Block-sync-only all-target check imports disabled transaction_sync module #168

Summary

The documented block-sync-only feature set builds the application binary, but cargo check --all-targets fails because an Esplora test module imports transaction_sync while that module is disabled.

Affected revision

• Branch: dev
• Commit: af03c7f1a65135a429f05a5820600338215954dc
• Package version: 0.1.0

Reproduction

cargo +1.94.0 check --locked --all-targets \
  --no-default-features \
  --features "block-sync,electrum,esplora"

Actual result

The command exits with status 101:

error[E0432]: unresolved import `crate::ldk_chain_backend::transaction_sync`
 --> src/test/esplora_indexer_defaults.rs:8:31

src/test/esplora_indexer_defaults.rs enables the import and its three interpolation tests with only #[cfg(feature = "esplora")], while src/ldk_chain_backend/mod.rs exposes transaction_sync only under #[cfg(feature = "transaction-sync")].

Expected result

All targets should compile for the documented block-sync-only combination. Tests that exercise transaction-sync helpers should be excluded when transaction-sync is disabled.

Scope and user impact

This is a developer/CI feature-matrix failure, not a binary installation failure. The README's corresponding command succeeds:

cargo install --locked --path . --no-default-features \
  --features block-sync,electrum,esplora

The resulting rgb-lightning-node 0.1.0 binary was produced successfully. The defect prevents checking or testing all targets for that supported feature set.

Relevant source

• Failing import and tests:

  rgb-lightning-node/src/test/esplora_indexer_defaults.rs

  Lines 7 to 10 in af03c7f

  	#[cfg(feature = "esplora")]
  	use crate::ldk_chain_backend::transaction_sync::{
  	estimate_fee_rate_sat_per_kw, interpolate_fee_rate,
  	};

• Module feature gate:

  rgb-lightning-node/src/ldk_chain_backend/mod.rs

  Lines 3 to 4 in af03c7f

  	#[cfg(feature = "transaction-sync")]
  	pub(crate) mod transaction_sync;

• Documented feature set:

  rgb-lightning-node/README.md

  Lines 70 to 79 in af03c7f

  	### Chain sync support
  	Support for the chain sync backends is behind cargo features, `block-sync` and
  	`transaction-sync` (both enabled by default). At least one of them needs to be
  	enabled. See [Sync modes](#sync-modes) for what each backend does.
  	To support the block-sync backend only:
  	```sh
  	cargo install --locked --path . --no-default-features --features block-sync,electrum,esplora
  	```

Duplicate-check evidence

Open and closed issues and PRs in both UTEXO and upstream were searched for esplora_indexer_defaults, block-sync, transaction_sync, --all-targets, and the E0432 text. Issue comments, review comments, and current overlapping PRs were also inspected. PRs #139 and #140 touch the failing test and introduce the currently mismatched gates, but neither contains a fix or discusses this feature-matrix failure. No duplicate or active fix was found. Private maintainer discussions are not visible.

Suggested fix direction

Require both features for the transaction-sync-only imports and interpolation tests, for example #[cfg(all(feature = "esplora", feature = "transaction-sync"))], while leaving default_fee_buckets_populates_all_targets available to block-sync builds. Add this block-sync-only --all-targets combination to the compile matrix.