Sibling site of the same loss class. The #72680 shutdown flush only
serialised the adapter slot (_pending_messages); the FIFO tail parked in
SessionState.conversation.queued_events was discarded with the process,
so every follow-up queued behind the head at restart time vanished the
same way the idle-orphan did. flush_overflow_to_file writes one payload
per overflow event in the slot-flush shape (plus seq for arrival order),
so the existing recover_pending_to_db startup replay inserts them with no
new reader. Wired into _stop_impl beside the slot flush.
A gateway process opened state.db from ~12 call sites, each minting its
own writer connection, self._lock, close-time WAL checkpoint, and
token-writer thread. With N independent writers on one WAL file, one
connection's close-time checkpoint could race another's growth — the
lost/reordered-page-write signature across 11+ incidents (#90837).
Adds hermes_state_registry.py: a process-wide, per-path, refcounted
shared registry owning the writer boundary.
- acquire(path): same resolved path returns the same instance (one
writer connection, one lock, one token-writer thread) for every
long-lived in-process caller (gateway runner, SessionStore, per-agent
lazy recall, cron per-job, mirror, channel_directory, slash_commands,
shutdown_flush, session_search, react_to_message, delegate, mcp_serve,
auto_archive, tui_gateway).
- close() on a shared instance is a NO-OP — the registry owns the
lifecycle, so one caller's close can never tear down a writer other
callers still hold.
- Generation-aware retirement on inode change: a replaced state.db
RETIRES the live generation (never lent again) but keeps it alive for
existing holders; release is object-keyed so holders of the old
generation drain it independently of the new one. The old
generation's own write path still fails with the typed
StateDbReplacedError (existing protection, unchanged).
- Replacement-open failure leaves NO registry entry for the path —
the next acquire retries fresh, never hands out a closed stale object.
- All teardown runs OUTSIDE the registry lock: a final release's WAL
checkpoint can never stall acquisition for every state.db.
- close_shared_session_dbs() at gateway shutdown drains every
generation (live + retired) as the final safety net.
CLI one-shots, recovery flows, and read-only cross-profile opens keep
using SessionDB() directly with their own close() — only long-lived
in-process sites route through the registry.
References #90837 (root-cause tracker stays open: the #10 EOF signature
and the WAL-lifecycle A/B verdict remain under investigation there).
SessionDB could leave native SQLite handles open when construction failed
partway through schema/pragma/FTS/repair/lock/interrupt handling. Other
short-lived callers (MCP reads/polling, session search, reactions, trace
upload, insights, shutdown recovery) opened temporary SessionDB handles
without a complete ownership boundary. API-server profile caches and
RetainDB shutdown had similar late-close races. Under sustained load this
exhausted file descriptors (EMFILE).
- Close partially initialized SessionDB connections on every constructor
exception path via a finally block guarded by an initialization-complete
flag.
- Close temporary/cross-profile SessionDB handles in finally blocks across
CLI, MCP, search, trace, reactions, insights, and recovery paths.
- Add API-server per-profile cache ownership and disconnect cleanup.
- Make RetainDB writer-queue shutdown exception-safe: track connections per
thread, close on worker exit, reject new enqueues after shutdown starts,
and sweep any connections left by short-lived threads.
- Add regression coverage for constructor failures, worker-thread readers,
API disconnect failures, shutdown recovery, RetainDB late enqueue, and
foreign-loop async clients.
Salvage notes: the original PR's per-thread WAL-reader ownership changes
were superseded by main's read-connection pool (permits + checkout/return);
its cron timeout-abandon fix is credited separately to #72822's earlier
identical fix.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
When the per-session pending transcript queue hits _MAX_PENDING_PER_SESSION
(200) while the session DB is broken, the gateway previously popped the
oldest message and discarded it permanently — silent user data loss during
live operation (#78182). The on-disk pending spool only ran at shutdown via
flush_pending_to_file.
Extend that existing spool machinery for runtime drops:
- gateway/shutdown_flush.py: add spool_dropped_transcript_message() and
drain_transcript_spool(), reusing _get_flush_dir/_write_payload (same
atomic-JSON pending_messages/ spool format). recover_pending_to_db()
now also replays transcript_cap_drop payloads left over across restarts.
- gateway/session.py: on cap eviction, spool the dropped message and log a
WARNING that includes the spool path; if spooling fails, degrade to the
previous drop-and-warn behavior. On the next fully successful transcript
flush for that session, drain and replay spooled messages in drop order;
replay failures keep the spool files for the next attempt.
- tests/gateway/test_pending_queue_spool.py: drop→spool→drain roundtrip,
per-session drain isolation, spool-failure degradation, replay-failure
retention, and spool primitive ordering/reason filtering.
No new config; extends existing flush_pending_to_file infrastructure per
AGENTS.md guidance.
Refs #82616, #78182
Follow-up for salvaged PRs #73400 + #73372:
- Move _preserve_agent_history_on_shutdown logic into
gateway/shutdown_flush.py as flush_agent_history_to_file()
- Reuse the hardened _write_payload (atomic writes, fsync, private
permissions, UUID filenames) from #73372 instead of the plain
open()/write() from #73400
- Replace os.environ.get('HERMES_HOME') with get_hermes_home() for
profile-safe path resolution
- Update tests to test the real function directly
- Net: removes 37 lines from gateway/run.py, unifies both fix paths
in a single module with consistent atomic-write guarantees
Replace 20 lines of manual os.open/O_EXCL/fdopen/fsync/os.replace with the
existing atomic_json_write() from utils.py, which is already used by 6+
modules and handles temp-file creation, fsync, atomic replace, mode
control, and owner preservation. The only novel helper (_fsync_directory)
is retained — atomic_json_write does not do directory fsync.
Update test_flush_write_failure_leaves_no_recovery_file to monkeypatch
utils.os.replace (the new call path) instead of gateway.shutdown_flush.os.replace.
Critical fixes to salvaged PR #73020:
- Use SessionDB.append_message instead of raw INSERT INTO messages.
The original used wrong column names (session_key/created_at vs
session_id/timestamp) and bypassed FTS indexing, session metadata
updates, display_kind, and all other columns append_message handles.
- Use get_hermes_home() instead of hardcoded Path.home()/'.hermes'.
Profile-aware path resolution under HERMES_HOME override and active
profile isolation.
- Add 11 tests covering flush, recovery, serialisation, edge cases.
When FTS5 index corruption prevents INSERT INTO messages, the gateway
accumulates messages in _pending_messages (memory-only). On shutdown,
.clear() discards the only surviving copy — permanent user data loss.
Changes:
- Add gateway/shutdown_flush.py with flush_pending_to_file() and
recover_pending_to_db() for two-phase data preservation.
- Patch gateway/run.py: flush runner._pending_messages before clear()
in _stop_impl_body, and recover on startup after runner.start().
- Patch gateway/platforms/base.py: flush adapter._pending_messages
before clear() in the adapter shutdown path.
Recovery behavior:
- Reads pending JSON files from ~/.hermes/pending_messages/
- Inserts messages into state.db directly
- Per-session isolation: one corrupt session doesn't block others
- Successful recovery deletes the flush file
- Failed recovery re-saves for next startup retry
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