Flush messages before compression/session rotation

Fixes on record

Merged to main. A stamp counts the issues a fix is linked to.

• #48584 fix(compression): preserve messages across session rotation (flush-before-rotate + /compress rewrite guard)

  merged to main

  files: agent/conversation_compression.py, cli.py, gateway/slash_commands.py

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  • agent/conversation_compression.py

    @@ -512,6 +512,16 @@ def _release_lock() -> None:
                 old_title = agent._session_db.get_session_title(agent.session_id)
                 # Trigger memory extraction on the old session before it rotates.
                 agent.commit_memory_session(messages)
    +            # Flush any un-persisted messages from the current turn to the
    +            # old session *before* rotating.  compress_context() can be
    +            # called mid-turn (auto-compress when context exceeds threshold)
    +            # at a point when _flush_messages_to_session_db() has not yet
    +            # run.  Without this, messages generated during the current turn
    +            # are silently lost on session rotation (#47202).
    +            try:
    +                agent._flush_messages_to_session_db(messages)
    +            except Exception:
    +                pass  # best-effort — don't block compression on a flush error
                 agent._session_db.end_session(agent.session_id, "compression")
                 old_session_id = agent.session_id
                 agent.session_id = f"{datetime.now().strftime('%Y%m%d_%H%M%S')}_{uuid.uuid4().hex[:6]}"

  • cli.py

    @@ -5957,6 +5957,18 @@ def new_session(self, silent=False, title=None):
     
             old_session_id = self.session_id
             if self._session_db and old_session_id:
    +            # Flush any un-persisted messages from the current turn to the
    +            # old session *before* rotating.  /new can be called mid-turn
    +            # when _flush_messages_to_session_db() has not yet run — without
    +            # this, messages generated during the current turn are silently
    +            # lost on session rotation (#47202).
    +            if self.agent:
    +                try:
    +                    self.agent._flush_messages_to_session_db(
    +                        self.conversation_history
    +                    )
    +                except Exception:
    +                    pass  # best-effort
                 try:
                     self._session_db.end_session(old_session_id, "new_session")
                 except Exception:

  • gateway/slash_commands.py

    @@ -2588,14 +2588,29 @@ async def _handle_compress_command(self, event: MessageEvent) -> str:
                     # session_id for the continuation.  Write the compressed messages
                     # into the NEW session so the original history stays searchable.
                     new_session_id = tmp_agent.session_id
    -                if new_session_id != session_entry.session_id:
    +                rotated = new_session_id != session_entry.session_id
    +                if rotated:
                         session_entry.session_id = new_session_id
                         self.session_store._save()
                         self._sync_telegram_topic_binding(
                             source, session_entry, reason="compress-command",
                         )
     
    -                self.session_store.rewrite_transcript(new_session_id, compressed)
    +                # Only rewrite the transcript when rotation actually produced a
    +                # NEW session id. If _compress_context could not rotate (e.g.
    +                # _session_db unavailable, or the DB split raised), session_id
    +                # is unchanged and rewrite_transcript() would DELETE the
    +                # original messages and replace them with only the compressed
    +                # summary — permanent data loss (#44794, #39704). In that case
    +                # leave the original transcript intact.
    +                if rotated:
    +                    self.session_store.rewrite_transcript(new_session_id, compressed)
    +                else:
    +                    logger.warning(
    +                        "Manual /compress: session rotation did not occur "
    +                        "(session_id unchanged) — preserving original transcript "
    +                        "instead of overwriting it (#44794)."
    +                    )
                     # Reset stored token count — transcript changed, old value is stale
                     self.session_store.update_session(
                         session_entry.session_key, last_prompt_tokens=0