The anti-thrash guard (_ineffective_compression_count) was in-memory
only: a fresh compressor bound to a resumed, already-compacted session
started with compression_count=0 and a disarmed guard, so a
near-threshold session could legally re-compact once per process
restart, forever.
Persist the counter through the durable session-state channel,
mirroring the failure-cooldown (#54465) and fallback-streak (af7dceaf7)
pattern:
- hermes_state.py: sessions.compression_ineffective_count column
(declarative reconciliation adds it on existing DBs) +
get/set_compression_ineffective_count accessors.
- context_compressor.py: every strike/clear verdict routes through
_record_ineffective_compression_verdict() which writes through to the
session row (no-change verdicts skip the DB write);
bind_session_state() loads the persisted value; the compression
rotation boundary carries the counter onto the child row;
update_model()'s reset also clears the durable copy; the
ineffective-only fast path in _automatic_compression_blocked() is
removed because the counter is now durable and another agent's clear
must unblock a stale local snapshot.
- conversation_compression.py: _refresh_persisted_compression_guards
re-reads the counter alongside cooldown + fallback streak.
Reset semantics are unchanged: any real provider reading below the
threshold still clears the counter — and now clears it durably too.
Resolves the residual gap identified in #54923 by @lanyusea (the
second-threshold mechanism was superseded by persisting the existing
guard state).
Co-authored-by: lanyusea <lanyusea@gmail.com>
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