Module error 

BlockStore error surface (BlockStoreError).

Requirements

• ERR-001 — thirteen variants, thiserror::Error + Debug.
• ERR-002 — From<rocksdb::Error> (via #[from]), From<bincode::Error> for Serialization, and explicit zstd / std::io::Error → Compression mapping (BlockStoreError::compression_from_io).
• ERR-003 — every variant’s std::fmt::Display (via thiserror #[error]) must embed actionable context: hashes as hex (Bytes32 implements Display), numeric fields inlined, and static messages for unit variants (NORMATIVE ERR-003).
• Normative: ERR domain NORMATIVE.
• SPEC: SPEC.md §12 (error taxonomy; ERR-001 adds EmptyReorgChain and PipelineClosed beyond the SPEC snippet).

Operational errors without a first-class variant

ERR-001 caps the enum at thirteen cases. Some STR-004 guards (missing read-only path, read-only mutation, double genesis) therefore map to BlockStoreError::Serialization with stable string payloads documented below so integration tests and future refactors can match deterministically. If the taxonomy gains dedicated variants later, these constants become the migration anchor.

Enums

BlockStoreError

Crate-level error for persistence, chain, and I/O boundaries (ERR-001).

Constants

ERR_ASYNC_JOIN_PREFIX

Stable BlockStoreError::Serialization payload prefix when a tokio::task::spawn_blocking task panics or is cancelled and tokio::task::JoinError surfaces on .await (BLK-007 AC §6).

ERR_INIT_GENESIS_ALREADY_INITIALIZED

Stable BlockStoreError::Serialization payload when genesis metadata is already present.

ERR_INIT_GENESIS_READ_ONLY

Stable BlockStoreError::Serialization payload when crate::store::BlockStore::init_genesis runs on a read-only handle.

ERR_MUTATION_READ_ONLY

Stable BlockStoreError::Serialization payload for other mutating APIs (crate::store::BlockStore::put) on a read-only handle (BLK-001 precursor).

ERR_OPEN_READONLY_PATH_MISSING_PREFIX

Stable BlockStoreError::Serialization payload prefix when crate::store::BlockStore::open_readonly is called with a path that does not exist on disk.

ERR_UPDATE_STATUS_RECORD_NOT_CACHED_PREFIX

Stable BlockStoreError::Serialization payload prefix when crate::store::BlockStore::update_status runs but the in-memory record cache has no entry for the hash (BLK-010 AC §3).