resolve half of the integer_arithmetic lints, couple misc changes

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

Cargo.toml

@@ -625,6 +625,7 @@ manual_let_else = "warn"
 trivially_copy_pass_by_ref = "warn"
 wildcard_imports = "warn"
 checked_conversions = "warn"
+#integer_arithmetic = "warn"
 
 # some sadness
 missing_errors_doc = "allow"

src/api/client_server/account.rs

@@ -1,3 +1,5 @@
+use std::fmt::Write as _;
+
 use register::RegistrationKind;
 use ruma::{
 	api::client::{
@@ -238,7 +240,7 @@ pub(crate) async fn register_route(body: Ruma<register::v3::Request>) -> Result<
 	// If `new_user_displayname_suffix` is set, registration will push whatever
 	// content is set to the user's display name with a space before it
 	if !services().globals.new_user_displayname_suffix().is_empty() {
-		displayname.push_str(&(" ".to_owned() + services().globals.new_user_displayname_suffix()));
+		_ = write!(displayname, " {}", services().globals.config.new_user_displayname_suffix);
 	}
 
 	services()

src/api/client_server/directory.rs

@@ -380,7 +380,12 @@ pub(crate) async fn get_public_rooms_filtered_helper(
 	let next_batch = if chunk.len() < limit as usize {
 		None
 	} else {
-		Some(format!("n{}", num_since + limit))
+		Some(format!(
+			"n{}",
+			num_since
+				.checked_add(limit)
+				.expect("num_since and limit should not be that large")
+		))
 	};
 
 	Ok(get_public_rooms_filtered::v3::Response {

src/api/client_server/keys.rs

@@ -1,4 +1,5 @@
 use std::{
+	cmp,
 	collections::{hash_map, BTreeMap, HashMap, HashSet},
 	time::{Duration, Instant},
 };
@@ -338,7 +339,15 @@ pub(crate) async fn get_keys_helper<F: Fn(&UserId) -> bool>(
 			hash_map::Entry::Vacant(e) => {
 				e.insert((Instant::now(), 1));
 			},
-			hash_map::Entry::Occupied(mut e) => *e.get_mut() = (Instant::now(), e.get().1 + 1),
+			hash_map::Entry::Occupied(mut e) => {
+				*e.get_mut() = (
+					Instant::now(),
+					e.get()
+						.1
+						.checked_add(1)
+						.expect("bad_query_ratelimiter attempt/try count should not ever get this high"),
+				);
+			},
 		}
 	};
 
@@ -353,10 +362,8 @@ pub(crate) async fn get_keys_helper<F: Fn(&UserId) -> bool>(
 				.get(server)
 			{
 				// Exponential backoff
-				let mut min_elapsed_duration = Duration::from_secs(5 * 60) * (*tries) * (*tries);
-				if min_elapsed_duration > Duration::from_secs(60 * 60 * 24) {
-					min_elapsed_duration = Duration::from_secs(60 * 60 * 24);
-				}
+				const MAX_DURATION: Duration = Duration::from_secs(60 * 60 * 24);
+				let min_elapsed_duration = cmp::min(MAX_DURATION, Duration::from_secs(5 * 60) * (*tries) * (*tries));
 
 				if time.elapsed() < min_elapsed_duration {
 					debug!("Backing off query from {:?}", server);

src/api/client_server/membership.rs

@@ -1,4 +1,5 @@
 use std::{
+	cmp,
 	collections::{hash_map::Entry, BTreeMap, HashMap, HashSet},
 	sync::Arc,
 	time::{Duration, Instant},
@@ -1301,8 +1302,8 @@ async fn make_join_request(
 ) -> Result<(federation::membership::prepare_join_event::v1::Response, OwnedServerName)> {
 	let mut make_join_response_and_server = Err(Error::BadServerResponse("No server available to assist in joining."));
 
-	let mut make_join_counter = 0;
-	let mut incompatible_room_version_count = 0;
+	let mut make_join_counter: u16 = 0;
+	let mut incompatible_room_version_count: u8 = 0;
 
 	for remote_server in servers {
 		if server_is_ours(remote_server) {
@@ -1322,7 +1323,7 @@ async fn make_join_request(
 			.await;
 
 		trace!("make_join response: {:?}", make_join_response);
-		make_join_counter += 1;
+		make_join_counter = make_join_counter.saturating_add(1);
 
 		if let Err(ref e) = make_join_response {
 			trace!("make_join ErrorKind string: {:?}", e.error_code().to_string());
@@ -1336,7 +1337,7 @@ async fn make_join_request(
 					.to_string()
 					.contains("M_UNSUPPORTED_ROOM_VERSION")
 			{
-				incompatible_room_version_count += 1;
+				incompatible_room_version_count = incompatible_room_version_count.saturating_add(1);
 			}
 
 			if incompatible_room_version_count > 15 {
@@ -1393,7 +1394,15 @@ async fn validate_and_add_event_id(
 			Entry::Vacant(e) => {
 				e.insert((Instant::now(), 1));
 			},
-			Entry::Occupied(mut e) => *e.get_mut() = (Instant::now(), e.get().1 + 1),
+			Entry::Occupied(mut e) => {
+				*e.get_mut() = (
+					Instant::now(),
+					e.get()
+						.1
+						.checked_add(1)
+						.expect("bad_event_ratelimiter attempt/try count should not ever get this high"),
+				);
+			},
 		}
 	};
 
@@ -1405,10 +1414,8 @@ async fn validate_and_add_event_id(
 		.get(&event_id)
 	{
 		// Exponential backoff
-		let mut min_elapsed_duration = Duration::from_secs(5 * 60) * (*tries) * (*tries);
-		if min_elapsed_duration > Duration::from_secs(60 * 60 * 24) {
-			min_elapsed_duration = Duration::from_secs(60 * 60 * 24);
-		}
+		const MAX_DURATION: Duration = Duration::from_secs(60 * 60 * 24);
+		let min_elapsed_duration = cmp::min(MAX_DURATION, Duration::from_secs(5 * 60) * (*tries) * (*tries));
 
 		if time.elapsed() < min_elapsed_duration {
 			debug!("Backing off from {}", event_id);

src/api/client_server/room.rs

@@ -801,7 +801,13 @@ pub(crate) async fn upgrade_room_route(body: Ruma<upgrade_room::v3::Request>) ->
 	.map_err(|_| Error::bad_database("Invalid room event in database."))?;
 
 	// Setting events_default and invite to the greater of 50 and users_default + 1
-	let new_level = max(int!(50), power_levels_event_content.users_default + int!(1));
+	let new_level = max(
+		int!(50),
+		power_levels_event_content
+			.users_default
+			.checked_add(int!(1))
+			.expect("user power level should not be this high"),
+	);
 	power_levels_event_content.events_default = new_level;
 	power_levels_event_content.invite = new_level;
 

src/api/client_server/search.rs

@@ -106,14 +106,14 @@ pub(crate) async fn search_events_route(body: Ruma<search_events::v3::Request>)
 		}
 	}
 
-	let skip = match body.next_batch.as_ref().map(|s| s.parse()) {
+	let skip: usize = match body.next_batch.as_ref().map(|s| s.parse()) {
 		Some(Ok(s)) => s,
 		Some(Err(_)) => return Err(Error::BadRequest(ErrorKind::InvalidParam, "Invalid next_batch token.")),
 		None => 0, // Default to the start
 	};
 
 	let mut results = Vec::new();
-	for _ in 0..skip + limit {
+	for _ in 0_usize..skip.saturating_add(limit) {
 		if let Some(s) = searches
 			.iter_mut()
 			.map(|s| (s.peek().cloned(), s))
@@ -162,7 +162,7 @@ pub(crate) async fn search_events_route(body: Ruma<search_events::v3::Request>)
 	let next_batch = if results.len() < limit {
 		None
 	} else {
-		Some((skip + limit).to_string())
+		Some((skip.checked_add(limit).unwrap()).to_string())
 	};
 
 	Ok(search_events::v3::Response::new(ResultCategories {

src/api/client_server/sync.rs

@@ -539,7 +539,7 @@ async fn handle_left_room(
 
 	left_state_ids.insert(leave_shortstatekey, left_event_id);
 
-	let mut i = 0;
+	let mut i: u8 = 0;
 	for (key, id) in left_state_ids {
 		if full_state || since_state_ids.get(&key) != Some(&id) {
 			let (event_type, state_key) = services().rooms.short.get_statekey_from_short(key)?;
@@ -557,7 +557,7 @@ async fn handle_left_room(
 
 				left_state_events.push(pdu.to_sync_state_event());
 
-				i += 1;
+				i = i.saturating_add(1);
 				if i % 100 == 0 {
 					tokio::task::yield_now().await;
 				}
@@ -705,7 +705,11 @@ async fn load_joined_room(
 				// Recalculate heroes (first 5 members)
 				let mut heroes = Vec::new();
 
-				if joined_member_count + invited_member_count <= 5 {
+				if joined_member_count
+					.checked_add(invited_member_count)
+					.expect("joined/invite member count should not be this high")
+					<= 5
+				{
 					// Go through all PDUs and for each member event, check if the user is still
 					// joined or invited until we have 5 or we reach the end
 
@@ -784,7 +788,7 @@ async fn load_joined_room(
 				let mut state_events = Vec::new();
 				let mut lazy_loaded = HashSet::new();
 
-				let mut i = 0;
+				let mut i: u8 = 0;
 				for (shortstatekey, id) in current_state_ids {
 					let (event_type, state_key) = services()
 						.rooms
@@ -798,7 +802,7 @@ async fn load_joined_room(
 						};
 						state_events.push(pdu);
 
-						i += 1;
+						i = i.saturating_add(1);
 						if i % 100 == 0 {
 							tokio::task::yield_now().await;
 						}
@@ -819,7 +823,7 @@ async fn load_joined_room(
 						}
 						state_events.push(pdu);
 
-						i += 1;
+						i = i.saturating_add(1);
 						if i % 100 == 0 {
 							tokio::task::yield_now().await;
 						}
@@ -1416,10 +1420,14 @@ pub(crate) async fn sync_events_v4_route(
 					.ranges
 					.into_iter()
 					.map(|mut r| {
-						r.0 =
-							r.0.clamp(uint!(0), UInt::from(all_joined_rooms.len() as u32 - 1));
-						r.1 =
-							r.1.clamp(r.0, UInt::from(all_joined_rooms.len() as u32 - 1));
+						r.0 = r.0.clamp(
+							uint!(0),
+							UInt::try_from(all_joined_rooms.len().saturating_sub(1)).unwrap_or(UInt::MAX),
+						);
+						r.1 = r.1.clamp(
+							r.0,
+							UInt::try_from(all_joined_rooms.len().saturating_sub(1)).unwrap_or(UInt::MAX),
+						);
 						let room_ids = all_joined_rooms[(u64::from(r.0) as usize)..=(u64::from(r.1) as usize)].to_vec();
 						new_known_rooms.extend(room_ids.iter().cloned());
 						for room_id in &room_ids {
@@ -1592,14 +1600,13 @@ pub(crate) async fn sync_events_v4_route(
 			.collect::<Vec<_>>();
 		let name = match heroes.len().cmp(&(1_usize)) {
 			Ordering::Greater => {
+				let firsts = heroes[1..]
+					.iter()
+					.map(|h| h.0.clone())
+					.collect::<Vec<_>>()
+					.join(", ");
 				let last = heroes[0].0.clone();
-				Some(
-					heroes[1..]
-						.iter()
-						.map(|h| h.0.clone())
-						.collect::<Vec<_>>()
-						.join(", ") + " and " + &last,
-				)
+				Some(format!("{firsts} and {last}"))
 			},
 			Ordering::Equal => Some(heroes[0].0.clone()),
 			Ordering::Less => None,

src/api/client_server/typing.rs

@@ -22,14 +22,30 @@ pub(crate) async fn create_typing_event_route(
 
 	if let Typing::Yes(duration) = body.state {
 		let duration = utils::clamp(
-			duration.as_millis() as u64,
-			services().globals.config.typing_client_timeout_min_s * 1000,
-			services().globals.config.typing_client_timeout_max_s * 1000,
+			duration.as_millis().try_into().unwrap_or(u64::MAX),
+			services()
+				.globals
+				.config
+				.typing_client_timeout_min_s
+				.checked_mul(1000)
+				.unwrap(),
+			services()
+				.globals
+				.config
+				.typing_client_timeout_max_s
+				.checked_mul(1000)
+				.unwrap(),
 		);
 		services()
 			.rooms
 			.typing
-			.typing_add(sender_user, &body.room_id, utils::millis_since_unix_epoch() + duration)
+			.typing_add(
+				sender_user,
+				&body.room_id,
+				utils::millis_since_unix_epoch()
+					.checked_add(duration)
+					.expect("user typing timeout should not get this high"),
+			)
 			.await?;
 	} else {
 		services()

src/api/client_server/voip.rs

@@ -21,7 +21,9 @@ pub(crate) async fn turn_server_route(
 
 	let (username, password) = if !turn_secret.is_empty() {
 		let expiry = SecondsSinceUnixEpoch::from_system_time(
-			SystemTime::now() + Duration::from_secs(services().globals.turn_ttl()),
+			SystemTime::now()
+				.checked_add(Duration::from_secs(services().globals.turn_ttl()))
+				.expect("TURN TTL should not get this high"),
 		)
 		.expect("time is valid");
 

src/api/server_server.rs

@@ -101,7 +101,9 @@ pub(crate) async fn get_server_keys_route() -> Result<impl IntoResponse> {
 				old_verify_keys: BTreeMap::new(),
 				signatures: BTreeMap::new(),
 				valid_until_ts: MilliSecondsSinceUnixEpoch::from_system_time(
-					SystemTime::now() + Duration::from_secs(86400 * 7),
+					SystemTime::now()
+						.checked_add(Duration::from_secs(86400 * 7))
+						.expect("valid_until_ts should not get this high"),
 				)
 				.expect("time is valid"),
 			})
@@ -398,8 +400,13 @@ pub(crate) async fn send_transaction_message_route(
 					.is_joined(&typing.user_id, &typing.room_id)?
 				{
 					if typing.typing {
-						let timeout = utils::millis_since_unix_epoch()
-							+ services().globals.config.typing_federation_timeout_s * 1000;
+						let timeout = utils::millis_since_unix_epoch().saturating_add(
+							services()
+								.globals
+								.config
+								.typing_federation_timeout_s
+								.saturating_mul(1000),
+						);
 						services()
 							.rooms
 							.typing
@@ -662,7 +669,7 @@ pub(crate) async fn get_missing_events_route(
 			}
 
 			if body.earliest_events.contains(&queued_events[i]) {
-				i += 1;
+				i = i.saturating_add(1);
 				continue;
 			}
 
@@ -671,7 +678,7 @@ pub(crate) async fn get_missing_events_route(
 				&body.room_id,
 				&queued_events[i],
 			)? {
-				i += 1;
+				i = i.saturating_add(1);
 				continue;
 			}
 
@@ -688,7 +695,7 @@ pub(crate) async fn get_missing_events_route(
 			);
 			events.push(PduEvent::convert_to_outgoing_federation_event(pdu));
 		}
-		i += 1;
+		i = i.saturating_add(1);
 	}
 
 	Ok(get_missing_events::v1::Response {

src/database/key_value/account_data.rs

@@ -105,7 +105,7 @@ impl service::account_data::Data for KeyValueDatabase {
 
 		// Skip the data that's exactly at since, because we sent that last time
 		let mut first_possible = prefix.clone();
-		first_possible.extend_from_slice(&(since + 1).to_be_bytes());
+		first_possible.extend_from_slice(&(since.saturating_add(1)).to_be_bytes());
 
 		for r in self
 			.roomuserdataid_accountdata

src/database/key_value/globals.rs

@@ -158,18 +158,15 @@ impl service::globals::Data for KeyValueDatabase {
 		let max_appservice_in_room_cache = self.appservice_in_room_cache.read().unwrap().capacity();
 		let max_lasttimelinecount_cache = self.lasttimelinecount_cache.lock().unwrap().capacity();
 
-		let mut response = format!(
+		format!(
 			"\
 auth_chain_cache: {auth_chain_cache} / {max_auth_chain_cache}
 our_real_users_cache: {our_real_users_cache} / {max_our_real_users_cache}
 appservice_in_room_cache: {appservice_in_room_cache} / {max_appservice_in_room_cache}
-lasttimelinecount_cache: {lasttimelinecount_cache} / {max_lasttimelinecount_cache}\n\n"
-		);
-		if let Ok(db_stats) = self.db.memory_usage() {
-			response += &db_stats;
-		}
-
-		response
+lasttimelinecount_cache: {lasttimelinecount_cache} / {max_lasttimelinecount_cache}\n\n
+{}",
+			self.db.memory_usage().unwrap_or_default()
+		)
 	}
 
 	fn clear_caches(&self, amount: u32) {

src/database/key_value/rooms/pdu_metadata.rs

@@ -23,10 +23,10 @@ impl service::rooms::pdu_metadata::Data for KeyValueDatabase {
 		let mut current = prefix.clone();
 
 		let count_raw = match until {
-			PduCount::Normal(x) => x - 1,
+			PduCount::Normal(x) => x.saturating_sub(1),
 			PduCount::Backfilled(x) => {
 				current.extend_from_slice(&0_u64.to_be_bytes());
-				u64::MAX - x - 1
+				u64::MAX.saturating_sub(x).saturating_sub(1)
 			},
 		};
 		current.extend_from_slice(&count_raw.to_be_bytes());

src/database/key_value/rooms/read_receipt.rs

@@ -48,7 +48,7 @@ impl service::rooms::read_receipt::Data for KeyValueDatabase {
 		let prefix2 = prefix.clone();
 
 		let mut first_possible_edu = prefix.clone();
-		first_possible_edu.extend_from_slice(&(since + 1).to_be_bytes()); // +1 so we don't send the event at since
+		first_possible_edu.extend_from_slice(&(since.saturating_add(1)).to_be_bytes()); // +1 so we don't send the event at since
 
 		Box::new(
 			self.readreceiptid_readreceipt

src/database/key_value/rooms/state_accessor.rs

@@ -17,7 +17,7 @@ impl service::rooms::state_accessor::Data for KeyValueDatabase {
 			.expect("there is always one layer")
 			.1;
 		let mut result = HashMap::new();
-		let mut i = 0;
+		let mut i: u8 = 0;
 		for compressed in full_state.iter() {
 			let parsed = services()
 				.rooms
@@ -25,7 +25,7 @@ impl service::rooms::state_accessor::Data for KeyValueDatabase {
 				.parse_compressed_state_event(compressed)?;
 			result.insert(parsed.0, parsed.1);
 
-			i += 1;
+			i = i.saturating_add(1);
 			if i % 100 == 0 {
 				tokio::task::yield_now().await;
 			}
@@ -44,7 +44,7 @@ impl service::rooms::state_accessor::Data for KeyValueDatabase {
 			.1;
 
 		let mut result = HashMap::new();
-		let mut i = 0;
+		let mut i: u8 = 0;
 		for compressed in full_state.iter() {
 			let (_, eventid) = services()
 				.rooms
@@ -63,7 +63,7 @@ impl service::rooms::state_accessor::Data for KeyValueDatabase {
 				);
 			}
 
-			i += 1;
+			i = i.saturating_add(1);
 			if i % 100 == 0 {
 				tokio::task::yield_now().await;
 			}

src/database/key_value/rooms/state_cache.rs

@@ -154,11 +154,11 @@ impl service::rooms::state_cache::Data for KeyValueDatabase {
 			if user_is_local(&joined) && !services().users.is_deactivated(&joined).unwrap_or(true) {
 				real_users.insert(joined);
 			}
-			joinedcount += 1;
+			joinedcount = joinedcount.saturating_add(1);
 		}
 
 		for _invited in self.room_members_invited(room_id).filter_map(Result::ok) {
-			invitedcount += 1;
+			invitedcount = invitedcount.saturating_add(1);
 		}
 
 		self.roomid_joinedcount

src/database/key_value/rooms/threads.rs

@@ -19,7 +19,7 @@ impl service::rooms::threads::Data for KeyValueDatabase {
 			.to_vec();
 
 		let mut current = prefix.clone();
-		current.extend_from_slice(&(until - 1).to_be_bytes());
+		current.extend_from_slice(&(until.saturating_sub(1)).to_be_bytes());
 
 		Ok(Box::new(
 			self.threadid_userids

src/database/key_value/rooms/timeline.rs

@@ -256,7 +256,7 @@ fn pdu_count(pdu_id: &[u8]) -> Result<PduCount> {
 		utils::u64_from_bytes(&pdu_id[pdu_id.len() - 2 * size_of::<u64>()..pdu_id.len() - size_of::<u64>()]);
 
 	if matches!(second_last_u64, Ok(0)) {
-		Ok(PduCount::Backfilled(u64::MAX - last_u64))
+		Ok(PduCount::Backfilled(u64::MAX.saturating_sub(last_u64)))
 	} else {
 		Ok(PduCount::Normal(last_u64))
 	}
@@ -275,22 +275,22 @@ fn count_to_id(room_id: &RoomId, count: PduCount, offset: u64, subtract: bool) -
 	let count_raw = match count {
 		PduCount::Normal(x) => {
 			if subtract {
-				x - offset
+				x.saturating_sub(offset)
 			} else {
-				x + offset
+				x.saturating_add(offset)
 			}
 		},
 		PduCount::Backfilled(x) => {
 			pdu_id.extend_from_slice(&0_u64.to_be_bytes());
-			let num = u64::MAX - x;
+			let num = u64::MAX.saturating_sub(x);
 			if subtract {
 				if num > 0 {
-					num - offset
+					num.saturating_sub(offset)
 				} else {
 					num
 				}
 			} else {
-				num + offset
+				num.saturating_add(offset)
 			}
 		},
 	};

src/database/key_value/rooms/user.rs

@@ -110,7 +110,8 @@ impl service::rooms::user::Data for KeyValueDatabase {
 						.enumerate()
 						.find(|(_, &b)| b == 0xFF)
 						.ok_or_else(|| Error::bad_database("Invalid userroomid_joined in db."))?
-						.0 + 1; // +1 because the room id starts AFTER the separator
+						.0
+						.saturating_add(1); // +1 because the room id starts AFTER the separator
 
 					let room_id = key[roomid_index..].to_vec();
 

src/database/key_value/users.rs

@@ -5,7 +5,7 @@ use ruma::{
 	encryption::{CrossSigningKey, DeviceKeys, OneTimeKey},
 	events::{AnyToDeviceEvent, StateEventType},
 	serde::Raw,
-	DeviceId, DeviceKeyAlgorithm, DeviceKeyId, MilliSecondsSinceUnixEpoch, OwnedDeviceId, OwnedDeviceKeyId,
+	uint, DeviceId, DeviceKeyAlgorithm, DeviceKeyId, MilliSecondsSinceUnixEpoch, OwnedDeviceId, OwnedDeviceKeyId,
 	OwnedMxcUri, OwnedUserId, UInt, UserId,
 };
 use tracing::warn;
@@ -414,7 +414,7 @@ impl service::users::Data for KeyValueDatabase {
 					.algorithm(),
 				)
 			}) {
-			*counts.entry(algorithm?).or_default() += UInt::from(1_u32);
+			*counts.entry(algorithm?).or_default() += uint!(1);
 		}
 
 		Ok(counts)
@@ -561,7 +561,7 @@ impl service::users::Data for KeyValueDatabase {
 		prefix.push(0xFF);
 
 		let mut start = prefix.clone();
-		start.extend_from_slice(&(from + 1).to_be_bytes());
+		start.extend_from_slice(&(from.saturating_add(1)).to_be_bytes());
 
 		let to = to.unwrap_or(u64::MAX);
 

src/database/migrations.rs

@@ -173,13 +173,13 @@ pub(crate) async fn migrations(db: &KeyValueDatabase, config: &Config) -> Result
 			let mut current_sstatehash: Option<u64> = None;
 			let mut current_room = None;
 			let mut current_state = HashSet::new();
-			let mut counter = 0;
+			let mut counter: u32 = 0;
 
 			let mut handle_state = |current_sstatehash: u64,
 			                        current_room: &RoomId,
 			                        current_state: HashSet<_>,
 			                        last_roomstates: &mut HashMap<_, _>| {
-				counter += 1;
+				counter = counter.saturating_add(1);
 				let last_roomsstatehash = last_roomstates.get(current_room);
 
 				let states_parents = last_roomsstatehash.map_or_else(

src/database/mod.rs

@@ -401,18 +401,18 @@ impl KeyValueDatabase {
 		let sqlite_exists = path.join("conduit.db").exists();
 		let rocksdb_exists = path.join("IDENTITY").exists();
 
-		let mut count = 0;
+		let mut count: u8 = 0;
 
 		if sqlite_exists {
-			count += 1;
+			count = count.saturating_add(1);
 		}
 
 		if rocksdb_exists {
-			count += 1;
+			count = count.saturating_add(1);
 		}
 
 		if count > 1 {
-			warn!("Multiple databases at database_path detected");
+			error!("Multiple databases at database_path detected");
 			return Ok(());
 		}
 

src/database/rocksdb/opts.rs

@@ -145,7 +145,14 @@ pub(crate) fn cf_options(cfg: &Config, name: &str, mut opts: Options, cache: &mu
 			cache_size(cfg, cfg.statekeyshort_cache_capacity, 1024),
 		),
 
-		"pduid_pdu" => set_table_with_new_cache(&mut opts, cfg, cache, name, cfg.pdu_cache_capacity as usize * 1536),
+		#[allow(clippy::as_conversions, clippy::cast_sign_loss, clippy::cast_possible_truncation)]
+		"pduid_pdu" => set_table_with_new_cache(
+			&mut opts,
+			cfg,
+			cache,
+			name,
+			(cfg.pdu_cache_capacity as usize).saturating_mul(1536),
+		),
 
 		"eventid_outlierpdu" => set_table_with_shared_cache(&mut opts, cfg, cache, name, "pduid_pdu"),
 
@@ -309,7 +316,10 @@ fn set_table_with_shared_cache(
 fn cache_size(config: &Config, base_size: u32, entity_size: usize) -> usize {
 	let ents = f64::from(base_size) * config.conduit_cache_capacity_modifier;
 
-	ents as usize * entity_size
+	#[allow(clippy::as_conversions, clippy::cast_sign_loss, clippy::cast_possible_truncation)]
+	(ents as usize)
+		.checked_mul(entity_size)
+		.expect("cache capacity size is too large")
 }
 
 fn table_options(_config: &Config) -> BlockBasedOptions {

src/service/admin/appservice/appservice_command.rs

@@ -4,7 +4,7 @@ use crate::{service::admin::escape_html, services, Result};
 
 pub(crate) async fn register(body: Vec<&str>) -> Result<RoomMessageEventContent> {
 	if body.len() > 2 && body[0].trim().starts_with("```") && body.last().unwrap().trim() == "```" {
-		let appservice_config = body[1..body.len() - 1].join("\n");
+		let appservice_config = body[1..body.len().checked_sub(1).unwrap()].join("\n");
 		let parsed_config = serde_yaml::from_str::<Registration>(&appservice_config);
 		match parsed_config {
 			Ok(yaml) => match services().appservice.register_appservice(yaml).await {

src/service/admin/debug/debug_commands.rs

@@ -121,7 +121,7 @@ pub(crate) async fn get_remote_pdu_list(
 	if body.len() > 2 && body[0].trim().starts_with("```") && body.last().unwrap().trim() == "```" {
 		let list = body
 			.clone()
-			.drain(1..body.len() - 1)
+			.drain(1..body.len().checked_sub(1).unwrap())
 			.filter_map(|pdu| EventId::parse(pdu).ok())
 			.collect::<Vec<_>>();
 
@@ -381,7 +381,7 @@ pub(crate) async fn change_log_level(
 
 pub(crate) async fn sign_json(body: Vec<&str>) -> Result<RoomMessageEventContent> {
 	if body.len() > 2 && body[0].trim().starts_with("```") && body.last().unwrap().trim() == "```" {
-		let string = body[1..body.len() - 1].join("\n");
+		let string = body[1..body.len().checked_sub(1).unwrap()].join("\n");
 		match serde_json::from_str(&string) {
 			Ok(mut value) => {
 				ruma::signatures::sign_json(
@@ -404,7 +404,7 @@ pub(crate) async fn sign_json(body: Vec<&str>) -> Result<RoomMessageEventContent
 
 pub(crate) async fn verify_json(body: Vec<&str>) -> Result<RoomMessageEventContent> {
 	if body.len() > 2 && body[0].trim().starts_with("```") && body.last().unwrap().trim() == "```" {
-		let string = body[1..body.len() - 1].join("\n");
+		let string = body[1..body.len().checked_sub(1).unwrap()].join("\n");
 		match serde_json::from_str(&string) {
 			Ok(value) => {
 				let pub_key_map = RwLock::new(BTreeMap::new());

src/service/admin/media/media_commands.rs

@@ -139,14 +139,19 @@ pub(crate) async fn delete(
 
 pub(crate) async fn delete_list(body: Vec<&str>) -> Result<RoomMessageEventContent> {
 	if body.len() > 2 && body[0].trim().starts_with("```") && body.last().unwrap().trim() == "```" {
-		let mxc_list = body.clone().drain(1..body.len() - 1).collect::<Vec<_>>();
+		let mxc_list = body
+			.clone()
+			.drain(1..body.len().checked_sub(1).unwrap())
+			.collect::<Vec<_>>();
 
-		let mut mxc_deletion_count = 0;
+		let mut mxc_deletion_count: u32 = 0;
 
 		for mxc in mxc_list {
 			debug!("Deleting MXC {mxc} in bulk");
 			services().media.delete(mxc.to_owned()).await?;
-			mxc_deletion_count += 1;
+			mxc_deletion_count = mxc_deletion_count
+				.checked_add(1)
+				.expect("mxc_deletion_count should not get this high");
 		}
 
 		return Ok(RoomMessageEventContent::text_plain(format!(

src/service/admin/room/room_directory_commands.rs

@@ -39,7 +39,7 @@ pub(crate) async fn process(command: RoomDirectoryCommand, _body: Vec<&str>) ->
 
 			let rooms = rooms
 				.into_iter()
-				.skip(page.saturating_sub(1) * PAGE_SIZE)
+				.skip(page.checked_sub(1).unwrap().checked_mul(PAGE_SIZE).unwrap())
 				.take(PAGE_SIZE)
 				.collect::<Vec<_>>();
 

src/service/admin/server/server_commands.rs

@@ -33,9 +33,9 @@ pub(crate) async fn memory_usage(_body: Vec<&str>) -> Result<RoomMessageEventCon
 	Ok(RoomMessageEventContent::text_plain(format!(
 		"Services:\n{response0}\n\nDatabase:\n{response1}\n{}",
 		if !response2.is_empty() {
-			"Allocator:\n{response2}"
+			format!("Allocator:\n {response2}")
 		} else {
-			""
+			String::new()
 		}
 	)))
 }

src/service/admin/user/user_commands.rs

@@ -61,8 +61,13 @@ pub(crate) async fn create(
 
 	// If `new_user_displayname_suffix` is set, registration will push whatever
 	// content is set to the user's display name with a space before it
-	if !services().globals.new_user_displayname_suffix().is_empty() {
-		displayname.push_str(&(" ".to_owned() + services().globals.new_user_displayname_suffix()));
+	if !services()
+		.globals
+		.config
+		.new_user_displayname_suffix
+		.is_empty()
+	{
+		_ = write!(displayname, " {}", services().globals.config.new_user_displayname_suffix);
 	}
 
 	services()

src/service/globals/client.rs

@@ -89,6 +89,8 @@ impl Client {
 	fn base(config: &Config) -> Result<reqwest::ClientBuilder> {
 		let version = conduwuit_version();
 
+		let user_agent = format!("Conduwuit/{version}");
+
 		let mut builder = reqwest::Client::builder()
 			.hickory_dns(true)
 			.connect_timeout(Duration::from_secs(config.request_conn_timeout))
@@ -96,7 +98,7 @@ impl Client {
 			.timeout(Duration::from_secs(config.request_total_timeout))
 			.pool_idle_timeout(Duration::from_secs(config.request_idle_timeout))
 			.pool_max_idle_per_host(config.request_idle_per_host.into())
-			.user_agent("Conduwuit".to_owned() + "/" + &version)
+			.user_agent(user_agent)
 			.redirect(redirect::Policy::limited(6))
 			.connection_verbose(true);
 

src/service/media/mod.rs

@@ -188,7 +188,7 @@ impl Service {
 				Ok(duration) => {
 					debug!("Parsed duration: {:?}", duration);
 					debug!("System time now: {:?}", SystemTime::now());
-					SystemTime::now() - duration
+					SystemTime::now().checked_sub(duration).unwrap()
 				},
 				Err(e) => {
 					error!("Failed to parse user-specified time duration: {}", e);

src/service/rooms/event_handler/mod.rs

@@ -236,6 +236,7 @@ impl Service {
 			const MAX_DURATION: Duration = Duration::from_secs(60 * 60 * 24);
 			let min_duration = cmp::min(MAX_DURATION, Duration::from_secs(5 * 60) * (*tries) * (*tries));
 			let duration = time.elapsed();
+
 			if duration < min_duration {
 				debug!(
 					duration = ?duration,
@@ -1003,7 +1004,7 @@ impl Service {
 					hash_map::Entry::Vacant(e) => {
 						e.insert((Instant::now(), 1));
 					},
-					hash_map::Entry::Occupied(mut e) => *e.get_mut() = (Instant::now(), e.get().1 + 1),
+					hash_map::Entry::Occupied(mut e) => *e.get_mut() = (Instant::now(), e.get().1.saturating_add(1)),
 				}
 			};
 
@@ -1034,10 +1035,9 @@ impl Service {
 						.get(&*next_id)
 					{
 						// Exponential backoff
-						let mut min_elapsed_duration = Duration::from_secs(5 * 60) * (*tries) * (*tries);
-						if min_elapsed_duration > Duration::from_secs(60 * 60 * 24) {
-							min_elapsed_duration = Duration::from_secs(60 * 60 * 24);
-						}
+						const MAX_DURATION: Duration = Duration::from_secs(60 * 60 * 24);
+						let min_elapsed_duration =
+							cmp::min(MAX_DURATION, Duration::from_secs(5 * 60) * (*tries) * (*tries));
 
 						if time.elapsed() < min_elapsed_duration {
 							info!("Backing off from {}", next_id);
@@ -1143,10 +1143,9 @@ impl Service {
 						.get(&**next_id)
 					{
 						// Exponential backoff
-						let mut min_elapsed_duration = Duration::from_secs(5 * 60) * (*tries) * (*tries);
-						if min_elapsed_duration > Duration::from_secs(60 * 60 * 24) {
-							min_elapsed_duration = Duration::from_secs(60 * 60 * 24);
-						}
+						const MAX_DURATION: Duration = Duration::from_secs(60 * 60 * 24);
+						let min_elapsed_duration =
+							cmp::min(MAX_DURATION, Duration::from_secs(5 * 60) * (*tries) * (*tries));
 
 						if time.elapsed() < min_elapsed_duration {
 							debug!("Backing off from {}", next_id);

src/service/sending/send.rs

@@ -818,7 +818,7 @@ impl FedDest {
 	fn into_uri_string(self) -> String {
 		match self {
 			Self::Literal(addr) => addr.to_string(),
-			Self::Named(host, port) => host + &port,
+			Self::Named(host, port) => format!("{host}{port}"),
 		}
 	}