Bump MSRV to rustc 1.75.0

We generally align our MSRV with Debian's stable channel. Debian 13
'Trixie' was just released, shipping rustc 1.85. However, as 1.85.0 is
only about ~7months old at this point, we opt to bump to the more
conservative 1.75.0, which approaches two years of age.

Author: tnull

.github/workflows/build.yml

@@ -31,10 +31,10 @@ jobs:
       fail-fast: false
       matrix:
         platform: [ self-hosted, windows-latest, macos-latest ]
-        toolchain: [ stable, beta, 1.63.0 ] # 1.63.0 is the MSRV for all crates but `lightning-transaction-sync`.
+        toolchain: [ stable, beta, 1.75.0 ] # 1.75.0 is the MSRV for all crates
         exclude:
           - platform: windows-latest
-            toolchain: 1.63.0
+            toolchain: 1.75.0
           - platform: windows-latest
             toolchain: beta
           - platform: macos-latest
@@ -60,7 +60,7 @@ jobs:
           shellcheck ci/*.sh -aP ci
           shellcheck contrib/*.sh -aP contrib
       - name: Set RUSTFLAGS to deny warnings
-        if: "matrix.toolchain == '1.63.0'"
+        if: "matrix.toolchain == '1.75.0'"
         run: echo "RUSTFLAGS=-D warnings" >> "$GITHUB_ENV"
       - name: Run CI script
         shell: bash # Default on Winblows is powershell
@@ -71,7 +71,7 @@ jobs:
       fail-fast: false
       matrix:
         platform: [ ubuntu-latest, macos-latest ]
-        toolchain: [ stable, beta, 1.75.0 ] # 1.75.0 is the MSRV for `lightning-transaction-sync`.
+        toolchain: [ stable, beta, 1.75.0 ]
     runs-on: ${{ matrix.platform }}
     steps:
       - name: Checkout source code
@@ -254,17 +254,13 @@ jobs:
   fuzz:
     runs-on: self-hosted
     env:
-      TOOLCHAIN: 1.63
+      TOOLCHAIN: 1.75
     steps:
       - name: Checkout source code
         uses: actions/checkout@v4
       - name: Install Rust ${{ env.TOOLCHAIN }} toolchain
         run: |
           curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --profile=minimal --default-toolchain ${{ env.TOOLCHAIN }}
-      - name: Pin the regex dependency
-        run: |
-          cd fuzz && cargo update -p regex --precise "1.9.6" --verbose
-          cd write-seeds && cargo update -p regex --precise "1.9.6" --verbose
       - name: Sanity check fuzz targets on Rust ${{ env.TOOLCHAIN }}
         run: |
           cd fuzz
@@ -293,7 +289,7 @@ jobs:
   rustfmt:
     runs-on: ubuntu-latest
     env:
-      TOOLCHAIN: 1.63.0
+      TOOLCHAIN: 1.75.0
     steps:
       - name: Checkout source code
         uses: actions/checkout@v4

CONTRIBUTING.md

@@ -88,7 +88,7 @@ be covered by functional tests.
 When refactoring, structure your PR to make it easy to review and don't
 hesitate to split it into multiple small, focused PRs.
 
-The Minimum Supported Rust Version (MSRV) currently is 1.63.0 (enforced by
+The Minimum Supported Rust Version (MSRV) currently is 1.75.0 (enforced by
 our GitHub Actions). We support reading serialized LDK objects written by any
 version of LDK 0.0.99 and above. We support LDK versions 0.0.113 and above
 reading serialized LDK objects written by modern LDK. Any expected issues with
@@ -124,7 +124,7 @@ display fine at any tab-length display setting. We use `rustfmt` to establish
 uniform coding standards throughout the codebase. Please run
 
 ```bash
-cargo +1.63.0 fmt
+cargo +1.75.0 fmt
 ```
 
 before committing and pushing any changes, as compliance will also be checked

ci/check-lint.sh

@@ -47,7 +47,6 @@ CLIPPY() {
 		-A clippy::len_without_is_empty \
 		-A clippy::len_zero \
 		-A clippy::let_and_return \
-		-A clippy::manual_div_ceil `# to be removed once we hit MSRV 1.73.0` \
 		-A clippy::manual_filter \
 		-A clippy::manual_map \
 		-A clippy::manual_memcpy \
@@ -106,9 +105,7 @@ CLIPPY() {
 		-A clippy::unnecessary_unwrap \
 		-A clippy::unused_unit \
 		-A clippy::useless_conversion \
-		-A clippy::unnecessary_map_or `# to be removed once we hit MSRV 1.70` \
 		-A clippy::manual_repeat_n `# to be removed once we hit MSRV 1.86` \
-		-A clippy::io_other_error `# to be removed once we hit MSRV 1.74` \
 		-A clippy::manual_is_multiple_of `# to be removed once we hit MSRV 1.87` \
 		-A clippy::uninlined-format-args
 }

ci/ci-tests.sh

@@ -2,40 +2,20 @@
 #shellcheck disable=SC2002,SC2207
 set -eox pipefail
 
-RUSTC_MINOR_VERSION=$(rustc --version | awk '{ split($2,a,"."); print a[2] }')
+# Currently unused as we don't have to pin anything for MSRV:
+#RUSTC_MINOR_VERSION=$(rustc --version | awk '{ split($2,a,"."); print a[2] }')
 
 # Some crates require pinning to meet our MSRV even for our downstream users,
 # which we do here.
 # Further crates which appear only as dev-dependencies are pinned further down.
 function PIN_RELEASE_DEPS {
-	# Starting with version 1.39.0, the `tokio` crate has an MSRV of rustc 1.70.0
-	[ "$RUSTC_MINOR_VERSION" -lt 70 ] && cargo update -p tokio --precise "1.38.1" --verbose
-
 	return 0 # Don't fail the script if our rustc is higher than the last check
 }
 
 PIN_RELEASE_DEPS # pin the release dependencies in our main workspace
 
-# Starting with version 1.10.0, the `regex` crate has an MSRV of rustc 1.65.0.
-[ "$RUSTC_MINOR_VERSION" -lt 65 ] && cargo update -p regex --precise "1.9.6" --verbose
-
-# The addr2line v0.21 crate (a dependency of `backtrace` starting with 0.3.69) relies on rustc 1.65
-[ "$RUSTC_MINOR_VERSION" -lt 65 ] && cargo update -p backtrace --precise "0.3.68" --verbose
-
-# The once_cell v1.21.0 crate (a dependency of `proptest`) relies on rustc 1.70
-[ "$RUSTC_MINOR_VERSION" -lt 70 ] && cargo update -p once_cell --precise "1.20.3" --verbose
-
-# proptest 1.3.0 requires rustc 1.64.0
-[ "$RUSTC_MINOR_VERSION" -lt 64 ] && cargo update -p proptest --precise "1.2.0" --verbose
-
-# parking_lot 0.12.4 requires rustc 1.64.0
-[ "$RUSTC_MINOR_VERSION" -lt 64 ] && cargo update -p parking_lot --precise "0.12.3" --verbose
-
-# parking_lot_core 0.9.11 requires rustc 1.64.0
-[ "$RUSTC_MINOR_VERSION" -lt 64 ] && cargo update -p parking_lot_core --precise "0.9.10" --verbose
-
-# lock_api 0.4.13 requires rustc 1.64.0
-[ "$RUSTC_MINOR_VERSION" -lt 64 ] && cargo update -p lock_api --precise "0.4.12" --verbose
+# The backtrace v0.3.75 crate relies on rustc 1.82
+[ "$RUSTC_MINOR_VERSION" -lt 82 ] && cargo update -p backtrace --precise "0.3.74" --verbose
 
 export RUST_BACKTRACE=1
 
@@ -49,7 +29,6 @@ cargo test --verbose --color always
 
 echo -e "\n\nTesting upgrade from prior versions of LDK"
 pushd lightning-tests
-[ "$RUSTC_MINOR_VERSION" -lt 65 ] && cargo update -p regex --precise "1.9.6" --verbose
 cargo test
 popd
 

lightning-invoice/src/de.rs

@@ -102,7 +102,7 @@ impl FromBase32 for Bolt11InvoiceFeatures {
 		// Carry bits, 0, 1, 2, 3, or 4 bits
 		let mut carry_bits = 0;
 		let mut carry = 0u8;
-		let expected_raw_length = (field_data.len() * 5 + 7) / 8;
+		let expected_raw_length = (field_data.len() * 5).div_ceil(8);
 		let mut output = Vec::<u8>::with_capacity(expected_raw_length);
 
 		// Iterate over input in reverse

lightning-invoice/src/ser.rs

@@ -237,7 +237,7 @@ fn encode_int_be_base32(int: u64) -> impl ExactSizeIterator<Item = Fe32> {
 /// The length of the output of `encode_int_be_base32`.
 fn encoded_int_be_base32_size(int: u64) -> usize {
 	let bit_len = 64 - int.leading_zeros() as usize; // cast ok as value is in 0..=64.
-	(bit_len + 4) / 5
+	bit_len.div_ceil(5)
 }
 
 impl Base32Iterable for RawDataPart {

lightning-liquidity/src/lsps2/service.rs

@@ -781,7 +781,7 @@ where
 	/// Returns whether the peer has any active LSPS2 requests.
 	pub(crate) fn has_active_requests(&self, counterparty_node_id: &PublicKey) -> bool {
 		let outer_state_lock = self.per_peer_state.read().unwrap();
-		outer_state_lock.get(counterparty_node_id).map_or(false, |inner| {
+		outer_state_lock.get(counterparty_node_id).is_some_and(|inner| {
 			let peer_state = inner.lock().unwrap();
 			!peer_state.outbound_channels_by_intercept_scid.is_empty()
 		})

lightning-liquidity/src/lsps5/service.rs

@@ -596,7 +596,7 @@ where
 		// (other than lsps5.webhook_registered) close in time.
 		if notification.method != WebhookNotificationMethod::LSPS5WebhookRegistered {
 			let rate_limit_applies = peer_state.webhooks().iter().any(|(_, webhook)| {
-				webhook.last_notification_sent.as_ref().map_or(false, |last_sent| {
+				webhook.last_notification_sent.as_ref().is_some_and(|last_sent| {
 					now.duration_since(&last_sent) < NOTIFICATION_COOLDOWN_TIME
 				})
 			});

lightning-liquidity/src/manager.rs

@@ -770,12 +770,12 @@ where
 								let lsps2_has_active_requests = self
 									.lsps2_service_handler
 									.as_ref()
-									.map_or(false, |h| h.has_active_requests(sender_node_id));
+									.is_some_and(|h| h.has_active_requests(sender_node_id));
 								#[cfg(lsps1_service)]
 								let lsps1_has_active_requests = self
 									.lsps1_service_handler
 									.as_ref()
-									.map_or(false, |h| h.has_active_requests(sender_node_id));
+									.is_some_and(|h| h.has_active_requests(sender_node_id));
 								#[cfg(not(lsps1_service))]
 								let lsps1_has_active_requests = false;
 
@@ -918,7 +918,7 @@ where
 	fn provided_node_features(&self) -> NodeFeatures {
 		let mut features = NodeFeatures::empty();
 
-		let advertise_service = self.service_config.as_ref().map_or(false, |c| c.advertise_service);
+		let advertise_service = self.service_config.as_ref().is_some_and(|c| c.advertise_service);
 
 		if advertise_service {
 			features
@@ -932,7 +932,7 @@ where
 	fn provided_init_features(&self, _their_node_id: PublicKey) -> InitFeatures {
 		let mut features = InitFeatures::empty();
 
-		let advertise_service = self.service_config.as_ref().map_or(false, |c| c.advertise_service);
+		let advertise_service = self.service_config.as_ref().is_some_and(|c| c.advertise_service);
 		if advertise_service {
 			features
 				.set_optional_custom_bit(LSPS_FEATURE_BIT)

lightning-persister/src/utils.rs

@@ -26,7 +26,7 @@ pub(crate) fn check_namespace_key_validity(
 				PrintableString(secondary_namespace),
 				PrintableString(key)
 			);
-			return Err(std::io::Error::new(std::io::ErrorKind::Other, msg));
+			return Err(std::io::Error::other(msg));
 		}
 
 		if primary_namespace.is_empty() && !secondary_namespace.is_empty() {
@@ -37,7 +37,7 @@ pub(crate) fn check_namespace_key_validity(
 			let msg = format!(
 				"Failed to {} {}/{}/{}: primary namespace may not be empty if a non-empty secondary namespace is given.", operation,
 				PrintableString(primary_namespace), PrintableString(secondary_namespace), PrintableString(key));
-			return Err(std::io::Error::new(std::io::ErrorKind::Other, msg));
+			return Err(std::io::Error::other(msg));
 		}
 
 		if !is_valid_kvstore_str(primary_namespace)
@@ -50,7 +50,7 @@ pub(crate) fn check_namespace_key_validity(
 			let msg = format!("Failed to {} {}/{}/{}: primary namespace, secondary namespace, and key must be valid.",
 				operation,
 				PrintableString(primary_namespace), PrintableString(secondary_namespace), PrintableString(key));
-			return Err(std::io::Error::new(std::io::ErrorKind::Other, msg));
+			return Err(std::io::Error::other(msg));
 		}
 	} else {
 		if primary_namespace.is_empty() && !secondary_namespace.is_empty() {
@@ -60,7 +60,7 @@ pub(crate) fn check_namespace_key_validity(
 			let msg = format!(
 				"Failed to {} {}/{}: primary namespace may not be empty if a non-empty secondary namespace is given.",
 				operation, PrintableString(primary_namespace), PrintableString(secondary_namespace));
-			return Err(std::io::Error::new(std::io::ErrorKind::Other, msg));
+			return Err(std::io::Error::other(msg));
 		}
 		if !is_valid_kvstore_str(primary_namespace) || !is_valid_kvstore_str(secondary_namespace) {
 			debug_assert!(
@@ -76,7 +76,7 @@ pub(crate) fn check_namespace_key_validity(
 				PrintableString(primary_namespace),
 				PrintableString(secondary_namespace)
 			);
-			return Err(std::io::Error::new(std::io::ErrorKind::Other, msg));
+			return Err(std::io::Error::other(msg));
 		}
 	}