ENGINEERING CASE STUDY
Receipt continuity under partial writes, concurrency and corruption.
Blackbox receipt persistence is designed to preserve truthful chain state when writes are interrupted, multiple writers contend for the next chain position, or malformed data appears at the storage boundary.
Engineering problem
An append-only evidence ledger becomes unreliable if a torn write, duplicate chain-head allocation or malformed complete row can be silently normalized into apparently valid history.
Implementation
The current V2 receipt store serializes append, allocates the chain head under lock, uses durable flush behavior, detects torn tails and refuses to silently mix legacy and V2 rows.
Negative controls
Current tests exercise torn-tail repair before the next append, refusal to truncate a complete malformed row, explicit migration requirements for legacy logs and concurrent append serialization.
Boundary
These controls establish the tested receipt-storage behavior. Customer deployment, filesystem-specific durability, certification and enterprise custody readiness remain separately evidenced states.