bpo-29532: Altering a kwarg dictionary passed to functools.partial() no longer affects a partial object after creation. (#209)

serhiy-storchaka · web-flow · commit e48fd93bbb36 · 2017-02-21T18:18:27.000+02:00
diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py
@@ -89,6 +89,15 @@ def func(a=10, b=20):
         p(b=7)
         self.assertEqual(d, {'a':3})
 
+    def test_kwargs_copy(self):
+        # Issue #29532: Altering a kwarg dictionary passed to a constructor
+        # should not affect a partial object after creation
+        d = {'a': 3}
+        p = self.partial(capture, **d)
+        self.assertEqual(p(), ((), {'a': 3}))
+        d['a'] = 5
+        self.assertEqual(p(), ((), {'a': 3}))
+
     def test_arg_combinations(self):
         # exercise special code paths for zero args in either partial
         # object or the caller
diff --git a/Misc/NEWS b/Misc/NEWS
@@ -66,6 +66,19 @@ Extension Modules
 Library
 -------
 
+- bpo-29532: Altering a kwarg dictionary passed to functools.partial()
+  no longer affects a partial object after creation.
+
+- bpo-22807: Add uuid.SafeUUID and uuid.UUID.is_safe to relay information from
+  the platform about whether generated UUIDs are generated with a
+  multiprocessing safe method.
+
+- bpo-29576: Improve some deprecations in importlib. Some deprecated methods
+  now emit DeprecationWarnings and have better descriptive messages.
+
+- bpo-29534: Fixed different behaviour of Decimal.from_float()
+  for _decimal and _pydecimal. Thanks Andrew Nester.
+
 - Issue #28556: Various updates to typing module: typing.Counter, typing.ChainMap,
   improved ABC caching, etc. Original PRs by Jelle Zijlstra, Ivan Levkivskyi,
   Manuel Krebber, and Łukasz Langa.
diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
@@ -88,10 +88,13 @@ partial_new(PyTypeObject *type, PyObject *args, PyObject *kw)
         if (kw == NULL) {
             pto->kw = PyDict_New();
         }
-        else {
+        else if (Py_REFCNT(kw) == 1) {
             Py_INCREF(kw);
             pto->kw = kw;
         }
+        else {
+            pto->kw = PyDict_Copy(kw);
+        }
     }
     else {
         pto->kw = PyDict_Copy(pkw);

Original file line number	Diff line number	Diff line change
`@@ -88,10 +88,13 @@ partial_new(PyTypeObject type, PyObject args, PyObject *kw)`
`88`	`88`	`if (kw == NULL) {`
`89`	`89`	`pto->kw = PyDict_New();`
`90`	`90`	`}`
`91`		`- else {`
	`91`	`+ else if (Py_REFCNT(kw) == 1) {`
`92`	`92`	`Py_INCREF(kw);`
`93`	`93`	`pto->kw = kw;`
`94`	`94`	`}`
	`95`	`+ else {`
	`96`	`+ pto->kw = PyDict_Copy(kw);`
	`97`	`+ }`
`95`	`98`	`}`
`96`	`99`	`else {`
`97`	`100`	`pto->kw = PyDict_Copy(pkw);`