From: Raymond Hettinger <python@rcn.com>
Date: Sat, 17 Mar 2012 00:04:11 +0000 (-0700)
Subject: Unique sentinel value for cache.get()
X-Git-Tag: v3.3.0a2~138
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=d37fb559102d9c20786d8578a0362d1cd44aada2;p=thirdparty%2FPython%2Fcpython.git

Unique sentinel value for cache.get()
---

diff --git a/Lib/functools.py b/Lib/functools.py
index adc79274ca34..3eb55c6458b1 100644
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -175,8 +175,8 @@ def lru_cache(maxsize=100, typed=False):
                 # simple caching without ordering or size limit
                 nonlocal hits, misses
                 key = make_key(args, kwds, typed) if kwds or typed else args
-                result = cache_get(key)
-                if result is not None:
+                result = cache_get(key, root)   # root used here as a unique not-found sentinel        
+                if result is not root:
                     hits += 1
                     return result
                 result = user_function(*args, **kwds)