Add dual_funding cfg flags

Reintroduce the dual_funding cfg flags in the most minimal way possible,
where we just gate the open_channel_v2 and accept_channel_v2 handlers and
wire messages.

Author: dunxen

Cargo.toml

@@ -66,4 +66,5 @@ check-cfg = [
     "cfg(require_route_graph_test)",
     "cfg(splicing)",
     "cfg(async_payments)",
+    "cfg(dual_funding)",
 ]

ci/ci-tests.sh

@@ -136,3 +136,5 @@ RUSTFLAGS="--cfg=trampoline" cargo test --verbose --color always -p lightning
 RUSTFLAGS="--cfg=async_payments" cargo test --verbose --color always -p lightning
 [ "$CI_MINIMIZE_DISK_USAGE" != "" ] && cargo clean
 RUSTFLAGS="--cfg=lsps1_service" cargo test --verbose --color always -p lightning-liquidity
+[ "$CI_MINIMIZE_DISK_USAGE" != "" ] && cargo clean
+RUSTFLAGS="--cfg=dual_funding" cargo test --verbose --color always -p lightning

lightning-net-tokio/src/lib.rs

@@ -743,7 +743,9 @@ mod tests {
 		) {
 		}
 		fn handle_channel_update(&self, _their_node_id: PublicKey, _msg: &ChannelUpdate) {}
+		#[cfg(dual_funding)]
 		fn handle_open_channel_v2(&self, _their_node_id: PublicKey, _msg: &OpenChannelV2) {}
+		#[cfg(dual_funding)]
 		fn handle_accept_channel_v2(&self, _their_node_id: PublicKey, _msg: &AcceptChannelV2) {}
 		fn handle_stfu(&self, _their_node_id: PublicKey, _msg: &Stfu) {}
 		#[cfg(splicing)]

lightning/src/ln/channel.rs

@@ -4576,7 +4576,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
 		})
 	}
 
-	#[cfg(all(test))]
+	#[cfg(all(test, dual_funding))]
 	pub fn get_initial_counterparty_commitment_signature_for_test<L: Deref>(
 		&mut self, funding: &mut FundingScope, logger: &L,
 		counterparty_cur_commitment_point_override: PublicKey,

lightning/src/ln/channelmanager.rs

@@ -1454,6 +1454,7 @@ pub(super) enum OpenChannelMessage {
 
 pub(super) enum OpenChannelMessageRef<'a> {
 	V1(&'a msgs::OpenChannel),
+	#[allow(dead_code)] // TODO(dual_funding): Remove once dual_funding cfg flags removed.
 	V2(&'a msgs::OpenChannelV2),
 }
 
@@ -11650,6 +11651,7 @@ where
 		});
 	}
 
+	#[cfg(dual_funding)]
 	fn handle_open_channel_v2(&self, counterparty_node_id: PublicKey, msg: &msgs::OpenChannelV2) {
 		// Note that we never need to persist the updated ChannelManager for an inbound
 		// open_channel message - pre-funded channels are never written so there should be no
@@ -11678,6 +11680,7 @@ where
 		});
 	}
 
+	#[cfg(dual_funding)]
 	fn handle_accept_channel_v2(&self, counterparty_node_id: PublicKey, msg: &msgs::AcceptChannelV2) {
 		let _: Result<(), _> = handle_error!(self, Err(MsgHandleErrInternal::send_err_msg_no_close(
 			"Dual-funded channels not supported".to_owned(),

lightning/src/ln/dual_funding_tests.rs

@@ -9,6 +9,7 @@
 
 //! Tests that test the creation of dual-funded channels in ChannelManager.
 
+#[cfg(dual_funding)]
 use {
 	crate::chain::chaininterface::{ConfirmationTarget, LowerBoundedFeeEstimator},
 	crate::events::{Event, MessageSendEvent, MessageSendEventsProvider},
@@ -29,13 +30,15 @@ use {
 };
 
 // Dual-funding: V2 Channel Establishment Tests
+#[cfg(dual_funding)]
 struct V2ChannelEstablishmentTestSession {
 	funding_input_sats: u64,
 	initiator_input_value_satoshis: u64,
 }
 
 // TODO(dual_funding): Use real node and API for creating V2 channels as initiator when available,
 // instead of manually constructing messages.
+#[cfg(dual_funding)]
 fn do_test_v2_channel_establishment(session: V2ChannelEstablishmentTestSession) {
 	let chanmon_cfgs = create_chanmon_cfgs(2);
 	let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
@@ -242,6 +245,7 @@ fn do_test_v2_channel_establishment(session: V2ChannelEstablishmentTestSession)
 }
 
 #[test]
+#[cfg(dual_funding)]
 fn test_v2_channel_establishment() {
 	do_test_v2_channel_establishment(V2ChannelEstablishmentTestSession {
 		funding_input_sats: 100_00,

lightning/src/ln/msgs.rs

@@ -1538,10 +1538,12 @@ pub trait ChannelMessageHandler : MessageSendEventsProvider {
 	/// Handle an incoming `open_channel` message from the given peer.
 	fn handle_open_channel(&self, their_node_id: PublicKey, msg: &OpenChannel);
 	/// Handle an incoming `open_channel2` message from the given peer.
+	#[cfg(dual_funding)]
 	fn handle_open_channel_v2(&self, their_node_id: PublicKey, msg: &OpenChannelV2);
 	/// Handle an incoming `accept_channel` message from the given peer.
 	fn handle_accept_channel(&self, their_node_id: PublicKey, msg: &AcceptChannel);
 	/// Handle an incoming `accept_channel2` message from the given peer.
+	#[cfg(dual_funding)]
 	fn handle_accept_channel_v2(&self, their_node_id: PublicKey, msg: &AcceptChannelV2);
 	/// Handle an incoming `funding_created` message from the given peer.
 	fn handle_funding_created(&self, their_node_id: PublicKey, msg: &FundingCreated);

lightning/src/ln/peer_handler.rs

@@ -361,10 +361,12 @@ impl ChannelMessageHandler for ErroringMessageHandler {
 		None
 	}
 
+	#[cfg(dual_funding)]
 	fn handle_open_channel_v2(&self, their_node_id: PublicKey, msg: &msgs::OpenChannelV2) {
 		ErroringMessageHandler::push_error(self, their_node_id, msg.common_fields.temporary_channel_id);
 	}
 
+	#[cfg(dual_funding)]
 	fn handle_accept_channel_v2(&self, their_node_id: PublicKey, msg: &msgs::AcceptChannelV2) {
 		ErroringMessageHandler::push_error(self, their_node_id, msg.common_fields.temporary_channel_id);
 	}
@@ -1832,12 +1834,14 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
 			wire::Message::OpenChannel(msg) => {
 				self.message_handler.chan_handler.handle_open_channel(their_node_id, &msg);
 			},
+			#[cfg(dual_funding)]
 			wire::Message::OpenChannelV2(_msg) => {
 				self.message_handler.chan_handler.handle_open_channel_v2(their_node_id, &_msg);
 			},
 			wire::Message::AcceptChannel(msg) => {
 				self.message_handler.chan_handler.handle_accept_channel(their_node_id, &msg);
 			},
+			#[cfg(dual_funding)]
 			wire::Message::AcceptChannelV2(msg) => {
 				self.message_handler.chan_handler.handle_accept_channel_v2(their_node_id, &msg);
 			},

lightning/src/ln/wire.rs

@@ -57,8 +57,10 @@ pub(crate) enum Message<T: core::fmt::Debug + Type + TestEq> {
 	PeerStorage(msgs::PeerStorage),
 	PeerStorageRetrieval(msgs::PeerStorageRetrieval),
 	OpenChannel(msgs::OpenChannel),
+	#[cfg(dual_funding)]
 	OpenChannelV2(msgs::OpenChannelV2),
 	AcceptChannel(msgs::AcceptChannel),
+	#[cfg(dual_funding)]
 	AcceptChannelV2(msgs::AcceptChannelV2),
 	FundingCreated(msgs::FundingCreated),
 	FundingSigned(msgs::FundingSigned),
@@ -117,8 +119,10 @@ impl<T: core::fmt::Debug + Type + TestEq> Writeable for Message<T> {
 			&Message::PeerStorage(ref msg) => msg.write(writer),
 			&Message::PeerStorageRetrieval(ref msg) => msg.write(writer),
 			&Message::OpenChannel(ref msg) => msg.write(writer),
+			#[cfg(dual_funding)]
 			&Message::OpenChannelV2(ref msg) => msg.write(writer),
 			&Message::AcceptChannel(ref msg) => msg.write(writer),
+			#[cfg(dual_funding)]
 			&Message::AcceptChannelV2(ref msg) => msg.write(writer),
 			&Message::FundingCreated(ref msg) => msg.write(writer),
 			&Message::FundingSigned(ref msg) => msg.write(writer),
@@ -177,8 +181,10 @@ impl<T: core::fmt::Debug + Type + TestEq> Type for Message<T> {
 			&Message::PeerStorage(ref msg) => msg.type_id(),
 			&Message::PeerStorageRetrieval(ref msg) => msg.type_id(),
 			&Message::OpenChannel(ref msg) => msg.type_id(),
+			#[cfg(dual_funding)]
 			&Message::OpenChannelV2(ref msg) => msg.type_id(),
 			&Message::AcceptChannel(ref msg) => msg.type_id(),
+			#[cfg(dual_funding)]
 			&Message::AcceptChannelV2(ref msg) => msg.type_id(),
 			&Message::FundingCreated(ref msg) => msg.type_id(),
 			&Message::FundingSigned(ref msg) => msg.type_id(),
@@ -267,8 +273,10 @@ where
 			Ok(Message::PeerStorageRetrieval(Readable::read(buffer)?))
 		},
 		msgs::OpenChannel::TYPE => Ok(Message::OpenChannel(Readable::read(buffer)?)),
+		#[cfg(dual_funding)]
 		msgs::OpenChannelV2::TYPE => Ok(Message::OpenChannelV2(Readable::read(buffer)?)),
 		msgs::AcceptChannel::TYPE => Ok(Message::AcceptChannel(Readable::read(buffer)?)),
+		#[cfg(dual_funding)]
 		msgs::AcceptChannelV2::TYPE => Ok(Message::AcceptChannelV2(Readable::read(buffer)?)),
 		msgs::FundingCreated::TYPE => Ok(Message::FundingCreated(Readable::read(buffer)?)),
 		msgs::FundingSigned::TYPE => Ok(Message::FundingSigned(Readable::read(buffer)?)),

lightning/src/util/test_utils.rs

@@ -1061,10 +1061,12 @@ impl msgs::ChannelMessageHandler for TestChannelMessageHandler {
 		Some(vec![self.chain_hash])
 	}
 
+	#[cfg(dual_funding)]
 	fn handle_open_channel_v2(&self, _their_node_id: PublicKey, msg: &msgs::OpenChannelV2) {
 		self.received_msg(wire::Message::OpenChannelV2(msg.clone()));
 	}
 
+	#[cfg(dual_funding)]
 	fn handle_accept_channel_v2(&self, _their_node_id: PublicKey, msg: &msgs::AcceptChannelV2) {
 		self.received_msg(wire::Message::AcceptChannelV2(msg.clone()));
 	}