++-------------------------
 src/core/matrix/pdu/count.rs       |  6 +++++-
 src/service/rooms/timeline/data.rs |  3 +--
 6 files changed, 18 insertions(+), 36 deletions(-)

diff --git a/src/api/client/message.rs b/src/api/client/message.rs
index f5a951f4..0145b7fe 100644
--- a/src/api/client/message.rs
+++ b/src/api/client/message.rs
@@ -35,7 +35,7 @@ use ruma::{
 };
 use tracing::warn;
 
-use super::utils::{count_to_token, parse_pagination_token as parse_token};
+use super::utils::{count_to_pagination_token, pagination_token_to_count as parse_token};
 use crate::Ruma;
 
 /// list of safe and common non-state events to ignore if the user is ignored
@@ -181,8 +181,8 @@ pub(crate) async fn get_message_events_route(
 		.collect();
 
 	Ok(get_message_events::v3::Response {
-		start: count_to_token(from),
-		end: next_token.map(count_to_token),
+		start: count_to_pagination_token(from),
+		end: next_token.map(count_to_pagination_token),
 		chunk,
 		state,
 	})
diff --git a/src/api/client/relations.rs b/src/api/client/relations.rs
index f6d8fe9e..f2ec3f23 100644
--- a/src/api/client/relations.rs
+++ b/src/api/client/relations.rs
@@ -18,7 +18,7 @@ use ruma::{
 	events::{TimelineEventType, relation::RelationType},
 };
 
-use super::utils::{count_to_token, parse_pagination_token as parse_token};
+use super::utils::{count_to_pagination_token, pagination_token_to_count as parse_token};
 use crate::Ruma;
 
 /// # `GET /_matrix/client/r0/rooms/{roomId}/relations/{eventId}/{relType}/{eventType}`
@@ -193,7 +193,7 @@ async fn paginate_relations_with_filter(
 			| Direction::Forward => events.last(),
 			| Direction::Backward => events.first(),
 		}
-		.map(|(count, _)| count_to_token(*count))
+		.map(|(count, _)| count_to_pagination_token(*count))
 	} else {
 		None
 	};
diff --git a/src/api/client/threads.rs b/src/api/client/threads.rs
index ca176eda..f0fb4a64 100644
--- a/src/api/client/threads.rs
+++ b/src/api/client/threads.rs
@@ -9,7 +9,7 @@ use conduwuit::{
 use futures::StreamExt;
 use ruma::{api::client::threads::get_threads, uint};
 
-use crate::Ruma;
+use crate::{Ruma, client::utils::pagination_token_to_count};
 
 /// # `GET /_matrix/client/r0/rooms/{roomId}/threads`
 pub(crate) async fn get_threads_route(
@@ -27,7 +27,7 @@ pub(crate) async fn get_threads_route(
 	let from: PduCount = body
 		.from
 		.as_deref()
-		.map(str::parse)
+		.map(pagination_token_to_count)
 		.transpose()?
 		.unwrap_or_else(PduCount::max);
 
diff --git a/src/api/client/utils.rs b/src/api/client/utils.rs
index cc941b95..ec69388a 100644
--- a/src/api/client/utils.rs
+++ b/src/api/client/utils.rs
@@ -1,28 +1,7 @@
-use conduwuit::{
-	Result, err,
-	matrix::pdu::{PduCount, ShortEventId},
-};
+use conduwuit::{Result, matrix::pdu::PduCount};
 
-/// Parse a pagination token, trying ShortEventId first, then falling back to
-/// PduCount
-pub(crate) fn parse_pagination_token(token: &str) -> Result<PduCount> {
-	// Try parsing as ShortEventId first
-	if let Ok(shorteventid) = token.parse::<ShortEventId>() {
-		// ShortEventId maps directly to a PduCount in our database
-		Ok(PduCount::Normal(shorteventid))
-	} else if let Ok(count) = token.parse::<u64>() {
-		// Fallback to PduCount for backwards compatibility
-		Ok(PduCount::Normal(count))
-	} else if let Ok(count) = token.parse::<i64>() {
-		// Also handle negative counts for backfilled events
-		Ok(PduCount::from_signed(count))
-	} else {
-		Err(err!(Request(InvalidParam("Invalid pagination token"))))
-	}
-}
+/// Parse a pagination token
+pub(crate) fn pagination_token_to_count(token: &str) -> Result<PduCount> { token.parse() }
 
-/// Convert a PduCount to a token string (using the underlying ShortEventId)
-pub(crate) fn count_to_token(count: PduCount) -> String {
-	// The PduCount's unsigned value IS the ShortEventId
-	count.into_unsigned().to_string()
-}
+/// Convert a PduCount to a token string
+pub(crate) fn count_to_pagination_token(count: PduCount) -> String { count.to_string() }
diff --git a/src/core/matrix/pdu/count.rs b/src/core/matrix/pdu/count.rs
index b880278f..7fb12574 100644
--- a/src/core/matrix/pdu/count.rs
+++ b/src/core/matrix/pdu/count.rs
@@ -1,6 +1,10 @@
 #![allow(clippy::cast_possible_wrap, clippy::cast_sign_loss, clippy::as_conversions)]
 
-use std::{cmp::Ordering, fmt, fmt::Display, str::FromStr};
+use std::{
+	cmp::Ordering,
+	fmt::{self, Display},
+	str::FromStr,
+};
 
 use ruma::api::Direction;
 
diff --git a/src/service/rooms/timeline/data.rs b/src/service/rooms/timeline/data.rs
index fa10a5c0..9064df6c 100644
--- a/src/service/rooms/timeline/data.rs
+++ b/src/service/rooms/timeline/data.rs
@@ -3,8 +3,7 @@ use std::{borrow::Borrow, sync::Arc};
 use conduwuit::{
 	Err, PduCount, PduEvent, Result, at, err,
 	result::{LogErr, NotFound},
-	utils,
-	utils::stream::TryReadyExt,
+	utils::{self, stream::TryReadyExt},
 };
 use database::{Database, Deserialized, Json, KeyVal, Map};
 use futures::{FutureExt, Stream, TryFutureExt, TryStreamExt, future::select_ok, pin_mut};