[Python-checkins] gh-85160: Reduce memory usage of `singledispatchmethod` (#107706)
AlexWaygood
webhook-mailer at python.org
Mon Aug 7 08:46:40 EDT 2023
https://github.com/python/cpython/commit/2ac103c346ffe9d0e4c146402ce215c5ce6c1ef2
commit: 2ac103c346ffe9d0e4c146402ce215c5ce6c1ef2
branch: main
author: Alex Waygood <Alex.Waygood at Gmail.com>
committer: AlexWaygood <Alex.Waygood at Gmail.com>
date: 2023-08-07T13:46:36+01:00
summary:
gh-85160: Reduce memory usage of `singledispatchmethod` (#107706)
A small followup to #107148
Co-authored-by: Serhiy Storchaka <storchaka at gmail.com>
files:
M Lib/functools.py
diff --git a/Lib/functools.py b/Lib/functools.py
index 2a8a69b3c527a..be44ccdae6b69 100644
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -928,14 +928,14 @@ class singledispatchmethod:
"""
def __init__(self, func):
- import weakref # see comment in singledispatch function
if not callable(func) and not hasattr(func, "__get__"):
raise TypeError(f"{func!r} is not callable or a descriptor")
self.dispatcher = singledispatch(func)
self.func = func
+
+ import weakref # see comment in singledispatch function
self._method_cache = weakref.WeakKeyDictionary()
- self._all_weakrefable_instances = True
def register(self, cls, method=None):
"""generic_method.register(cls, func) -> func
@@ -945,11 +945,11 @@ def register(self, cls, method=None):
return self.dispatcher.register(cls, func=method)
def __get__(self, obj, cls=None):
- if self._all_weakrefable_instances:
+ if self._method_cache is not None:
try:
_method = self._method_cache[obj]
except TypeError:
- self._all_weakrefable_instances = False
+ self._method_cache = None
except KeyError:
pass
else:
@@ -963,7 +963,7 @@ def _method(*args, **kwargs):
_method.register = self.register
update_wrapper(_method, self.func)
- if self._all_weakrefable_instances:
+ if self._method_cache is not None:
self._method_cache[obj] = _method
return _method
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