deriveOwed decides "is this ask still owed?" by asking whether one of my own
terminal replies is LATER than the ask. It compared `seq` — this database's
arrival rowid. On a single hub that is global order, so it was correct; the
comment above it already said hlc was the durable key "once mesh_peers reports
actual peers". Making the switch now, while one replica means the two orderings
agree, costs nothing; making it later means changing the rule while two machines
already disagree about order.
The bug being pre-empted is specific: with a second replica the same event gets
a different `seq` in each database, because arrival order is not authorship
order. A reply authored after its ask can arrive first and take the lower seq;
the join then concludes "no later reply exists" and an already-answered ask
reappears as owed — permanently, on that machine.
isStrictlyAfter() prefers `hlc` when both events carry one and falls back to
`seq` otherwise (a server predating the field, or an un-backfilled row). hlc is
rendered fixed-width, <unix_ms:13 digits>-<counter:6 hex>-<replica_id>, so a
plain string comparison IS the causal comparison, with the replica id as final
tiebreak. Verified before writing the code that the field is actually on the
wire — event_list returns it per event (logstream.py:593) — because a fallback
that never fires would have made this a no-op dressed as a fix.
`created_at` stays rejected, and the reason is now written down where the
decision is: it is server-generated at second precision, so ties are routine,
and a tie can suppress an UNANSWERED ask. Both remaining failure modes are on
the noisy-but-visible side — an answered item resurfacing is annoying, an
unanswered ask going silent defeats the mailbox.
Tested: 18 cases against the extracted comparator — hlc later/earlier/equal,
same-ms counter ties in hex (0x10 vs 0x9, which is where a non-padded format
would break), cross-replica tiebreak, both mesh reorderings, every seq-fallback
path, and degenerate input (null seq, numeric hlc, empty strings, no keys) which
must never claim "answered". All pass. Real-data check on the positive-control
pair: seq 26/27 carry hlc ...3071857/...3574085, so the orderings agree today
and the switch is a no-op now and correct later.
The cursor keeps the opposite ordering ON PURPOSE — since_event_id is
local-arrival ordered so a tail consumer still sees late-arriving remote ops
whose hlc is older (hlc.py:19-21). RFC 003 §9.3 now says so explicitly, because
that asymmetry looks like a bug worth "fixing" and is not.
joakimp
bfe9c5cd4f