Cleanup: Remove redundant create_blinded_paths variants

With the recent updates to `create_blinded_paths` supporting
flexible routing through `MessageRouter`, the specialized
variants—`create_compact_blinded_paths` and
`create_blinded_paths_using_absolute_expiry`—have become unnecessary.

This commit removes those now-redundant functions to simplify
the codebase and reduce maintenance overhead.

Author: shaavan

lightning/src/ln/channelmanager.rs

@@ -2868,18 +2868,24 @@ const MAX_PEER_STORAGE_SIZE: usize = 1024;
 /// many peers we reject new (inbound) connections.
 const MAX_NO_CHANNEL_PEERS: usize = 250;
 
+#[cfg(test)]
 /// The maximum expiration from the current time where an [`Offer`] or [`Refund`] is considered
 /// short-lived, while anything with a greater expiration is considered long-lived.
 ///
 /// Using [`ChannelManager::create_offer_builder`] or [`ChannelManager::create_refund_builder`],
-/// will included a [`BlindedMessagePath`] created using:
-/// - [`MessageRouter::create_compact_blinded_paths`] when short-lived, and
-/// - [`MessageRouter::create_blinded_paths`] when long-lived.
+/// will included a [`BlindedMessagePath`] created using [`MessageRouter::create_blinded_paths`].
+///
+/// To generate compact [`BlindedMessagePath`]s:
+/// 1. Parameterize [`ChannelManager`] with a [`MessageRouter`] implementation that always creates
+///    compact paths via [`MessageRouter::create_blinded_paths`].
+/// 2. Use [`ChannelManager::create_offer_builder_using_router`] or
+///    [`ChannelManager::create_refund_builder_using_router`] to provide a custom router that
+///    generates compact paths.
 ///
 /// Using compact [`BlindedMessagePath`]s may provide better privacy as the [`MessageRouter`] could select
 /// more hops. However, since they use short channel ids instead of pubkeys, they are more likely to
 /// become invalid over time as channels are closed. Thus, they are only suitable for short-term use.
-pub const MAX_SHORT_LIVED_RELATIVE_EXPIRY: Duration = Duration::from_secs(60 * 60 * 24);
+pub(super) const MAX_SHORT_LIVED_RELATIVE_EXPIRY: Duration = Duration::from_secs(60 * 60 * 24);
 
 /// Used by [`ChannelManager::list_recent_payments`] to express the status of recent payments.
 /// These include payments that have yet to find a successful path, or have unresolved HTLCs.
@@ -10971,25 +10977,7 @@ where
 		inbound_payment::get_payment_preimage(payment_hash, payment_secret, &self.inbound_payment_key)
 	}
 
-	/// Creates a collection of blinded paths by delegating to [`MessageRouter`] based on
-	/// the path's intended lifetime.
-	///
-	/// Whether or not the path is compact depends on whether the path is short-lived or long-lived,
-	/// respectively, based on the given `absolute_expiry` as seconds since the Unix epoch. See
-	/// [`MAX_SHORT_LIVED_RELATIVE_EXPIRY`].
-	fn create_blinded_paths_using_absolute_expiry(
-		&self, context: OffersContext, absolute_expiry: Option<Duration>,
-	) -> Result<Vec<BlindedMessagePath>, ()> {
-		let now = self.duration_since_epoch();
-		let max_short_lived_absolute_expiry = now.saturating_add(MAX_SHORT_LIVED_RELATIVE_EXPIRY);
-
-		if absolute_expiry.unwrap_or(Duration::MAX) <= max_short_lived_absolute_expiry {
-			self.create_compact_blinded_paths(context)
-		} else {
-			self.create_blinded_paths(MessageContext::Offers(context))
-		}
-	}
-
+	#[cfg(any(test, async_payments))]
 	pub(super) fn duration_since_epoch(&self) -> Duration {
 		#[cfg(not(feature = "std"))]
 		let now = Duration::from_secs(
@@ -11035,21 +11023,6 @@ where
 			.and_then(|paths| (!paths.is_empty()).then(|| paths).ok_or(()))
 	}
 
-	/// Creates a collection of blinded paths by delegating to
-	/// [`MessageRouter::create_compact_blinded_paths`].
-	///
-	/// Errors if the `MessageRouter` errors.
-	fn create_compact_blinded_paths(&self, context: OffersContext) -> Result<Vec<BlindedMessagePath>, ()> {
-		let recipient = self.get_our_node_id();
-		let secp_ctx = &self.secp_ctx;
-
-		let peers = self.get_peers_for_blinded_path();
-
-		self.message_router
-			.create_compact_blinded_paths(recipient, MessageContext::Offers(context), peers, secp_ctx)
-			.and_then(|paths| (!paths.is_empty()).then(|| paths).ok_or(()))
-	}
-
 	/// Creates multi-hop blinded payment paths for the given `amount_msats` by delegating to
 	/// [`Router::create_blinded_payment_paths`].
 	fn create_blinded_payment_paths(

lightning/src/onion_message/messenger.rs

@@ -496,26 +496,6 @@ pub trait MessageRouter {
 		&self, recipient: PublicKey, context: MessageContext, peers: Vec<MessageForwardNode>,
 		secp_ctx: &Secp256k1<T>,
 	) -> Result<Vec<BlindedMessagePath>, ()>;
-
-	/// Creates compact [`BlindedMessagePath`]s to the `recipient` node. The nodes in `peers` are
-	/// assumed to be direct peers with the `recipient`.
-	///
-	/// Compact blinded paths use short channel ids instead of pubkeys for a smaller serialization,
-	/// which is beneficial when a QR code is used to transport the data. The SCID is passed using
-	/// a [`MessageForwardNode`] but may be `None` for graceful degradation.
-	///
-	/// Implementations using additional intermediate nodes are responsible for using a
-	/// [`MessageForwardNode`] with `Some` short channel id, if possible. Similarly, implementations
-	/// should call [`BlindedMessagePath::use_compact_introduction_node`].
-	///
-	/// The provided implementation simply delegates to [`MessageRouter::create_blinded_paths`],
-	/// ignoring the short channel ids.
-	fn create_compact_blinded_paths<T: secp256k1::Signing + secp256k1::Verification>(
-		&self, recipient: PublicKey, context: MessageContext, peers: Vec<MessageForwardNode>,
-		secp_ctx: &Secp256k1<T>,
-	) -> Result<Vec<BlindedMessagePath>, ()> {
-		self.create_blinded_paths(recipient, context, peers, secp_ctx)
-	}
 }
 
 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
@@ -687,21 +667,6 @@ where
 			true,
 		)
 	}
-
-	fn create_compact_blinded_paths<T: secp256k1::Signing + secp256k1::Verification>(
-		&self, recipient: PublicKey, context: MessageContext, peers: Vec<MessageForwardNode>,
-		secp_ctx: &Secp256k1<T>,
-	) -> Result<Vec<BlindedMessagePath>, ()> {
-		Self::create_blinded_paths_from_iter(
-			&self.network_graph,
-			recipient,
-			context,
-			peers.into_iter(),
-			&self.entropy_source,
-			secp_ctx,
-			true,
-		)
-	}
 }
 
 /// This message router is similar to [`DefaultMessageRouter`], but it always creates
@@ -761,21 +726,6 @@ where
 			false,
 		)
 	}
-
-	fn create_compact_blinded_paths<T: secp256k1::Signing + secp256k1::Verification>(
-		&self, recipient: PublicKey, context: MessageContext, peers: Vec<MessageForwardNode>,
-		secp_ctx: &Secp256k1<T>,
-	) -> Result<Vec<BlindedMessagePath>, ()> {
-		DefaultMessageRouter::create_blinded_paths_from_iter(
-			&self.network_graph,
-			recipient,
-			context,
-			peers.into_iter(),
-			&self.entropy_source,
-			secp_ctx,
-			false,
-		)
-	}
 }
 
 /// A special [`MessageRouter`] implementation that performs no routing.
@@ -803,13 +753,6 @@ impl MessageRouter for NullMessageRouter {
 	) -> Result<Vec<BlindedMessagePath>, ()> {
 		Ok(vec![])
 	}
-
-	fn create_compact_blinded_paths<T: secp256k1::Signing + secp256k1::Verification>(
-		&self, _recipient: PublicKey, _context: MessageContext, _peers: Vec<MessageForwardNode>,
-		_secp_ctx: &Secp256k1<T>,
-	) -> Result<Vec<BlindedMessagePath>, ()> {
-		Ok(vec![])
-	}
 }
 
 /// A path for sending an [`OnionMessage`].

lightning/src/util/test_utils.rs

@@ -366,20 +366,6 @@ impl<'a> MessageRouter for TestMessageRouter<'a> {
 			},
 		}
 	}
-
-	fn create_compact_blinded_paths<T: secp256k1::Signing + secp256k1::Verification>(
-		&self, recipient: PublicKey, context: MessageContext, peers: Vec<MessageForwardNode>,
-		secp_ctx: &Secp256k1<T>,
-	) -> Result<Vec<BlindedMessagePath>, ()> {
-		match self {
-			Self::Default { inner } => {
-				inner.create_compact_blinded_paths(recipient, context, peers, secp_ctx)
-			},
-			Self::NodeId { inner } => {
-				inner.create_compact_blinded_paths(recipient, context, peers, secp_ctx)
-			},
-		}
-	}
 }
 
 pub struct OnlyReadsKeysInterface {}