Module blockchain 

Blockchain collection kind — pure logic.

A KIND blockchain collection stores append-only rows whose hash field depends on the previous row’s hash, forming a tamper-evident chain. Issue #521 lands the engine integration in a later iteration; this module ships the deterministic primitives (hash, verify_chain, error types) so the later wiring is a thin storage adapter on top of audited logic.

Structs

Block

A materialized block as stored. hash MUST equal compute_block_hash(...) over the other fields — verify_chain enforces this.

ChainTip

Engine response to GET /collections/:name/chain-tip.

SignedFields

Optional signer fields included in the hash preimage when the collection has SIGNED_BY (...) declared. Issue #520 supplies the signer registry; the chain hash binds the signature so a replaced signature also breaks the chain.

Enums

BlockchainError

Operational errors surfaced by the blockchain engine path.

VerifyReport

Result of walking a chain end-to-end. Inconsistent reports the FIRST block whose stored fields disagree with a recomputed hash; the chain is not walked past the first failure.

Constants

GENESIS_PREV_HASH

All-zero hash used as prev_hash for the genesis block.

Functions

compute_block_hash

Canonical hash preimage:

verify_chain

Walk blocks in order. Returns the first inconsistency or Ok if every block’s stored hash matches the recomputed hash AND links the previous block.