A user prompt that exists only in Hermes state.db (no sidecar copy) and falls
chronologically BEFORE a newer sidecar message tail was being appended after the
tail (or skipped) by merge_session_messages_append_only — losing or mis-ordering
it on load. The merge now inserts such a state.db user message at its correct
chronological position via _insert_state_message_chronologically, with a
role-aware tie-break for equal timestamps. Append-only invariant + dedup
(seen_content_keys) preserved.
Deterministic-ordering guard (maintainer add, addresses Codex review): on an
equal-timestamp collision the insert no longer lands at a slot whose left
neighbour shares the message's role — it advances past the same-role
equal-timestamp run, so an already-answered earlier turn can't be re-ordered
into user,user,assistant. (The agent core merges adjacent users before send, so
this was benign in practice, but the guard keeps the merged transcript correctly
ordered regardless.) +1 same-second multi-turn regression test, toothless-checked.
Co-authored-by: Dennis Soong <dso2ng@gmail.com>
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