fix(sandbox): prevent memory leak in file operation locks using WeakValueDictionary (#2096)

* fix(sandbox): prevent memory leak in file operation locks using WeakValueDictionary

* lint: fix lint issue in sandbox tools security

backend/packages/harness/deerflow/sandbox/file_operation_lock.py

@@ -1,8 +1,12 @@
 import threading
+import weakref
 
 from deerflow.sandbox.sandbox import Sandbox
 
-_FILE_OPERATION_LOCKS: dict[tuple[str, str], threading.Lock] = {}
+# Use WeakValueDictionary to prevent memory leak in long-running processes.
+# Locks are automatically removed when no longer referenced by any thread.
+_LockKey = tuple[str, str]
+_FILE_OPERATION_LOCKS: weakref.WeakValueDictionary[_LockKey, threading.Lock] = weakref.WeakValueDictionary()
 _FILE_OPERATION_LOCKS_GUARD = threading.Lock()
 
 

backend/tests/test_sandbox_tools_security.py

@@ -1018,3 +1018,39 @@ def test_str_replace_and_append_on_same_path_should_preserve_both_updates(monkey
 
     assert failures == []
     assert sandbox.content == "ALPHA\ntail\n"
+
+
+def test_file_operation_lock_memory_cleanup() -> None:
+    """Verify that released locks are eventually cleaned up by WeakValueDictionary.
+
+    This ensures that the sandbox component doesn't leak memory over time when
+    operating on many unique file paths.
+    """
+    import gc
+
+    from deerflow.sandbox.file_operation_lock import _FILE_OPERATION_LOCKS, get_file_operation_lock
+
+    class MockSandbox:
+        id = "test_cleanup_sandbox"
+
+    test_path = "/tmp/deer-flow/memory_leak_test_file.txt"
+    lock_key = (MockSandbox.id, test_path)
+
+    # 确保测试开始前 key 不存在
+    assert lock_key not in _FILE_OPERATION_LOCKS
+
+    def _use_lock_and_release() -> None:
+        # Create and acquire the lock within this scope
+        lock = get_file_operation_lock(MockSandbox(), test_path)
+        with lock:
+            pass
+        # As soon as this function returns, the local 'lock' variable is destroyed.
+        # Its reference count goes to zero, triggering WeakValueDictionary cleanup.
+
+    _use_lock_and_release()
+
+    # Force a garbage collection to be absolutely sure
+    gc.collect()
+
+    # 检查特定 key 是否被清理（而不是检查总长度）
+    assert lock_key not in _FILE_OPERATION_LOCKS