fix: harden assistant SQLite/PostgreSQL dual-backend (singleton, timeouts, warnings)

Co-authored-by: Cursor <cursoragent@cursor.com>

svc/persistence/assistant_store.py

@@ -2,13 +2,20 @@
 
 from __future__ import annotations
 
+import hashlib
+import threading
 from pathlib import Path
 
-from svc.config.database import assistant_db_backend, assistant_postgres_dsn
+from svc.config.database import (
+    assistant_db_backend,
+    assistant_postgres_dsn,
+    assistant_sqlalchemy_url,
+)
 from svc.persistence.assistant_store_protocol import AssistantStoreProtocol
 
 _singleton: AssistantStoreProtocol | None = None
 _singleton_key: str | None = None
+_lock = threading.Lock()
 
 
 def reset_assistant_store_singleton() -> None:
@@ -29,6 +36,12 @@ def get_assistant_store() -> AssistantStoreProtocol:
     does not re-run PostgreSQL bootstrap / orphan pruning on every HTTP or WS call (which could race
     with in-flight writes and make messages disappear after tool rounds).
 
+    The cache key for PostgreSQL uses a **hash of the SQLAlchemy URL** (not the raw DSN string) so logs
+    and debug dumps are less likely to embed credentials.
+
+    When the effective key changes (e.g. tests switch ``AIA_ASSISTANT_DB_PATH`` or DSN), the SQLAlchemy
+    engine cache is cleared so pooled connections are not reused for the wrong database.
+
     Tests should keep constructing ``SqliteStore(path)`` with an explicit file path; production code
     should prefer this factory for ``db_path()``-backed instances.
 
@@ -40,18 +53,27 @@ def get_assistant_store() -> AssistantStoreProtocol:
     from svc.persistence.sqlite_store import SqliteStore
 
     if assistant_db_backend() == "postgresql":
-        key = f"postgresql::{assistant_postgres_dsn()}"
+        key = f"postgresql::{hashlib.sha256(assistant_sqlalchemy_url().encode()).hexdigest()}"
     else:
         key = f"sqlite::{Path(db_path()).resolve()}"
 
-    if _singleton is not None and _singleton_key == key:
+    inst = _singleton
+    if inst is not None and _singleton_key == key:
+        return inst
+
+    with _lock:
+        if _singleton is not None and _singleton_key == key:
+            return _singleton
+        if _singleton_key is not None and _singleton_key != key:
+            from svc.persistence.db.engine import clear_assistant_engine_cache
+
+            clear_assistant_engine_cache()
+        if assistant_db_backend() == "postgresql":
+            _singleton = SqliteStore(None, postgres_url=assistant_postgres_dsn())
+        else:
+            _singleton = SqliteStore(db_path())
+        _singleton_key = key
         return _singleton
-    if assistant_db_backend() == "postgresql":
-        _singleton = SqliteStore(None, postgres_url=assistant_postgres_dsn())
-    else:
-        _singleton = SqliteStore(db_path())
-    _singleton_key = key
-    return _singleton
 
 
 __all__ = ["get_assistant_store", "reset_assistant_store_singleton"]