Introduce Rust features by tnull · Pull Request #1061 · lightningdevkit/ldk-node

tnull · 2026-08-19T12:35:57Z

Closes #900

Previously, we omitted making use of Rust features to dis-/enable specific functionality, with the exception of uniffi and most recently adding a tentative postgres feature.

Here we finally change that and allow users to selectively disable and enable specific parts of the code base, hence also reducing their dependency tree.

Allow integration runs to constrain randomized chain sources through the LDK_NODE_TEST_CHAIN_SOURCES environment variable. This makes backend-specific feature builds deterministic while preserving all-backend randomization by default. Co-Authored-By: HAL 9000

Keep filesystem-specific code together so generic storage utilities can compile without that backend. This commit only relocates the existing migration behavior and tests. Co-Authored-By: HAL 9000

Hide the concrete Bitcoin Core gossip verifier behind the LDK UTXO lookup trait. This lets common gossip types compile independently of the Bitcoin Core backend without changing verification behavior. Co-Authored-By: HAL 9000

Keep human-readable-name resolution beside the unified payment code that consumes it. This commit only relocates the existing resolver and updates its internal import paths. Co-Authored-By: HAL 9000

Define the cfg-selected Builder name next to the implementation it represents. Feature-specific binding exports can now live there without changing the native and lock-wrapped builder APIs. Co-Authored-By: HAL 9000

ldk-reviews-bot · 2026-08-19T12:36:00Z

👋 Thanks for assigning @benthecarman as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

Keep the native defaults while letting applications select only required chain sources, storage backends, and unified payment support. At least one chain source remains mandatory. PostgreSQL now has a storage-prefixed feature name. Co-Authored-By: HAL 9000

Separate backend-specific binding methods into cfg-gated implementation blocks. Method bodies and availability remain unchanged, making later conditional exports easier to review. Co-Authored-By: HAL 9000

Keep binding signatures and documentation next to their Rust implementations. Leave only the UDL object declaration so backend features can add methods without failure stubs. Co-Authored-By: HAL 9000

Build published bindings with uniffi-default and without native default features. Let local builds add backend features through LDK_NODE_EXTRA_FEATURES. Co-Authored-By: HAL 9000

Build and test UniFFI with its lean preset so excluded backends stay excluded. Check all features and test targets to catch incompatible optional dependencies without running the suite twice. Co-Authored-By: HAL 9000

List each chain, storage, payment, and binding feature and explain the unchanged native defaults. Show both lean and custom binding builds so optional backend dependencies can be selected deliberately. Co-Authored-By: HAL 9000

benthecarman

Would be good to have CI cover the missed feature configs that claude caught

benthecarman · 2026-08-19T22:53:52Z

+	feature = "chain-electrum",
+	feature = "chain-bitcoind"
+)))]
+compile_error!("at least one chain source feature must be enabled");


should do same with db

benthecarman · 2026-08-20T00:46:18Z

@@ -47,47 +47,6 @@ interface ProbingConfigBuilder {
 };



bindings/ldk_node.udl:73 — unified_payment() is declared unconditionally in the UDL while the Rust side is gated on unified-payments, so the same combo also fails with E0425. Effectively uniffi requires storage-vss + unified-payments, but nothing enforces or documents that.

benthecarman · 2026-08-20T00:46:53Z

+use crate::config::{BackgroundSyncConfig, Config, WALLET_SYNC_INTERVAL_MINIMUM_SECS};
 use crate::fee_estimator::OnchainFeeEstimator;
 use crate::logger::{log_debug, log_error, log_info, log_trace, LdkLogger, Logger};
 use crate::runtime::Runtime;


the vss_client import isn’t gated on storage-vss, so any uniffi build without it fails (E0433). The README’s own example command cargo build --no-default-features --features uniffi,chain-bitcoind,storage-postgres doesn’t compile.

benthecarman · 2026-08-20T00:47:41Z

@@ -213,6 +213,7 @@ impl Wallet {
 		self.inner.lock().expect("lock").tx_graph().full_txs().map(|tx_node| tx_node.tx).collect()
 	}


src/wallet/mod.rs:2813 — the in-crate wallet unit tests call ChainSource::new_esplora ungated, so cargo test breaks on any set without chain-esplora.

benthecarman · 2026-08-20T00:48:00Z

@@ -362,25 +362,52 @@ pub(crate) fn setup_bitcoind_and_electrsd() -> (BitcoinD, ElectrsD) {
 pub(crate) fn random_chain_source<'a>(


tests/common/mod.rs:45 — the integration-test harness imports SqliteStore unconditionally, so postgres-only test runs break.

benthecarman · 2026-08-20T00:49:13Z

+	fs::create_dir_all(parent_dir).map_err(|_| BuildError::StoragePathAccessFailed)?;
+	recover_incomplete_fs_store_migration(&storage_dir_path)?;
+	if !storage_dir_path.exists() {
+		fs::create_dir_all(storage_dir_path.clone())


uneeded clone

benthecarman · 2026-08-20T00:49:32Z

+			let v1_store = FilesystemStore::new(storage_dir_path.clone());
+
+			let v2_dir = fs_store_sibling_path(&storage_dir_path, "fs_store_v2_migrating");
+			fs::create_dir_all(v2_dir.clone()).map_err(|_| BuildError::StoragePathAccessFailed)?;


unneeded clone

tnull added 5 commits August 19, 2026 14:32

Move filesystem migration to its own module

94579e9

Keep filesystem-specific code together so generic storage utilities can compile without that backend. This commit only relocates the existing migration behavior and tests. Co-Authored-By: HAL 9000

Decouple gossip from Bitcoin Core types

2e5d577

Hide the concrete Bitcoin Core gossip verifier behind the LDK UTXO lookup trait. This lets common gossip types compile independently of the Bitcoin Core backend without changing verification behavior. Co-Authored-By: HAL 9000

Move HRN resolution into payment module

d96ffc2

Keep human-readable-name resolution beside the unified payment code that consumes it. This commit only relocates the existing resolver and updates its internal import paths. Co-Authored-By: HAL 9000

Keep builder aliases beside their types

8220338

Define the cfg-selected Builder name next to the implementation it represents. Feature-specific binding exports can now live there without changing the native and lock-wrapped builder APIs. Co-Authored-By: HAL 9000

tnull added this to the 0.8 milestone Aug 19, 2026

tnull requested a review from benthecarman August 19, 2026 12:35

tnull added 6 commits August 19, 2026 15:38

Group binding builder methods by feature

1e7bbfc

Separate backend-specific binding methods into cfg-gated implementation blocks. Method bodies and availability remain unchanged, making later conditional exports easier to review. Co-Authored-By: HAL 9000

Define binding builder methods in Rust

f1c604a

Keep binding signatures and documentation next to their Rust implementations. Leave only the UDL object declaration so backend features can add methods without failure stubs. Co-Authored-By: HAL 9000

Use lean defaults for binding builds

16eb063

Build published bindings with uniffi-default and without native default features. Let local builds add backend features through LDK_NODE_EXTRA_FEATURES. Co-Authored-By: HAL 9000

Check lean and complete feature sets in CI

54e8c15

Build and test UniFFI with its lean preset so excluded backends stay excluded. Check all features and test targets to catch incompatible optional dependencies without running the suite twice. Co-Authored-By: HAL 9000

Document selectable crate features

7f339e5

List each chain, storage, payment, and binding feature and explain the unchanged native defaults. Show both lean and custom binding builds so optional backend dependencies can be selected deliberately. Co-Authored-By: HAL 9000

tnull force-pushed the 2026-08-rust-features branch from 9b4022f to 7f339e5 Compare August 19, 2026 13:40

benthecarman reviewed Aug 20, 2026

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Introduce Rust features - #1061

Introduce Rust features#1061
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		@@ -213,6 +213,7 @@ impl Wallet {
		self.inner.lock().expect("lock").tx_graph().full_txs().map(\|tx_node\| tx_node.tx).collect()
		}

		@@ -362,25 +362,52 @@ pub(crate) fn setup_bitcoind_and_electrsd() -> (BitcoinD, ElectrsD) {
		pub(crate) fn random_chain_source<'a>(

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