fix: DbSessionAdapter.clear_session must purge persisted messages (#1737)

clear_session only cleared the in-memory cache while BotSessionManager
and managed agents rewrite history via clear_session + add_message.
Stale DB rows were reloaded on the next on_agent_start, resurrecting
trimmed or cleared chat history.

- Call conversation.delete_messages when available
- Reset session tracking and skip stale on_agent_start hydration
- Add regression test for bot history trim roundtrip

Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: Mervin Praison <MervinPraison@users.noreply.github.com>

Author: 3 people

src/praisonai-agents/tests/managed/test_managed_persistence.py

@@ -349,6 +349,50 @@ def test_metadata_roundtrip(self):
         assert meta["agent_id"] == "abc"
         assert meta["total_input_tokens"] == 42
 
+    def test_clear_session_purges_db_history(self):
+        """clear_session must not leave stale messages reloadable from the DB."""
+        from praisonai.integrations.db_session_adapter import DbSessionAdapter
+        from praisonaiagents.db.protocol import DbMessage
+
+        persisted: list = []
+
+        mock_db = MagicMock()
+
+        def _on_start(agent_name, session_id):
+            return list(persisted)
+
+        def _on_user(sid, content, **kw):
+            persisted.append(DbMessage(role="user", content=content))
+
+        def _on_assistant(sid, content, **kw):
+            persisted.append(DbMessage(role="assistant", content=content))
+
+        mock_db.on_agent_start.side_effect = _on_start
+        mock_db.on_user_message.side_effect = _on_user
+        mock_db.on_agent_message.side_effect = _on_assistant
+
+        conv = MagicMock()
+        conv.delete_messages.side_effect = lambda sid, ids: persisted.clear()
+        mock_db.conversation = conv
+
+        adapter = DbSessionAdapter(mock_db)
+        sid = "bot-trim-session"
+        adapter.add_message(sid, "user", "old")
+        adapter.add_message(sid, "assistant", "old-reply")
+        assert len(persisted) == 2
+
+        adapter.clear_session(sid)
+        conv.delete_messages.assert_called_once_with(sid, None)
+        assert persisted == []
+        assert adapter.get_chat_history(sid) == []
+
+        adapter.add_message(sid, "user", "new-only")
+        assert len(adapter.get_chat_history(sid)) == 1
+        assert len(persisted) == 1
+
+        adapter2 = DbSessionAdapter(mock_db)
+        assert adapter2.get_chat_history(sid) == [{"role": "user", "content": "new-only"}]
+
 
 # ===========================================================================
 # 7. ManagedAgent factory wiring

src/praisonai/praisonai/integrations/db_session_adapter.py

@@ -37,16 +37,43 @@ def __init__(self, db: Any):
         self._sessions: Set[str] = set()
         self._metadata: Dict[str, Dict[str, Any]] = {}
         self._history_cache: Dict[str, List[Dict[str, str]]] = {}
+        self._cleared_sessions: Set[str] = set()
+
+    def _conversation_store(self) -> Any:
+        """Optional ConversationStore behind the DbAdapter (if present)."""
+        conv = getattr(self._db, "conversation", None)
+        if conv is not None:
+            return conv
+        orchestrator = getattr(self._db, "_orchestrator", None)
+        return getattr(orchestrator, "conversation", None) if orchestrator else None
+
+    def _purge_persisted_messages(self, session_id: str) -> None:
+        """Remove persisted messages when the session is cleared or deleted."""
+        conv = self._conversation_store()
+        if conv is not None and hasattr(conv, "delete_messages"):
+            try:
+                conv.delete_messages(session_id, None)
+            except Exception as e:
+                logger.warning(
+                    "[db_session_adapter] delete_messages failed for %s: %s",
+                    session_id,
+                    e,
+                )
 
     def _ensure_session(self, session_id: str, agent_name: str = "ManagedAgent") -> None:
         """Ensure session exists in the DB adapter."""
         if session_id not in self._sessions:
+            skip_history = session_id in self._cleared_sessions
+            if skip_history:
+                self._cleared_sessions.discard(session_id)
             try:
                 msgs = self._db.on_agent_start(agent_name, session_id)
-                if msgs:
+                if msgs and not skip_history:
                     self._history_cache[session_id] = [
                         {"role": m.role, "content": m.content} for m in msgs
                     ]
+                elif skip_history:
+                    self._history_cache[session_id] = []
                 self._sessions.add(session_id)
             except Exception as e:
                 logger.warning("[db_session_adapter] on_agent_start failed: %s", e)
@@ -99,14 +126,24 @@ def get_chat_history(
 
     def clear_session(self, session_id: str) -> bool:
         """Clear all messages from a session."""
-        self._history_cache.pop(session_id, None)
+        if session_id in self._sessions:
+            try:
+                self._db.on_agent_end(session_id)
+            except Exception as e:
+                logger.warning("[db_session_adapter] on_agent_end failed: %s", e)
+        self._purge_persisted_messages(session_id)
+        self._history_cache[session_id] = []
+        self._sessions.discard(session_id)
+        self._cleared_sessions.add(session_id)
         return True
 
     def delete_session(self, session_id: str) -> bool:
         """Delete a session completely."""
+        self._purge_persisted_messages(session_id)
         self._history_cache.pop(session_id, None)
         self._metadata.pop(session_id, None)
         self._sessions.discard(session_id)
+        self._cleared_sessions.discard(session_id)
         try:
             self._db.on_agent_end(session_id)
         except Exception: