Re-derivation of #23254 (@devsart95) on today's flush loop. The turn
flush in _flush_messages_to_session_db wrote one BEGIN IMMEDIATE
transaction per message row; a typical agent turn (user + assistant +
tool results) paid 3-8 transactions -- and, off WAL (the default on
macOS while the WAL-reset guard is active), 3-8 fsyncs -- per turn.
Adds SessionDB.append_messages_batch: same row shape as append_message
(shared _prepare_message_row serializer + _MESSAGE_INSERT_SQL column
list, so the two writers cannot drift), same compression-lock and
compression-closed guards, one aggregated session-counter UPDATE, one
transaction for the whole batch. Row serialization stays outside the
write lock.
The flush loop now collects the turn's new rows and writes them in one
call. All-or-nothing pairs exactly with the persisted-marker stamping:
on failure no rows landed and no markers were stamped, so the next
flush re-writes the whole tail (same recovery contract as before,
minus the partial-prefix case that could double-count).
Measured (same harness, 5-message turn, journal_mode=DELETE,
synchronous=FULL): 2.32ms -> 0.83ms median per turn flush (64% faster,
5 fsyncs -> 1). On WAL the win is smaller but the atomicity fix holds.
Ephemeral empty-response/prefill recovery scaffolding (the synthetic
assistant "(empty)" turn, the user nudge, the terminal "(empty)"
sentinel, and the thinking-only prefill placeholder) exists only to
drive the next API retry; the in-memory loop pops it before appending
the real response. The append-only flush did not mirror that, so a
mid-turn persist could commit scaffolding to the SQLite session store
(and JSON log), and a resumed session would replay synthetic
"(empty)"/nudge turns as genuine context — re-poisoning the empty-retry
boundary forever.
Filter ephemeral scaffolding at both durable-write sites
(_flush_messages_to_session_db + _save_session_log), by flag not
position, so buried scaffolding (an answered nudge leaves the synthetic
pair mid-list) is skipped too. Covers all three flags including
_thinking_prefill.
Adapted onto current main's identity-tracking flush.
Cherry-picked from #41281 by petrichor-op.
state.db now stores every message field the JSON snapshot stored. Removed
the method, all 7 call-sites, and ~13 test stubs that suppressed its file I/O.
Body is in git history if it ever needs to come back.
When empty-response terminal scaffolding fires on a tool-result turn,
_drop_trailing_empty_response_scaffolding left the live history ending at
a bare 'tool' message. The next user input then landed as [...tool, user],
a protocol-invalid sequence that OpenRouter/Opus and other providers
silently fail on (returns empty content). That retriggered the empty-retry
recovery every turn, and recovery flags never hit SQLite (no column for
them), so history kept looking broken on every reload.
Two fixes:
1. Scaffolding strip rewinds the orphan assistant(tool_calls)+tool pair
after popping sentinels. Only fires when scaffolding flags were
actually present, so mid-iteration tool loops are untouched.
2. _repair_message_sequence runs right before every API call as a
defensive belt: drops stray tool messages with unknown tool_call_ids,
merges consecutive user messages so no user input is lost. Does NOT
rewind assistant(tool_calls)+tool+user — that pattern is valid when
the user redirected before the model got its continuation turn.
Repro: session 20260507_044111_fa7e65. Opus-4.7/OpenRouter returned
content-less response after a 42KB execute_code output, nudge+retry
chain exhausted (no fallback configured), terminal sentinel appended,
scaffolding stripped leaving bare tool tail, user typed 'wtf happened..'
and landed as tool→user violation. Every subsequent turn collapsed in
<50ms with the same 3-retry empty chain because the API request itself
was malformed.
Verified live via HTTP mock: pre-fix reproduced 5 api_calls/0.15s exit
'empty_response_exhausted'; post-fix 1 api_call/0.10s exit
'text_response(finish_reason=stop)'. Three-turn session flows cleanly
through the scenario. Full run_agent suite: 1242 passed (0 regressions,
2 pre-existing concurrent_interrupt failures unrelated).
devsart95
Teknium
petrichor-op
yoniebans
wxst