From 8a10e080b5c7a7ca39601012298d15eec95c04b8 Mon Sep 17 00:00:00 2001
From: Sang Min Park <sangmin.park@gmail.com>
Date: Fri, 31 May 2019 10:55:08 -0400
Subject: [PATCH] #3225: document

---
 flask/cli.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/flask/cli.py b/flask/cli.py
index fdd0b765..44f31c9d 100644
--- a/flask/cli.py
+++ b/flask/cli.py
@@ -132,6 +132,8 @@ def _called_with_wrong_args(factory):
         # didn't reach the factory
         return True
     finally:
+        # explicitly delete tb as it is circular referenced
+        # https://docs.python.org/2/library/sys.html#sys.exc_info
         del tb