[Python-checkins] bpo-31581: Reduce the number of imports for functools (GH-3757)
INADA Naoki
webhook-mailer at python.org
Sat Sep 30 03:13:05 EDT 2017
https://github.com/python/cpython/commit/9811e80fd0ed9d74c76a66f1dd4e4b8afa9e8f53
commit: 9811e80fd0ed9d74c76a66f1dd4e4b8afa9e8f53
branch: master
author: INADA Naoki <methane at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2017-09-30T16:13:02+09:00
summary:
bpo-31581: Reduce the number of imports for functools (GH-3757)
files:
M Lib/functools.py
M Lib/test/test_functools.py
diff --git a/Lib/functools.py b/Lib/functools.py
index 25075de5b40..a51dddf8785 100644
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -19,8 +19,7 @@
pass
from abc import get_cache_token
from collections import namedtuple
-from types import MappingProxyType
-from weakref import WeakKeyDictionary
+# import types, weakref # Deferred to single_dispatch()
from reprlib import recursive_repr
from _thread import RLock
@@ -753,10 +752,14 @@ def singledispatch(func):
function acts as the default implementation, and additional
implementations can be registered using the register() attribute of the
generic function.
-
"""
+ # There are many programs that use functools without singledispatch, so we
+ # trade-off making singledispatch marginally slower for the benefit of
+ # making start-up of such applications slightly faster.
+ import types, weakref
+
registry = {}
- dispatch_cache = WeakKeyDictionary()
+ dispatch_cache = weakref.WeakKeyDictionary()
cache_token = None
def dispatch(cls):
@@ -803,7 +806,7 @@ def wrapper(*args, **kw):
registry[object] = func
wrapper.register = register
wrapper.dispatch = dispatch
- wrapper.registry = MappingProxyType(registry)
+ wrapper.registry = types.MappingProxyType(registry)
wrapper._clear_cache = dispatch_cache.clear
update_wrapper(wrapper, func)
return wrapper
diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py
index f7a11666133..68e94e7ae17 100644
--- a/Lib/test/test_functools.py
+++ b/Lib/test/test_functools.py
@@ -2019,6 +2019,8 @@ def _(arg):
def test_cache_invalidation(self):
from collections import UserDict
+ import weakref
+
class TracingDict(UserDict):
def __init__(self, *args, **kwargs):
super(TracingDict, self).__init__(*args, **kwargs)
@@ -2033,90 +2035,89 @@ def __setitem__(self, key, value):
self.data[key] = value
def clear(self):
self.data.clear()
- _orig_wkd = functools.WeakKeyDictionary
+
td = TracingDict()
- functools.WeakKeyDictionary = lambda: td
- c = collections.abc
- @functools.singledispatch
- def g(arg):
- return "base"
- d = {}
- l = []
- self.assertEqual(len(td), 0)
- self.assertEqual(g(d), "base")
- self.assertEqual(len(td), 1)
- self.assertEqual(td.get_ops, [])
- self.assertEqual(td.set_ops, [dict])
- self.assertEqual(td.data[dict], g.registry[object])
- self.assertEqual(g(l), "base")
- self.assertEqual(len(td), 2)
- self.assertEqual(td.get_ops, [])
- self.assertEqual(td.set_ops, [dict, list])
- self.assertEqual(td.data[dict], g.registry[object])
- self.assertEqual(td.data[list], g.registry[object])
- self.assertEqual(td.data[dict], td.data[list])
- self.assertEqual(g(l), "base")
- self.assertEqual(g(d), "base")
- self.assertEqual(td.get_ops, [list, dict])
- self.assertEqual(td.set_ops, [dict, list])
- g.register(list, lambda arg: "list")
- self.assertEqual(td.get_ops, [list, dict])
- self.assertEqual(len(td), 0)
- self.assertEqual(g(d), "base")
- self.assertEqual(len(td), 1)
- self.assertEqual(td.get_ops, [list, dict])
- self.assertEqual(td.set_ops, [dict, list, dict])
- self.assertEqual(td.data[dict],
- functools._find_impl(dict, g.registry))
- self.assertEqual(g(l), "list")
- self.assertEqual(len(td), 2)
- self.assertEqual(td.get_ops, [list, dict])
- self.assertEqual(td.set_ops, [dict, list, dict, list])
- self.assertEqual(td.data[list],
- functools._find_impl(list, g.registry))
- class X:
- pass
- c.MutableMapping.register(X) # Will not invalidate the cache,
- # not using ABCs yet.
- self.assertEqual(g(d), "base")
- self.assertEqual(g(l), "list")
- self.assertEqual(td.get_ops, [list, dict, dict, list])
- self.assertEqual(td.set_ops, [dict, list, dict, list])
- g.register(c.Sized, lambda arg: "sized")
- self.assertEqual(len(td), 0)
- self.assertEqual(g(d), "sized")
- self.assertEqual(len(td), 1)
- self.assertEqual(td.get_ops, [list, dict, dict, list])
- self.assertEqual(td.set_ops, [dict, list, dict, list, dict])
- self.assertEqual(g(l), "list")
- self.assertEqual(len(td), 2)
- self.assertEqual(td.get_ops, [list, dict, dict, list])
- self.assertEqual(td.set_ops, [dict, list, dict, list, dict, list])
- self.assertEqual(g(l), "list")
- self.assertEqual(g(d), "sized")
- self.assertEqual(td.get_ops, [list, dict, dict, list, list, dict])
- self.assertEqual(td.set_ops, [dict, list, dict, list, dict, list])
- g.dispatch(list)
- g.dispatch(dict)
- self.assertEqual(td.get_ops, [list, dict, dict, list, list, dict,
- list, dict])
- self.assertEqual(td.set_ops, [dict, list, dict, list, dict, list])
- c.MutableSet.register(X) # Will invalidate the cache.
- self.assertEqual(len(td), 2) # Stale cache.
- self.assertEqual(g(l), "list")
- self.assertEqual(len(td), 1)
- g.register(c.MutableMapping, lambda arg: "mutablemapping")
- self.assertEqual(len(td), 0)
- self.assertEqual(g(d), "mutablemapping")
- self.assertEqual(len(td), 1)
- self.assertEqual(g(l), "list")
- self.assertEqual(len(td), 2)
- g.register(dict, lambda arg: "dict")
- self.assertEqual(g(d), "dict")
- self.assertEqual(g(l), "list")
- g._clear_cache()
- self.assertEqual(len(td), 0)
- functools.WeakKeyDictionary = _orig_wkd
+ with support.swap_attr(weakref, "WeakKeyDictionary", lambda: td):
+ c = collections.abc
+ @functools.singledispatch
+ def g(arg):
+ return "base"
+ d = {}
+ l = []
+ self.assertEqual(len(td), 0)
+ self.assertEqual(g(d), "base")
+ self.assertEqual(len(td), 1)
+ self.assertEqual(td.get_ops, [])
+ self.assertEqual(td.set_ops, [dict])
+ self.assertEqual(td.data[dict], g.registry[object])
+ self.assertEqual(g(l), "base")
+ self.assertEqual(len(td), 2)
+ self.assertEqual(td.get_ops, [])
+ self.assertEqual(td.set_ops, [dict, list])
+ self.assertEqual(td.data[dict], g.registry[object])
+ self.assertEqual(td.data[list], g.registry[object])
+ self.assertEqual(td.data[dict], td.data[list])
+ self.assertEqual(g(l), "base")
+ self.assertEqual(g(d), "base")
+ self.assertEqual(td.get_ops, [list, dict])
+ self.assertEqual(td.set_ops, [dict, list])
+ g.register(list, lambda arg: "list")
+ self.assertEqual(td.get_ops, [list, dict])
+ self.assertEqual(len(td), 0)
+ self.assertEqual(g(d), "base")
+ self.assertEqual(len(td), 1)
+ self.assertEqual(td.get_ops, [list, dict])
+ self.assertEqual(td.set_ops, [dict, list, dict])
+ self.assertEqual(td.data[dict],
+ functools._find_impl(dict, g.registry))
+ self.assertEqual(g(l), "list")
+ self.assertEqual(len(td), 2)
+ self.assertEqual(td.get_ops, [list, dict])
+ self.assertEqual(td.set_ops, [dict, list, dict, list])
+ self.assertEqual(td.data[list],
+ functools._find_impl(list, g.registry))
+ class X:
+ pass
+ c.MutableMapping.register(X) # Will not invalidate the cache,
+ # not using ABCs yet.
+ self.assertEqual(g(d), "base")
+ self.assertEqual(g(l), "list")
+ self.assertEqual(td.get_ops, [list, dict, dict, list])
+ self.assertEqual(td.set_ops, [dict, list, dict, list])
+ g.register(c.Sized, lambda arg: "sized")
+ self.assertEqual(len(td), 0)
+ self.assertEqual(g(d), "sized")
+ self.assertEqual(len(td), 1)
+ self.assertEqual(td.get_ops, [list, dict, dict, list])
+ self.assertEqual(td.set_ops, [dict, list, dict, list, dict])
+ self.assertEqual(g(l), "list")
+ self.assertEqual(len(td), 2)
+ self.assertEqual(td.get_ops, [list, dict, dict, list])
+ self.assertEqual(td.set_ops, [dict, list, dict, list, dict, list])
+ self.assertEqual(g(l), "list")
+ self.assertEqual(g(d), "sized")
+ self.assertEqual(td.get_ops, [list, dict, dict, list, list, dict])
+ self.assertEqual(td.set_ops, [dict, list, dict, list, dict, list])
+ g.dispatch(list)
+ g.dispatch(dict)
+ self.assertEqual(td.get_ops, [list, dict, dict, list, list, dict,
+ list, dict])
+ self.assertEqual(td.set_ops, [dict, list, dict, list, dict, list])
+ c.MutableSet.register(X) # Will invalidate the cache.
+ self.assertEqual(len(td), 2) # Stale cache.
+ self.assertEqual(g(l), "list")
+ self.assertEqual(len(td), 1)
+ g.register(c.MutableMapping, lambda arg: "mutablemapping")
+ self.assertEqual(len(td), 0)
+ self.assertEqual(g(d), "mutablemapping")
+ self.assertEqual(len(td), 1)
+ self.assertEqual(g(l), "list")
+ self.assertEqual(len(td), 2)
+ g.register(dict, lambda arg: "dict")
+ self.assertEqual(g(d), "dict")
+ self.assertEqual(g(l), "list")
+ g._clear_cache()
+ self.assertEqual(len(td), 0)
if __name__ == '__main__':
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