bpo-38006: Avoid closure in weakref.WeakValueDictionary (GH-15641)

vstinner · web-flow · commit a2af05a0d3f0 · 2019-09-09T16:55:58.000+02:00
weakref.WeakValueDictionary defines a local remove() function used as
callback for weak references. This function was created with a
closure.  Modify the implementation to avoid the closure.
diff --git a/Lib/test/test_weakref.py b/Lib/test/test_weakref.py
@@ -1792,6 +1792,11 @@ def test_threaded_weak_value_dict_deepcopy(self):
         # copying should not result in a crash.
         self.check_threaded_weak_dict_copy(weakref.WeakValueDictionary, True)
 
+    @support.cpython_only
+    def test_remove_closure(self):
+        d = weakref.WeakValueDictionary()
+        self.assertIsNone(d._remove.__closure__)
+
 
 from test import mapping_tests
 
diff --git a/Lib/weakref.py b/Lib/weakref.py
@@ -108,12 +108,12 @@ def remove(wr, selfref=ref(self), _atomic_removal=_remove_dead_weakref):
                 else:
                     # Atomic removal is necessary since this function
                     # can be called asynchronously by the GC
-                    _atomic_removal(d, wr.key)
+                    _atomic_removal(self.data, wr.key)
         self._remove = remove
         # A list of keys to be removed
         self._pending_removals = []
         self._iterating = set()
-        self.data = d = {}
+        self.data = {}
         self.update(other, **kw)
 
     def _commit_removals(self):
diff --git a/Misc/NEWS.d/next/Library/2019-09-02-13-37-27.bpo-38006.Y7vA0Q.rst b/Misc/NEWS.d/next/Library/2019-09-02-13-37-27.bpo-38006.Y7vA0Q.rst
@@ -0,0 +1,3 @@
+weakref.WeakValueDictionary defines a local remove() function used as
+callback for weak references. This function was created with a closure.
+Modify the implementation to avoid the closure.

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+weakref.WeakValueDictionary defines a local remove() function used as`
	`2`	`+callback for weak references. This function was created with a closure.`
	`3`	`+Modify the implementation to avoid the closure.`