Phase 4 commit #1 per docs/PHASE4.md §12. Two file changes bundled
because R-B1 (flock for race-free single-writer enforcement) cannot
be deferred — adding it retroactively means reopening the memory
handle.
ffi/libc.lua extensions:
- cdef flock(int fd, int op), open(...), lseek(int, long, int)
- constants LOCK_EX=2, LOCK_NB=4, LOCK_UN=8
- M.flock(fd, op) wrapper returning (true) on success or
(false, errmsg) — errmsg is the strerror text so callers can
surface "Resource temporarily unavailable" cleanly to the user.
history.lua additions (Phase 4 section appended at end):
- M.open_memory(path) -> handle | nil, err
Opens the file via libc.open(2) (need integer fd for flock —
io.open's FILE* doesn't expose it), takes flock(LOCK_EX | LOCK_NB).
Returns "memory.jsonl held by another aish process" on lock-held.
Scans existing content for max id; caches as handle.next_id.
Writes meta header on first creation (no id, ignored at load).
- handle:add(kind, content, tags?, source?) -> id
Assigns next id; appends one JSONL item with auto-timestamp.
kind ∈ {fact, pref, context} enforced via assert.
- handle:forget(target_id)
Appends a tombstone {id, ts, kind:"forget", target}.
- handle:close()
Releases fd (flock auto-released on close).
- M.load_memory(path) -> items_table
Reads all lines, builds forget-target set from kind=="forget"
entries, returns active items as an array sorted by ts desc.
Items without id (meta header) silently dropped. Tombstones with
non-matching targets are no-ops (N3 invariant).
Round-trip test passes:
- open empty file → next_id=1
- add 3 items → ids 1, 2, 3
- forget id 2 (appends tombstone)
- reopen → next_id correctly advances past the tombstone (=5)
- load_memory → 2 active items (id 1 + id 3); tombstone resolved
- lock-held detection: second open while first held → fails with
"memory.jsonl held by another aish process" message
- close releases the lock; reopen after release succeeds
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
marfrit
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