[Python-checkins] bpo-44553 : Implement GC methods for types.Union (GH-26993)
miss-islington
webhook-mailer at python.org
Sat Jul 3 09:33:50 EDT 2021
https://github.com/python/cpython/commit/0856134542c1067d02c9027ddbb2a61916907e92
commit: 0856134542c1067d02c9027ddbb2a61916907e92
branch: 3.10
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: miss-islington <31488909+miss-islington at users.noreply.github.com>
date: 2021-07-03T06:33:16-07:00
summary:
bpo-44553 : Implement GC methods for types.Union (GH-26993)
(cherry picked from commit 1097384ce964dd63686b1aac706cd0fa764c2dc9)
Co-authored-by: Ken Jin <28750310+Fidget-Spinner at users.noreply.github.com>
files:
A Misc/NEWS.d/next/Core and Builtins/2021-07-02-22-54-41.bpo-44553.l9YqGg.rst
M Lib/test/test_types.py
M Objects/unionobject.c
diff --git a/Lib/test/test_types.py b/Lib/test/test_types.py
index d3e315a196b51..ae7b17bd590e6 100644
--- a/Lib/test/test_types.py
+++ b/Lib/test/test_types.py
@@ -1,8 +1,9 @@
# Python test set -- part 6, built-in types
-from test.support import run_with_locale
+from test.support import run_with_locale, cpython_only
import collections.abc
from collections import namedtuple
+import gc
import inspect
import pickle
import locale
@@ -756,6 +757,23 @@ def __module__(self):
with self.assertRaises(ZeroDivisionError):
str | TypeVar()
+ @cpython_only
+ def test_or_type_operator_reference_cycle(self):
+ if not hasattr(sys, 'gettotalrefcount'):
+ self.skipTest('Cannot get total reference count.')
+ gc.collect()
+ before = sys.gettotalrefcount()
+ for _ in range(30):
+ T = typing.TypeVar('T')
+ U = int | list[T]
+ T.blah = U
+ del T
+ del U
+ gc.collect()
+ leeway = 15
+ self.assertLessEqual(sys.gettotalrefcount() - before, leeway,
+ msg='Check for union reference leak.')
+
def test_ellipsis_type(self):
self.assertIsInstance(Ellipsis, types.EllipsisType)
diff --git a/Misc/NEWS.d/next/Core and Builtins/2021-07-02-22-54-41.bpo-44553.l9YqGg.rst b/Misc/NEWS.d/next/Core and Builtins/2021-07-02-22-54-41.bpo-44553.l9YqGg.rst
new file mode 100644
index 0000000000000..e97df02994806
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2021-07-02-22-54-41.bpo-44553.l9YqGg.rst
@@ -0,0 +1,2 @@
+Implement GC methods for ``types.Union`` to break reference cycles and
+prevent memory leaks.
diff --git a/Objects/unionobject.c b/Objects/unionobject.c
index a66d61524dcfc..cc7181d2475ca 100644
--- a/Objects/unionobject.c
+++ b/Objects/unionobject.c
@@ -1,5 +1,6 @@
// types.Union -- used to represent e.g. Union[int, str], int | str
#include "Python.h"
+#include "pycore_object.h" // _PyObject_GC_TRACK/UNTRACK
#include "pycore_unionobject.h"
#include "structmember.h"
@@ -14,10 +15,20 @@ unionobject_dealloc(PyObject *self)
{
unionobject *alias = (unionobject *)self;
+ _PyObject_GC_UNTRACK(self);
+
Py_XDECREF(alias->args);
Py_TYPE(self)->tp_free(self);
}
+static int
+union_traverse(PyObject *self, visitproc visit, void *arg)
+{
+ unionobject *alias = (unionobject *)self;
+ Py_VISIT(alias->args);
+ return 0;
+}
+
static Py_hash_t
union_hash(PyObject *self)
{
@@ -437,8 +448,9 @@ PyTypeObject _Py_UnionType = {
.tp_basicsize = sizeof(unionobject),
.tp_dealloc = unionobject_dealloc,
.tp_alloc = PyType_GenericAlloc,
- .tp_free = PyObject_Del,
- .tp_flags = Py_TPFLAGS_DEFAULT,
+ .tp_free = PyObject_GC_Del,
+ .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
+ .tp_traverse = union_traverse,
.tp_hash = union_hash,
.tp_getattro = PyObject_GenericGetAttr,
.tp_members = union_members,
@@ -472,15 +484,16 @@ _Py_Union(PyObject *args)
}
}
- result = PyObject_New(unionobject, &_Py_UnionType);
+ result = PyObject_GC_New(unionobject, &_Py_UnionType);
if (result == NULL) {
return NULL;
}
result->args = dedup_and_flatten_args(args);
if (result->args == NULL) {
- Py_DECREF(result);
+ PyObject_GC_Del(result);
return NULL;
}
+ _PyObject_GC_TRACK(result);
return (PyObject*)result;
}
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