The cutover: new tail segments write format v2 (per-record [type, version,
cipherFlag, keyId] envelope; noun/verb after-images carry dense ints
MINTED AT APPEND from the id mapper — a rebuilt mapper reproduces
assignments exactly; log.genesis opens every new log with the id-space
width + a minted brain id; sync() seals to the header-declared sector
boundary with reader-invisible pad frames). Existing v1 segments are
never rewritten — per-segment decoder dispatch reads both formats and v2
facts map to the exact CommitFact shape all consumers already read.
Cutover on a live v1 log: an empty v1 tail re-heads in place; a non-empty
one is sealed by rotation, byte-identical. Records reserve the encryption
fields (cipherFlag 0 / keyId nil are the only legal values; anything else
refuses typed naming the needed newer reader) — crypto-ready with no
future bump on the compat surface. Empty-records facts are legal (an
all-deduped batch is a real generation — v1 semantics preserved; the
refusal there tore a column-store flush mid-commit in the full suite, the
consistency guard caught it loudly, and the root is fixed).
Golden byte vectors pinned for the second (native) reader implementation.
Pins: cutover 5/5 · codec 54 · kill-matrix stays 11/11.
Two release-blocking findings from the durability kill-matrix, both fixed
in the owning layer:
1. LOG-AUTHORITY REPLAY AT OPEN: durable-at-ack fsynced the fact before
the ack, but open() truncated every fact above the manifest — after a
power loss that takes the un-fsynced tmp+rename canonical bytes, the
acked write's ONLY durable copy was discarded. Now: under 'log'
authority, open() REPLAYS intact facts above the manifest into
canonical (FactLog.peekFactsAbove — CRC-gated, order-sorted) and
advances the manifest to cover them; tree-authority brains keep the
truncate contract they were promised. Pinned end to end: the power-loss
row constructs the exact disk state (fsynced log, vanished canonical
rename) and the acked write lives.
2. NO SILENT COMMIT: commitSingleOp buffered the generation BEFORE the
fact append; an append failure (ENOSPC) rejected the caller but the
next flush durably committed the generation with NO fact — a permanent
silent log gap. Now the failure path un-buffers and returns the counter
reservation: nothing commits, the log stays gap-free, and the canonical
execute-residue orphan is the documented crash-equivalent.
Plus: the kill-matrix itself (11 rows — every commit-path fault point ×
reopen-as-crash recovery contract, at-ack variants, disk-full row; five
new zero-cost faultPoint sites), the log-authority pin suite (oracle
green/red/state-differs, flip refusal, switch survives reopen, 9/9), and
the group-commit covering pins (5/5).
Gates: unit 2002/2002 (152 files) · integration 785 · conformance 27/27.
