Telegram DM topic bindings persist (chat_id, thread_id) -> session_id in
SQLite so reopening a topic resumes the right Hermes session. When
compression rotated session_entry.session_id mid-turn, the binding row
stayed pointed at the pre-compression parent. On the next inbound
message in that topic the gateway reloaded the oversized parent
transcript, retriggering preflight compression — sometimes in a loop.
Two-pronged fix:
1. `_sync_telegram_topic_binding(source, entry, *, reason)` helper
called immediately after each of the three session_id rotation sites
in _handle_message_with_agent (hygiene compression, agent-result
compression rotation, /compress command). Keeps future bindings
fresh.
2. Read-path self-heal: when resolving an existing topic binding, walk
SessionDB.get_compression_tip() forward and switch_session to the
descendant instead of the stored parent. Rewrites the binding row to
the tip so subsequent messages skip the walk. Heals existing stale
state on the next user message without requiring a gateway restart.
Skipped from competing PRs as not load-bearing for the bug:
- advance_session_after_compression SessionStore primitive (#26204/
#28870/#33416) — preserves end_reason='compression' analytics nicety
but doesn't affect routing correctness.
- Cached-agent eviction on session_id mismatch — _compress_context()
already mutates tmp_agent.session_id on the cached object so the
in-memory agent self-corrects.
- Startup repair pass (#33416) — redundant once the read path heals on
the next message; one-line CLI follow-up can address bindings for
topics users never reopen.
Closes#20470, #29712, #33414. Acknowledges work in #23195
(@litvinovvo), #26204 (@bizyumov), #28870 (@donrhmexe), #29713
(@hehehe0803), #29945 (@eugeneb1ack), #33416 (@bizyumov).
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