Stop relying on builder pattern for clearing feature bits

We have a handful of methods to clear features from `*Features`
objects, but have ended up with two different API semantics for
them. In the next commit we'll make them all consistent, opting
against the builder pattern as it turns out all of these lines
utilizing it are too long for rustfmt to be happy, so best to clean
them up now so that rustfmt doesn't make a mockery of our code
later.

Author: TheBlueMatt

lightning-types/src/features.rs

@@ -1040,25 +1040,22 @@ impl<T: sealed::Context> Features<T> {
 
 impl<T: sealed::UpfrontShutdownScript> Features<T> {
 	/// Unsets the `upfront_shutdown_script` feature
-	pub fn clear_upfront_shutdown_script(mut self) -> Self {
+	pub fn clear_upfront_shutdown_script(&mut self) {
 		<T as sealed::UpfrontShutdownScript>::clear_bits(&mut self.flags);
-		self
 	}
 }
 
 impl<T: sealed::ShutdownAnySegwit> Features<T> {
 	/// Unsets the `shutdown_anysegwit` feature
-	pub fn clear_shutdown_anysegwit(mut self) -> Self {
+	pub fn clear_shutdown_anysegwit(&mut self) {
 		<T as sealed::ShutdownAnySegwit>::clear_bits(&mut self.flags);
-		self
 	}
 }
 
 impl<T: sealed::Wumbo> Features<T> {
 	/// Unsets the `wumbo` feature
-	pub fn clear_wumbo(mut self) -> Self {
+	pub fn clear_wumbo(&mut self) {
 		<T as sealed::Wumbo>::clear_bits(&mut self.flags);
-		self
 	}
 }
 

lightning/src/ln/channel.rs

@@ -11241,7 +11241,8 @@ mod tests {
 
 	#[test]
 	fn upfront_shutdown_script_incompatibility() {
-		let features = channelmanager::provided_init_features(&UserConfig::default()).clear_shutdown_anysegwit();
+		let mut features = channelmanager::provided_init_features(&UserConfig::default());
+		features.clear_shutdown_anysegwit();
 		let non_v0_segwit_shutdown_script = ShutdownScript::new_witness_program(
 			&WitnessProgram::new(WitnessVersion::V16, &[0, 40]).unwrap(),
 		).unwrap();

lightning/src/ln/functional_tests.rs

@@ -165,7 +165,9 @@ pub fn test_funding_exceeds_no_wumbo_limit() {
 	use crate::ln::channel::MAX_FUNDING_SATOSHIS_NO_WUMBO;
 	let chanmon_cfgs = create_chanmon_cfgs(2);
 	let mut node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
-	*node_cfgs[1].override_init_features.borrow_mut() = Some(channelmanager::provided_init_features(&test_default_channel_config()).clear_wumbo());
+	let mut features = channelmanager::provided_init_features(&test_default_channel_config());
+	features.clear_wumbo();
+	*node_cfgs[1].override_init_features.borrow_mut() = Some(features);
 	let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
 	let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
 

lightning/src/ln/shutdown_tests.rs

@@ -772,7 +772,9 @@ fn test_upfront_shutdown_script() {
 	}
 
 	// We test that if case of peer non-signaling we don't enforce committed script at channel opening
-	*nodes[0].override_init_features.borrow_mut() = Some(nodes[0].node.init_features().clear_upfront_shutdown_script());
+	let mut features = nodes[0].node.init_features();
+	features.clear_upfront_shutdown_script();
+	*nodes[0].override_init_features.borrow_mut() = Some(features);
 	let chan = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1000000, 1000000);
 	nodes[0].node.close_channel(&chan.2, &nodes[1].node.get_our_node_id()).unwrap();
 	let node_1_shutdown = get_event_msg!(nodes[0], MessageSendEvent::SendShutdown, nodes[1].node.get_our_node_id());
@@ -824,7 +826,9 @@ fn test_unsupported_anysegwit_upfront_shutdown_script() {
 	let chanmon_cfgs = create_chanmon_cfgs(2);
 	let mut node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
 	// Clear shutdown_anysegwit on initiator
-	*node_cfgs[0].override_init_features.borrow_mut() = Some(channelmanager::provided_init_features(&test_default_channel_config()).clear_shutdown_anysegwit());
+	let mut features = channelmanager::provided_init_features(&test_default_channel_config());
+	features.clear_shutdown_anysegwit();
+	*node_cfgs[0].override_init_features.borrow_mut() = Some(features);
 	let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
 	let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
 
@@ -853,7 +857,9 @@ fn test_unsupported_anysegwit_upfront_shutdown_script() {
 	let chanmon_cfgs = create_chanmon_cfgs(2);
 	let mut node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
 	// Clear shutdown_anysegwit on responder
-	*node_cfgs[1].override_init_features.borrow_mut() = Some(channelmanager::provided_init_features(&test_default_channel_config()).clear_shutdown_anysegwit());
+	let mut features = channelmanager::provided_init_features(&test_default_channel_config());
+	features.clear_shutdown_anysegwit();
+	*node_cfgs[1].override_init_features.borrow_mut() = Some(features);
 	let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
 	let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
 
@@ -984,8 +990,10 @@ fn test_unsupported_anysegwit_shutdown_script() {
 	let user_cfgs = [None, Some(config), None];
 	let chanmon_cfgs = create_chanmon_cfgs(3);
 	let mut node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
-	*node_cfgs[0].override_init_features.borrow_mut() = Some(channelmanager::provided_init_features(&config).clear_shutdown_anysegwit());
-	*node_cfgs[1].override_init_features.borrow_mut() = Some(channelmanager::provided_init_features(&config).clear_shutdown_anysegwit());
+	let mut features = channelmanager::provided_init_features(&config);
+	features.clear_shutdown_anysegwit();
+	*node_cfgs[0].override_init_features.borrow_mut() = Some(features.clone());
+	*node_cfgs[1].override_init_features.borrow_mut() = Some(features);
 	let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &user_cfgs);
 	let nodes = create_network(3, &node_cfgs, &node_chanmgrs);