Merge pull request #887 from MemPalace/fix/kg-close-lock

fix: add lock to KG close() — last missing lock (closes #883)

mempalace/knowledge_graph.py

@@ -99,6 +99,7 @@ class KnowledgeGraph:
 
     def close(self):
         """Close the database connection."""
+        with self._lock:
             if self._connection is not None:
                 self._connection.close()
                 self._connection = None

tests/test_kg_thread_safety.py

@@ -0,0 +1,13 @@
+"""TDD: KnowledgeGraph.close() must hold self._lock."""
+
+import inspect
+from mempalace.knowledge_graph import KnowledgeGraph
+
+
+class TestKGCloseLock:
+    def test_close_holds_lock(self):
+        src = inspect.getsource(KnowledgeGraph.close)
+        assert "self._lock" in src, (
+            "close() does not acquire self._lock. "
+            "Closing while a read/write is in progress can corrupt data."
+        )