Merge branch '0.29.x'

CHANGES.rst

@@ -454,6 +454,10 @@ Other changes
 Bugs fixed
 ----------
 
+* Now uses ``Py_SET_SIZE()`` and ``Py_SET_REFCNT()`` in Py3.9+ to avoid low-level
+  write access to these object fields.
+  Patch by Victor Stinner.  (Github issue #3639)
+
 * The built-in ``abs()`` function could lead to undefined behaviour when used on
   the negative-most value of a signed C integer type.
   Patch by Serge Guelton.  (Github issue #1911)

Cython/Compiler/ModuleNode.py

@@ -2040,6 +2040,10 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
         if scope.directives['c_api_binop_methods']:
             code.putln('#define %s %s' % (func_name, slot.left_slot.slot_code(scope)))
             return
+        else:
+            error(self.pos,
+                  "The 'c_api_binop_methods' directive is only supported for forward compatibility"
+                  " and must be True.")
 
         code.putln()
         preprocessor_guard = slot.preprocessor_guard_code()

Cython/Utility/ModuleSetupCode.c

@@ -830,6 +830,15 @@ static CYTHON_INLINE PyObject * __Pyx_PyDict_GetItemStrWithError(PyObject *dict,
 #endif
 
 
+#if PY_VERSION_HEX >= 0x030900A4
+  #define __Pyx_SET_REFCNT(obj, refcnt) Py_SET_REFCNT(obj, refcnt)
+  #define __Pyx_SET_SIZE(obj, size) Py_SET_SIZE(obj, size)
+#else
+  #define __Pyx_SET_REFCNT(obj, refcnt) Py_REFCNT(obj) = (refcnt)
+  #define __Pyx_SET_SIZE(obj, size) Py_SIZE(obj) = (size)
+#endif
+
+
 #if PY_VERSION_HEX >= 0x030900A4
   #define __Pyx_SET_REFCNT(obj, refcnt) Py_SET_REFCNT(obj, refcnt)
   #define __Pyx_SET_SIZE(obj, size) Py_SET_SIZE(obj, size)

tests/run/binop_reverse_methods_GH2056.pyx

-cimport cython
-
-@cython.c_api_binop_methods(False)
-@cython.cclass
-class Base(object):
-    """
-    >>> Base() + 2
-    'Base.__add__(Base(), 2)'
-    >>> 2 + Base()
-    'Base.__radd__(Base(), 2)'
-
-    >>> Base() ** 2
-    'Base.__pow__(Base(), 2, None)'
-    >>> 2 ** Base()
-    'Base.__rpow__(Base(), 2, None)'
-    >>> pow(Base(), 2, 100)
-    'Base.__pow__(Base(), 2, 100)'
-    """
-    def __add__(self, other):
-        return "Base.__add__(%s, %s)" % (self, other)
-
-    def __radd__(self, other):
-        return "Base.__radd__(%s, %s)" % (self, other)
-
-    def __pow__(self, other, mod):
-        return "Base.__pow__(%s, %s, %s)" % (self, other, mod)
-
-    def __rpow__(self, other, mod):
-        return "Base.__rpow__(%s, %s, %s)" % (self, other, mod)
-
-    def __repr__(self):
-        return "%s()" % (self.__class__.__name__)
-
-@cython.c_api_binop_methods(False)
-@cython.cclass
-class OverloadLeft(Base):
-    """
-    >>> OverloadLeft() + 2
-    'OverloadLeft.__add__(OverloadLeft(), 2)'
-    >>> 2 + OverloadLeft()
-    'Base.__radd__(OverloadLeft(), 2)'
-
-    >>> OverloadLeft() + Base()
-    'OverloadLeft.__add__(OverloadLeft(), Base())'
-    >>> Base() + OverloadLeft()
-    'Base.__add__(Base(), OverloadLeft())'
-    """
-    def __add__(self, other):
-        return "OverloadLeft.__add__(%s, %s)" % (self, other)
-
-
-@cython.c_api_binop_methods(False)
-@cython.cclass
-class OverloadRight(Base):
-    """
-    >>> OverloadRight() + 2
-    'Base.__add__(OverloadRight(), 2)'
-    >>> 2 + OverloadRight()
-    'OverloadRight.__radd__(OverloadRight(), 2)'
-
-    >>> OverloadRight() + Base()
-    'Base.__add__(OverloadRight(), Base())'
-    >>> Base() + OverloadRight()
-    'OverloadRight.__radd__(OverloadRight(), Base())'
-    """
-    def __radd__(self, other):
-        return "OverloadRight.__radd__(%s, %s)" % (self, other)
-
-@cython.c_api_binop_methods(True)
-@cython.cclass
-class OverloadCApi(Base):
-    """
-    >>> OverloadCApi() + 2
-    'OverloadCApi.__add__(OverloadCApi(), 2)'
-    >>> 2 + OverloadCApi()
-    'OverloadCApi.__add__(2, OverloadCApi())'
-
-    >>> OverloadCApi() + Base()
-    'OverloadCApi.__add__(OverloadCApi(), Base())'
-    >>> Base() + OverloadCApi()
-    'OverloadCApi.__add__(Base(), OverloadCApi())'
-    """
-    def __add__(self, other):
-        return "OverloadCApi.__add__(%s, %s)" % (self, other)
-