Make router benchmarks more realistic by not running test-only code

`cargo bench` sets `cfg(test)`, causing us to hit some test-only
code in the router when benchmarking, throwing off our benchmarks
substantially. Here we swap from the `unstable` feature to a more
clearly internal feature (`_bench_unstable`) and also checking for
it when enabling test-only code.

.github/workflows/build.yml

@@ -231,7 +231,7 @@ jobs:
           cd ..
       - name: Run benchmarks on Rust ${{ matrix.toolchain }}
         run: |
-          cargo bench --features unstable
+          cargo bench --features _bench_unstable
 
   check_commits:
     runs-on: ubuntu-latest

lightning-persister/Cargo.toml

@@ -9,7 +9,7 @@ Utilities to manage Rust-Lightning channel data persistence and retrieval.
 """
 
 [features]
-unstable = ["lightning/unstable"]
+_bench_unstable = ["lightning/_bench_unstable"]
 
 [dependencies]
 bitcoin = "0.27"

lightning-persister/src/lib.rs

@@ -3,8 +3,8 @@
 #![deny(broken_intra_doc_links)]
 #![deny(missing_docs)]
 
-#![cfg_attr(all(test, feature = "unstable"), feature(test))]
-#[cfg(all(test, feature = "unstable"))] extern crate test;
+#![cfg_attr(all(test, feature = "_bench_unstable"), feature(test))]
+#[cfg(all(test, feature = "_bench_unstable"))] extern crate test;
 
 mod util;
 
@@ -362,7 +362,7 @@ mod tests {
 	}
 }
 
-#[cfg(all(test, feature = "unstable"))]
+#[cfg(all(test, feature = "_bench_unstable"))]
 pub mod bench {
 	use test::Bencher;
 

lightning/Cargo.toml

@@ -24,7 +24,7 @@ max_level_trace = []
 # Allow signing of local transactions that may have been revoked or will be revoked, for functional testing (e.g. justice tx handling).
 # This is unsafe to use in production because it may result in the counterparty publishing taking our funds.
 unsafe_revoked_tx_signing = []
-unstable = []
+_bench_unstable = []
 
 no-std = ["hashbrown", "bitcoin/no-std", "core2/alloc"]
 std = ["bitcoin/std"]

lightning/src/lib.rs

@@ -30,8 +30,8 @@
 
 #![cfg_attr(all(not(feature = "std"), not(test)), no_std)]
 
-#![cfg_attr(all(any(test, feature = "_test_utils"), feature = "unstable"), feature(test))]
-#[cfg(all(any(test, feature = "_test_utils"), feature = "unstable"))] extern crate test;
+#![cfg_attr(all(any(test, feature = "_test_utils"), feature = "_bench_unstable"), feature(test))]
+#[cfg(all(any(test, feature = "_test_utils"), feature = "_bench_unstable"))] extern crate test;
 
 #[cfg(not(any(feature = "std", feature = "no-std")))]
 compile_error!("at least one of the `std` or `no-std` features must be enabled");

lightning/src/ln/channelmanager.rs

@@ -7132,7 +7132,7 @@ mod tests {
 	}
 }
 
-#[cfg(all(any(test, feature = "_test_utils"), feature = "unstable"))]
+#[cfg(all(any(test, feature = "_test_utils"), feature = "_bench_unstable"))]
 pub mod bench {
 	use chain::Listen;
 	use chain::chainmonitor::{ChainMonitor, Persist};

lightning/src/ln/functional_test_utils.rs

@@ -1137,7 +1137,7 @@ macro_rules! expect_pending_htlcs_forwardable_from_events {
 	}}
 }
 
-#[cfg(any(test, feature = "unstable"))]
+#[cfg(any(test, feature = "_bench_unstable"))]
 macro_rules! expect_payment_received {
 	($node: expr, $expected_payment_hash: expr, $expected_payment_secret: expr, $expected_recv_value: expr) => {
 		let events = $node.node.get_and_clear_pending_events();

lightning/src/routing/network_graph.rs

@@ -2687,7 +2687,7 @@ mod tests {
 	}
 }
 
-#[cfg(all(test, feature = "unstable"))]
+#[cfg(all(test, feature = "_bench_unstable"))]
 mod benches {
 	use super::*;
 

lightning/src/routing/router.rs

@@ -455,7 +455,7 @@ struct PathBuildingHop<'a> {
 	/// decrease as well. Thus, we have to explicitly track which nodes have been processed and
 	/// avoid processing them again.
 	was_processed: bool,
-	#[cfg(any(test, feature = "fuzztarget"))]
+	#[cfg(all(not(feature = "_bench_unstable"), any(test, feature = "fuzztarget")))]
 	// In tests, we apply further sanity checks on cases where we skip nodes we already processed
 	// to ensure it is specifically in cases where the fee has gone down because of a decrease in
 	// value_contribution_msat, which requires tracking it here. See comments below where it is
@@ -896,14 +896,14 @@ where L::Target: Logger {
 								path_htlc_minimum_msat,
 								path_penalty_msat: u64::max_value(),
 								was_processed: false,
-								#[cfg(any(test, feature = "fuzztarget"))]
+								#[cfg(all(not(feature = "_bench_unstable"), any(test, feature = "fuzztarget")))]
 								value_contribution_msat,
 							}
 						});
 
 						#[allow(unused_mut)] // We only use the mut in cfg(test)
 						let mut should_process = !old_entry.was_processed;
-						#[cfg(any(test, feature = "fuzztarget"))]
+						#[cfg(all(not(feature = "_bench_unstable"), any(test, feature = "fuzztarget")))]
 						{
 							// In test/fuzzing builds, we do extra checks to make sure the skipping
 							// of already-seen nodes only happens in cases we expect (see below).
@@ -992,13 +992,13 @@ where L::Target: Logger {
 								old_entry.fee_msat = 0; // This value will be later filled with hop_use_fee_msat of the following channel
 								old_entry.path_htlc_minimum_msat = path_htlc_minimum_msat;
 								old_entry.path_penalty_msat = path_penalty_msat;
-								#[cfg(any(test, feature = "fuzztarget"))]
+								#[cfg(all(not(feature = "_bench_unstable"), any(test, feature = "fuzztarget")))]
 								{
 									old_entry.value_contribution_msat = value_contribution_msat;
 								}
 								did_add_update_path_to_src_node = true;
 							} else if old_entry.was_processed && new_cost < old_cost {
-								#[cfg(any(test, feature = "fuzztarget"))]
+								#[cfg(all(not(feature = "_bench_unstable"), any(test, feature = "fuzztarget")))]
 								{
 									// If we're skipping processing a node which was previously
 									// processed even though we found another path to it with a
@@ -4976,7 +4976,7 @@ pub(crate) mod test_utils {
 	}
 }
 
-#[cfg(all(test, feature = "unstable", not(feature = "no-std")))]
+#[cfg(all(test, feature = "_bench_unstable", not(feature = "no-std")))]
 mod benches {
 	use super::*;
 	use bitcoin::hashes::Hash;