merge from master

python · giampaolo · Apr 2, 2023 · Mar 10, 2019 · Mar 10, 2019 · Mar 10, 2019
commit 3c4af91c1e7c02561efa752885011ff642725bd8
diff --git a/Doc/whatsnew/3.8.rst b/Doc/whatsnew/3.8.rst
@@ -850,6 +850,105 @@ Changes in the Python API
   :attr:`unittest.TestResult.collectedDurations` attribute.
   (Contributed by Giampaolo Rodola in :issue:`4080`)
 
+* :func:`~os.path.expanduser` on Windows now prefers the :envvar:`USERPROFILE`
+  environment variable and does not use :envvar:`HOME`, which is not normally
+  set for regular user accounts.
+
+.. _bpo-36085-whatsnew:
+
+* DLL dependencies for extension modules and DLLs loaded with :mod:`ctypes` on
+  Windows are now resolved more securely. Only the system paths, the directory
+  containing the DLL or PYD file, and directories added with
+  :func:`~os.add_dll_directory` are searched for load-time dependencies.
+  Specifically, :envvar:`PATH` and the current working directory are no longer
+  used, and modifications to these will no longer have any effect on normal DLL
+  resolution. If your application relies on these mechanisms, you should check
+  for :func:`~os.add_dll_directory` and if it exists, use it to add your DLLs
+  directory while loading your library. Note that Windows 7 users will need to
+  ensure that Windows Update KB2533625 has been installed (this is also verified
+  by the installer).
+  (See :issue:`36085`.)
+
+* The header files and functions related to pgen have been removed after its
+  replacement by a pure Python implementation. (Contributed by Pablo Galindo
+  in :issue:`36623`.)
+
+
+Changes in the C API
+--------------------
+
+* On Unix, C extensions are no longer linked to libpython. When Python is
+  embedded, ``libpython`` must not be loaded with ``RTLD_LOCAL``, but
+  ``RTLD_GLOBAL`` instead. Previously, using ``RTLD_LOCAL``, it was already not
+  possible to load C extensions which were not linked to ``libpython``, like C
+  extensions of the standard library built by the ``*shared*`` section of
+  ``Modules/Setup``.
+
+* Use of ``#`` variants of formats in parsing or building value (e.g.
+  :c:func:`PyArg_ParseTuple`, :c:func:`Py_BuildValue`, :c:func:`PyObject_CallFunction`,
+  etc.) without ``PY_SSIZE_T_CLEAN`` defined raises ``DeprecationWarning`` now.
+  It will be removed in 3.10 or 4.0.  Read :ref:`arg-parsing` for detail.
+  (Contributed by Inada Naoki in :issue:`36381`.)
+
+* Instances of heap-allocated types (such as those created with
+  :c:func:`PyType_FromSpec`) hold a reference to their type object.
+  Increasing the reference count of these type objects has been moved from
+  :c:func:`PyType_GenericAlloc` to the more low-level functions,
+  :c:func:`PyObject_Init` and :c:func:`PyObject_INIT`.
+  This makes types created through :c:func:`PyType_FromSpec` behave like
+  other classes in managed code.
+
+  Statically allocated types are not affected.
+
+  For the vast majority of cases, there should be no side effect.
+  However, types that manually increase the reference count after allocating
+  an instance (perhaps to work around the bug) may now become immortal.
+  To avoid this, these classes need to call Py_DECREF on the type object
+  during instance deallocation.
+
+  To correctly port these types into 3.8, please apply the following
+  changes:
+
+  * Remove :c:macro:`Py_INCREF` on the type object after allocating an
+    instance - if any.
+    This may happen after calling :c:func:`PyObject_New`,
+    :c:func:`PyObject_NewVar`, :c:func:`PyObject_GC_New`,
+    :c:func:`PyObject_GC_NewVar`, or any other custom allocator that uses
+    :c:func:`PyObject_Init` or :c:func:`PyObject_INIT`.
+
+    Example::
+
+        static foo_struct *
+        foo_new(PyObject *type) {
+            foo_struct *foo = PyObject_GC_New(foo_struct, (PyTypeObject *) type);
+            if (foo == NULL)
+                return NULL;
+        #if PY_VERSION_HEX < 0x03080000
+            // Workaround for Python issue 35810; no longer necessary in Python 3.8
+            PY_INCREF(type)
+        #endif
+            return foo;
+        }
+
+  * Ensure that all custom ``tp_dealloc`` functions of heap-allocated types
+    decrease the type's reference count.
+
+    Example::
+
+        static void
+        foo_dealloc(foo_struct *instance) {
+            PyObject *type = Py_TYPE(instance);
+            PyObject_GC_Del(instance);
+        #if PY_VERSION_HEX >= 0x03080000
+            // This was not needed before Python 3.8 (Python issue 35810)
+            Py_DECREF(type);
+        #endif
+        }
+
+  (Contributed by Eddie Elizondo in :issue:`35810`.)
+
+>>>>>>> master
+
 CPython bytecode changes
 ------------------------