Task 5a of docs/superpowers/plans/2026-08-26-table-residency.md. The read
path itself is NOT in this commit; see the note below.
- the offset problem is far smaller than the spec feared. `w->off` is the
durable tail and `w->len` the staged bytes, and wo_wal_commit pwrites the
whole batch AT off before advancing it — so a record staged now lands at
exactly off+len, knowable at append time with no deferral to flush
- shipped as an inline accessor rather than new out-params on the three
append functions, so the 156 existing WAL checks keep their signatures
- correct across both awkward cases, and both are now unit-pinned:
a failed commit leaves off unadvanced so the record still lands where it
was promised, and wo_wal_open positions off at the end of the INTACT
prefix so offsets are always relative to validated data
- test_offset_capture asserts the recovered ID per record, not merely that a
record parses — a wrong offset reads a NEIGHBOURING record, which passes
its own CRC and returns the wrong row silently. 400 records across
repeated buffer growth (stage() doubles from 4096) and uneven commit
batches, so offsets are exercised mid-buffer and right after a flush
The failed-commit test caught MY OWN misunderstanding: I asserted
next_offset was unchanged after a failed commit. It is not, and should not
be — the record is still staged, so next_offset correctly points PAST it.
The invariant that matters is that the durable tail did not move, which is
what it now asserts.
Gates: test_wal 3428/0 (was 3426), all 18 runtime suites 0 fail under
ASan+UBSan, cli_smoke OK, oop-e2e 119/0, residency 8/0.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
shoney.arickathil
3290c7d117