Remove "no-std" feature checks

An upcoming rust-bitcoin release will remove the "no-std" feature.
Replace "no-std" in feature checks with "std", negating as needed. Using
a single feature flag makes the checks more consistent across modules.

Author: jkczyz

lightning/src/ln/channelmanager.rs

@@ -7756,15 +7756,15 @@ where
 				let payment_paths = self.create_blinded_payment_paths(amount_msats, payment_secret)
 					.map_err(|_| Bolt12SemanticError::MissingPaths)?;
 
-				#[cfg(not(feature = "no-std"))]
+				#[cfg(feature = "std")]
 				let builder = refund.respond_using_derived_keys(
 					payment_paths, payment_hash, expanded_key, entropy
 				)?;
-				#[cfg(feature = "no-std")]
+				#[cfg(not(feature = "std"))]
 				let created_at = Duration::from_secs(
 					self.highest_seen_timestamp.load(Ordering::Acquire) as u64
 				);
-				#[cfg(feature = "no-std")]
+				#[cfg(not(feature = "std"))]
 				let builder = refund.respond_using_derived_keys_no_std(
 					payment_paths, payment_hash, created_at, expanded_key, entropy
 				)?;
@@ -9209,17 +9209,17 @@ where
 					},
 				};
 
-				#[cfg(feature = "no-std")]
+				#[cfg(not(feature = "std"))]
 				let created_at = Duration::from_secs(
 					self.highest_seen_timestamp.load(Ordering::Acquire) as u64
 				);
 
 				if invoice_request.keys.is_some() {
-					#[cfg(not(feature = "no-std"))]
+					#[cfg(feature = "std")]
 					let builder = invoice_request.respond_using_derived_keys(
 						payment_paths, payment_hash
 					);
-					#[cfg(feature = "no-std")]
+					#[cfg(not(feature = "std"))]
 					let builder = invoice_request.respond_using_derived_keys_no_std(
 						payment_paths, payment_hash, created_at
 					);
@@ -9228,9 +9228,9 @@ where
 						Err(error) => Some(OffersMessage::InvoiceError(error.into())),
 					}
 				} else {
-					#[cfg(not(feature = "no-std"))]
+					#[cfg(feature = "std")]
 					let builder = invoice_request.respond_with(payment_paths, payment_hash);
-					#[cfg(feature = "no-std")]
+					#[cfg(not(feature = "std"))]
 					let builder = invoice_request.respond_with_no_std(
 						payment_paths, payment_hash, created_at
 					);

lightning/src/ln/outbound_payment.rs

@@ -23,7 +23,7 @@ use crate::routing::router::{InFlightHtlcs, Path, PaymentParameters, Route, Rout
 use crate::util::errors::APIError;
 use crate::util::logger::Logger;
 use crate::util::time::Time;
-#[cfg(all(not(feature = "no-std"), test))]
+#[cfg(all(feature = "std", test))]
 use crate::util::time::tests::SinceEpoch;
 use crate::util::ser::ReadableArgs;
 
@@ -282,21 +282,21 @@ pub enum Retry {
 	/// retry, and may retry multiple failed HTLCs at once if they failed around the same time and
 	/// were retried along a route from a single call to [`Router::find_route_with_id`].
 	Attempts(u32),
-	#[cfg(not(feature = "no-std"))]
+	#[cfg(feature = "std")]
 	/// Time elapsed before abandoning retries for a payment. At least one attempt at payment is made;
 	/// see [`PaymentParameters::expiry_time`] to avoid any attempt at payment after a specific time.
 	///
 	/// [`PaymentParameters::expiry_time`]: crate::routing::router::PaymentParameters::expiry_time
 	Timeout(core::time::Duration),
 }
 
-#[cfg(feature = "no-std")]
+#[cfg(not(feature = "std"))]
 impl_writeable_tlv_based_enum!(Retry,
 	;
 	(0, Attempts)
 );
 
-#[cfg(not(feature = "no-std"))]
+#[cfg(feature = "std")]
 impl_writeable_tlv_based_enum!(Retry,
 	;
 	(0, Attempts),
@@ -309,10 +309,10 @@ impl Retry {
 			(Retry::Attempts(max_retry_count), PaymentAttempts { count, .. }) => {
 				max_retry_count > count
 			},
-			#[cfg(all(not(feature = "no-std"), not(test)))]
+			#[cfg(all(feature = "std", not(test)))]
 			(Retry::Timeout(max_duration), PaymentAttempts { first_attempted_at, .. }) =>
 				*max_duration >= crate::util::time::MonotonicTime::now().duration_since(*first_attempted_at),
-			#[cfg(all(not(feature = "no-std"), test))]
+			#[cfg(all(feature = "std", test))]
 			(Retry::Timeout(max_duration), PaymentAttempts { first_attempted_at, .. }) =>
 				*max_duration >= SinceEpoch::now().duration_since(*first_attempted_at),
 		}
@@ -338,37 +338,37 @@ pub(crate) struct PaymentAttemptsUsingTime<T: Time> {
 	/// it means the result of the first attempt is not known yet.
 	pub(crate) count: u32,
 	/// This field is only used when retry is `Retry::Timeout` which is only build with feature std
-	#[cfg(not(feature = "no-std"))]
+	#[cfg(feature = "std")]
 	first_attempted_at: T,
-	#[cfg(feature = "no-std")]
+	#[cfg(not(feature = "std"))]
 	phantom: core::marker::PhantomData<T>,
 
 }
 
-#[cfg(not(any(feature = "no-std", test)))]
+#[cfg(not(any(not(feature = "std"), test)))]
 type ConfiguredTime = crate::util::time::MonotonicTime;
-#[cfg(feature = "no-std")]
+#[cfg(not(feature = "std"))]
 type ConfiguredTime = crate::util::time::Eternity;
-#[cfg(all(not(feature = "no-std"), test))]
+#[cfg(all(feature = "std", test))]
 type ConfiguredTime = SinceEpoch;
 
 impl<T: Time> PaymentAttemptsUsingTime<T> {
 	pub(crate) fn new() -> Self {
 		PaymentAttemptsUsingTime {
 			count: 0,
-			#[cfg(not(feature = "no-std"))]
+			#[cfg(feature = "std")]
 			first_attempted_at: T::now(),
-			#[cfg(feature = "no-std")]
+			#[cfg(not(feature = "std"))]
 			phantom: core::marker::PhantomData,
 		}
 	}
 }
 
 impl<T: Time> Display for PaymentAttemptsUsingTime<T> {
 	fn fmt(&self, f: &mut Formatter) -> Result<(), fmt::Error> {
-		#[cfg(feature = "no-std")]
+		#[cfg(not(feature = "std"))]
 		return write!(f, "attempts: {}", self.count);
-		#[cfg(not(feature = "no-std"))]
+		#[cfg(feature = "std")]
 		return write!(
 			f,
 			"attempts: {}, duration: {}s",

lightning/src/ln/payment_tests.rs

@@ -44,7 +44,7 @@ use crate::ln::functional_test_utils::*;
 use crate::routing::gossip::NodeId;
 #[cfg(feature = "std")]
 use std::time::{SystemTime, Instant, Duration};
-#[cfg(not(feature = "no-std"))]
+#[cfg(feature = "std")]
 use crate::util::time::tests::SinceEpoch;
 
 #[test]
@@ -2313,7 +2313,7 @@ fn do_automatic_retries(test: AutoRetry) {
 		let mut msg_events = nodes[0].node.get_and_clear_pending_msg_events();
 		assert_eq!(msg_events.len(), 0);
 	} else if test == AutoRetry::FailTimeout {
-		#[cfg(not(feature = "no-std"))] {
+		#[cfg(feature = "std")] {
 			// Ensure ChannelManager will not retry a payment if it times out due to Retry::Timeout.
 			nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
 				PaymentId(payment_hash.0), route_params, Retry::Timeout(Duration::from_secs(60))).unwrap();

lightning/src/routing/gossip.rs

@@ -1845,7 +1845,7 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
 				// NOTE: In the case of no-std, we won't have access to the current UNIX time at the time of removal,
 				// so we'll just set the removal time here to the current UNIX time on the very next invocation
 				// of this function.
-				#[cfg(feature = "no-std")]
+				#[cfg(not(feature = "std"))]
 				{
 					let mut tracked_time = Some(current_time_unix);
 					core::mem::swap(time, &mut tracked_time);

lightning/src/routing/router.rs

@@ -6882,7 +6882,7 @@ mod tests {
 			(route.paths[1].hops[1].short_channel_id == 4 && route.paths[0].hops[1].short_channel_id == 13));
 	}
 
-	#[cfg(not(feature = "no-std"))]
+	#[cfg(feature = "std")]
 	pub(super) fn random_init_seed() -> u64 {
 		// Because the default HashMap in std pulls OS randomness, we can use it as a (bad) RNG.
 		use core::hash::{BuildHasher, Hasher};
@@ -6892,7 +6892,7 @@ mod tests {
 	}
 
 	#[test]
-	#[cfg(not(feature = "no-std"))]
+	#[cfg(feature = "std")]
 	fn generate_routes() {
 		use crate::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParameters};
 
@@ -6913,7 +6913,7 @@ mod tests {
 	}
 
 	#[test]
-	#[cfg(not(feature = "no-std"))]
+	#[cfg(feature = "std")]
 	fn generate_routes_mpp() {
 		use crate::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParameters};
 
@@ -6934,7 +6934,7 @@ mod tests {
 	}
 
 	#[test]
-	#[cfg(not(feature = "no-std"))]
+	#[cfg(feature = "std")]
 	fn generate_large_mpp_routes() {
 		use crate::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParameters};
 
@@ -8270,7 +8270,7 @@ mod tests {
 	}
 }
 
-#[cfg(all(any(test, ldk_bench), not(feature = "no-std")))]
+#[cfg(all(any(test, ldk_bench), feature = "std"))]
 pub(crate) mod bench_utils {
 	use super::*;
 	use std::fs::File;

lightning/src/util/time.rs

@@ -59,15 +59,15 @@ impl Sub<Duration> for Eternity {
 }
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
-#[cfg(not(feature = "no-std"))]
+#[cfg(feature = "std")]
 pub struct MonotonicTime(std::time::Instant);
 
 /// The amount of time to shift `Instant` forward to prevent overflow when subtracting a `Duration`
 /// from `Instant::now` on some operating systems (e.g., iOS representing `Instance` as `u64`).
-#[cfg(not(feature = "no-std"))]
+#[cfg(feature = "std")]
 const SHIFT: Duration = Duration::from_secs(10 * 365 * 24 * 60 * 60); // 10 years.
 
-#[cfg(not(feature = "no-std"))]
+#[cfg(feature = "std")]
 impl Time for MonotonicTime {
 	fn now() -> Self {
 		let instant = std::time::Instant::now().checked_add(SHIFT).expect("Overflow on MonotonicTime instantiation");
@@ -93,7 +93,7 @@ impl Time for MonotonicTime {
 	}
 }
 
-#[cfg(not(feature = "no-std"))]
+#[cfg(feature = "std")]
 impl Sub<Duration> for MonotonicTime {
 	type Output = Self;
 
@@ -177,7 +177,7 @@ pub mod tests {
 	}
 
 	#[test]
-	#[cfg(not(feature = "no-std"))]
+	#[cfg(feature = "std")]
 	fn monotonic_time_subtracts() {
 		let now = super::MonotonicTime::now();
 		assert!(now.elapsed() < Duration::from_secs(10));