Issue #28991: Fix obscure reentrancy bug in functools.lru_cache().
diff --git a/Lib/functools.py b/Lib/functools.py
index 214523c..60cf3c4 100644
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -516,14 +516,16 @@
last = root[PREV]
link = [last, root, key, result]
last[NEXT] = root[PREV] = cache[key] = link
- full = (len(cache) >= maxsize)
+ # Use the __len__() method instead of the len() function
+ # which could potentially be wrapped in an lru_cache itself.
+ full = (cache.__len__() >= maxsize)
misses += 1
return result
def cache_info():
"""Report cache statistics"""
with lock:
- return _CacheInfo(hits, misses, maxsize, len(cache))
+ return _CacheInfo(hits, misses, maxsize, cache.__len__())
def cache_clear():
"""Clear the cache and cache statistics"""