[secsovereign]

Summary

Follow-up to PR #22 (testnet4 support, merged as badc23e). Fixes how BLVM decides which network's Bitcoin Core block files to read when it reuses a Core datadir in place (storage.reuse_core_block_files, on by default).

On main, a Core datadir whose network could not be detected silently became mainnet, so a custom signet (signet_<hash>) or an unrecognised folder could get a reader with the wrong network magic. This PR stops that without dropping reuse for real mainnet datadirs with non-standard names.

Network rule for Core block reuse

BitcoinCoreDetection::resolve_reuse_network(core_dir, marker_network, node_network) decides the network from three sources, in this order:

1. the network in the BLVM migration marker (blvm_meta/migration.json); empty counts as absent
2. the Core datadir folder name (.bitcoin/bitcoind → mainnet, testnet3, testnet4, signet, regtest)
3. the network the node is running (open_for_node passes it; library callers pass consensus_network)

Every source that is known must agree, and the first known one wins. Reuse is skipped with a warning, and no reader is opened, when:

• the folder is a custom signet (signet_<hash>), whatever the marker or node say, because its block magic is not the standard signet magic
• two known sources disagree (e.g. a mainnet marker on .bitcoin/signet, or a mainnet node on .bitcoin/testnet3)
• the marker names a network BLVM doesn't know
• no source is known

So ~/Library/Application Support/Bitcoin, %APPDATA%\Bitcoin, bitcoin or /srv/btc-data opened by a mainnet node keep block reuse, and nothing falls back to mainnet by default.

Changes

src/storage/bitcoin_detection.rs

• detect_network: custom signet (signet_<hash>) and unknown folders return None instead of mainnet.
• detect_network_strict (new): an error for custom signets and unknown folders. The custom signet message names the setting that actually applies (storage.reuse_core_block_files = false), not a --network flag.
• resolve_reuse_network (new): the rule above.
• is_bitcoin_core_dir: now public, and checks the network's subfolder (testnet3/, testnet4/, signet/, regtest/; mainnet at the root).

src/storage/mod.rs

• open_core_block_reader_for_store takes the node network and uses resolve_reuse_network. The marker's network is no longer trusted unchecked.
• open_blockstore and both storage constructors pass the caller's consensus_network through. with_backend_pruning_and_indexing no longer swaps an unknown network for Some(Mainnet) before Core reuse.

Small accessors

• BitcoinCoreBlockReader::network() and BlockStore::bitcoin_core_reader_network() (rocksdb), used by the tests.

CI

• New Run tests (rocksdb feature) step: cargo test --features rocksdb. The rocksdb-gated Core import and reuse code was never compiled into a test run before. That's how the E0624 in the previous head went unnoticed.

Tests

• src/storage/core_reuse_tests.rs (new, #[cfg(all(test, feature = "rocksdb"))]): calls open_core_block_reader_for_store from inside the crate. It replaces the integration test that called this pub(crate) fn and failed to compile with E0624. It covers:
  • non-standard mainnet names (bitcoin, Bitcoin, srv/btc-data) with a mainnet node → mainnet reader
  • the same name with no marker and no node network → no reader
  • a mainnet marker on .bitcoin/signet → no reader
  • a signet marker on signet_<hash> → no reader (with and without a signet node)
  • marker vs folder, marker vs node, and folder vs node disagreements → no reader
  • agreeing sources → reader on that network
  • end to end through Storage::with_backend_pruning_and_indexing
• bitcoin_detection unit tests for resolve_reuse_network: priority, every disagreement pair, custom signet with every marker/node combination, an unknown marker network, and the wording of the custom signet message. These run with default features too.

Results:

Run locally at b79ba28 (crates.io deps as in CI: [patch.crates-io] stripped, blvm-protocol 0.1.30, blvm-consensus 0.1.54; -j 2):

	default features	--features rocksdb
--lib	1329 passed, 2 ignored	1346 passed, 2 ignored
--test bitcoin_core_tests	1 passed	21 passed
--test storage_tests	36 passed	36 passed
--test core_drop_in_integration	(rocksdb only)	8 passed
cargo clippy -- -D warnings	--lib --bins --examples clean	--lib clean

cargo fmt --check is clean. One default-features --lib run failed node::parallel_ibd::tip_stage::tests::tip_crawl_supply_healthy_requires_past_body_and_fast_gd_or_stream, which is timing-sensitive and not touched here. It passed 3/3 in isolation and in the full rerun. The other ~195 integration test binaries were not run locally because of disk on the shared box. CI's Run tests and the new Run tests (rocksdb feature) step cover them.

Revert checks (each fix reverted alone, cargo test --features rocksdb):

• B2, node network not passed to the reader: 5 tests fail (nonstandard_mainnet_names_reuse_with_node_network_mainnet, nonstandard_name_follows_node_network, open_for_node_passes_the_node_network_to_core_reuse, folder_and_node_disagreement_is_refused, marker_and_node_disagreement_is_refused)
• S3, marker trusted unchecked: 5 tests fail (mainnet_marker_on_standard_signet_folder_is_refused, marker_and_folder_disagreement_is_refused, marker_and_node_disagreement_is_refused, resolve_marker_folder_disagreement_refuses, resolve_node_disagreement_refuses)
• custom signet guard removed from the resolver: 4 tests fail (custom_signet_core_dir_does_not_produce_a_reader, signet_marker_on_custom_signet_folder_is_refused, resolve_custom_signet_refuses_whatever_the_other_sources_say, custom_signet_error_names_the_real_setting)
• old --network wording: custom_signet_error_names_the_real_setting fails
• B1, the old integration test put back: --test bitcoin_core_tests fails to compile (E0624, private fn)

Out of scope

• The consensus_network.unwrap_or(Mainnet) defaults still used for pruning in with_backend_pruning_and_indexing / with_backend_pruning_indexing_and_compression are unchanged. Core block reuse no longer depends on them.
• When reuse is refused, the node keeps running without the Core reader and logs a warning. It does not fail startup.