RFC 0053 split — history and file map

RFC 0053 originally specified WAL backpressure, publish-time unwind safety, publication frontiers and tenant settlement, and an RFC 0005 §3.7 audit-durability amendment together, in one 3172-line document (rfc/0053-wal-backpressure-unwind @ 30a21f80). It was split into four RFCs so each could reach its own maturity gate independently; this page records what moved where. That original draft is the source of the reviewed prose each of the three new RFCs (0054–0056) extracts into its own §9 (cited there as “the quarry”); RFC 0053 itself ends at §8.

Resulting files

File	Owns	Source in the original draft
`docs/rfcs/0053-wal-backpressure.md`	Bound, reservation, wire contract, latch, forced-rotation livelock, `max_segments` as a header cap, backpressure telemetry.	§1 first half, §2.1, §3.1 minus seal/owed-rotation essay, §3.3 backpressure rows, RFC0053.1 / .4 / .5, §6 backpressure legs
`docs/rfcs/0054-publish-unwind-safety.md`	Invariant: no acknowledged batch becomes unreachable on panic; duplicates over loss; sweep may continue.	§2.2, §3.2 ownership / drain / worker / publisher panic, RFC0053.2 / .3
`docs/rfcs/0055-publication-frontiers.md`	`PUBLISHED` sidecar, per-tenant record+audit watermarks, settlement rebuild, tenant slots, object-key intent, sidecar geometry.	The rest of §3.2, restart/sidecar legs of RFC0053.4
`docs/rfcs/0056-audit-durability.md`	Amends RFC 0005 §3.7: permanent audit failure is not a successful drop; dependent records stay unpublished; tenant becomes terminal.	Status-note amendment + the three-way `write_owned` result

What moved to RFC 0052 instead

Some material in the original draft was a request of RFC 0052 rather than specification belonging to 0053, and landed there (on #798) instead of being kept here:

Journal::framed_len, rotation_due, RotationDecision token on append_batch
Journal::rotate result / RotationKind (discretionary vs owed)
.wal.seal and the torn-tail heal
rebuild_ledger() / remeasure_unreclaimed() as the restart seed
HousekeepingProgress.removed_segments, reclaimable_now, ReclaimSchedule
cadence_failed retirement, failure_generation

What RFC 0053 kept and what it dropped

RFC 0053 itself kept: pre-append reservation; frame-byte unreclaimed total; checked add; TooLarge first; 503/UNAVAILABLE + protobuf Status + Retry-After hint; per-request admission vs refusal latch; forced rotation predicate; unreclaimed_bytes_limit / max_segments; RFC0053.1, .4 (WAL restart figure only), .5; §4 sink-ceiling as a validated prerequisite.

It dropped, to the three new RFCs: RecoverableBatch / pool supervisor; PUBLISHED and settlement; the RFC 0005 / 0046 / 0048 amendments; max_tenants slot reservation (now RFC 0055). .wal.seal is not among these — it is requested of RFC 0052, per the section above.

Review discipline applied during the split

The split preserved the original draft’s already-reviewed wording by cutting and moving paragraphs rather than rewriting them from memory, and a Copilot review was deferred until all four files existed and RFC 0053 itself was under 800 lines — so review comments would land on the settled shape rather than on an intermediate one. Every new file started at status drafted; RFC 0053 itself dropped from specified back to drafted until its §3 held only backpressure.

Result

Four markdown files exist, indexed in docs/SUMMARY.md, and RFC 0053 is at drafted. The split was announced on #802, which lists what moved where.