From e8632b041ade3ba0f1c2b5ea9c2378118cd3e5d9 Mon Sep 17 00:00:00 2001
From: Unal Ege Gaznepoglu <ege.gaznepoglu@fau.de>
Date: Thu, 24 Oct 2024 12:48:42 +0200
Subject: [PATCH] Add a comment regarding reference cycles

---
 tensordict/_td.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tensordict/_td.py b/tensordict/_td.py
index 6a6b2040f..2785b7da4 100644
--- a/tensordict/_td.py
+++ b/tensordict/_td.py
@@ -978,6 +978,8 @@ def _cast_reduction(
                     agglomerate, keepdim=keepdim, dim=dim
                 )
 
+        # IMPORTANT: do not directly access batch_dims (or any other property)
+        # via self.batch_dims otherwise a reference cycle is introduced
         def proc_dim(dim, batch_dims, tuple_ok=True):
             if dim is None:
                 return dim