From 50fde71f1ac0528f40ee216136b33fde41205ef2 Mon Sep 17 00:00:00 2001
From: Allan Haldane <allan.haldane@gmail.com>
Date: Sat, 17 Feb 2018 14:36:49 -0500
Subject: BUG: break cyclic refs in recursive closures

Fixes #10620
---
 numpy/lib/npyio.py | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'numpy/lib/npyio.py')

diff --git a/numpy/lib/npyio.py b/numpy/lib/npyio.py
index 096f1a3a4..73613d2a4 100644
--- a/numpy/lib/npyio.py
+++ b/numpy/lib/npyio.py
@@ -1109,6 +1109,11 @@ def loadtxt(fname, dtype=float, comments='#', delimiter=None,
     finally:
         if fown:
             fh.close()
+        # recursive closures have a cyclic reference to themselves, which
+        # requires gc to collect (gh-10620). To avoid this problem, for
+        # performance and PyPy friendliness, we break the cycle:
+        flatten_dtype_internal = None
+        pack_items = None
 
     if X is None:
         X = np.array([], dtype)
-- 
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