Python 3.9.0a4

Include/patchlevel.h

@@ -20,10 +20,10 @@
 #define PY_MINOR_VERSION        9
 #define PY_MICRO_VERSION        0
 #define PY_RELEASE_LEVEL        PY_RELEASE_LEVEL_ALPHA
-#define PY_RELEASE_SERIAL       3
+#define PY_RELEASE_SERIAL       4
 
 /* Version as a string */
-#define PY_VERSION              "3.9.0a3+"
+#define PY_VERSION              "3.9.0a4"
 /*--end constants--*/
 
 /* Version as a single 4-byte hex number, e.g. 0x010502B2 == 1.5.2b2.

Lib/pydoc_data/topics.py

 # -*- coding: utf-8 -*-
-# Autogenerated by Sphinx on Fri Jan 24 22:03:37 2020
+# Autogenerated by Sphinx on Tue Feb 25 13:20:31 2020
 topics = {'assert': 'The "assert" statement\n'
            '**********************\n'
            '\n'
@@ -5291,9 +5291,12 @@
                   'Changed in version 3.6: Added the "\'_\'" option (see also '
                   '**PEP 515**).\n'
                   '\n'
-                  '*width* is a decimal integer defining the minimum field '
-                  'width.  If not\n'
-                  'specified, then the field width will be determined by the '
+                  '*width* is a decimal integer defining the minimum total '
+                  'field width,\n'
+                  'including any prefixes, separators, and other formatting '
+                  'characters.\n'
+                  'If not specified, then the field width will be determined '
+                  'by the\n'
                   'content.\n'
                   '\n'
                   'When no explicit alignment is given, preceding the *width* '
@@ -9005,11 +9008,17 @@
                  'bases,\n'
                  '**kwds)" (where the additional keyword arguments, if any, '
                  'come from\n'
-                 'the class definition).\n'
+                 'the class definition). The "__prepare__" method should be '
+                 'implemented\n'
+                 'as a "classmethod()". The namespace returned by '
+                 '"__prepare__" is\n'
+                 'passed in to "__new__", but when the final class object is '
+                 'created the\n'
+                 'namespace is copied into a new "dict".\n'
                  '\n'
                  'If the metaclass has no "__prepare__" attribute, then the '
                  'class\n'
-                 'namespace is initialised as an empty ordered mapping.\n'
+                 'namespace is initialised as an empty "dict()".\n'
                  '\n'
                  'See also:\n'
                  '\n'

Misc/NEWS.d/next/Build/2020-01-29-19-17-02.bpo-39489.HKPzv-.rst

-Remove ``COUNT_ALLOCS`` special build.

Misc/NEWS.d/next/C API/2020-01-07-13-46-40.bpo-39245.G7wog6.rst

-The Vectorcall API (PEP 590) was made public, adding the functions
-``PyObject_Vectorcall``, ``PyObject_VectorcallMethod``,
-``PyVectorcall_Function``, ``PyObject_CallOneArg``,
-``PyObject_CallMethodNoArgs``, ``PyObject_CallMethodOneArg``,
-``PyObject_FastCallDict``, and the flag ``Py_TPFLAGS_HAVE_VECTORCALL``.

Misc/NEWS.d/next/C API/2020-01-17-11-37-05.bpo-38076.cxfw2x.rst

-Fix to clear the interpreter state only after clearing module globals to
-guarantee module state access from C Extensions during runtime destruction

Misc/NEWS.d/next/C API/2020-01-31-16-35-21.bpo-39511.nv9yEn.rst

-The :c:func:`PyThreadState_Clear` function now calls the
-:c:member:`PyThreadState.on_delete` callback. Previously, that happened in
-:c:func:`PyThreadState_Delete`.

Misc/NEWS.d/next/C API/2020-02-05-12-00-18.bpo-39542.RJCUKR.rst

-Exclude trashcan mechanism from the limited C API: it requires access to
-PyTypeObject and PyThreadState structure fields, whereas these structures
-are opaque in the limited C API.

Misc/NEWS.d/next/C API/2020-02-05-12-40-51.bpo-39542.si-_Zq.rst

-In the limited C API, ``PyObject_INIT()`` and ``PyObject_INIT_VAR()`` are
-now defined as aliases to :c:func:`PyObject_Init` and
-:c:func:`PyObject_InitVar` to make their implementation opaque. It avoids to
-leak implementation details in the limited C API. Exclude the following
-functions from the limited C API: ``_Py_NewReference()``,
-``_Py_ForgetReference()``, ``_PyTraceMalloc_NewReference()`` and
-``_Py_GetRefTotal()``.

Misc/NEWS.d/next/C API/2020-02-05-13-14-20.bpo-39542.5mleGX.rst

-Convert :c:func:`PyType_HasFeature`, :c:func:`PyType_Check` and
-:c:func:`PyType_CheckExact` macros to static inline functions.

Misc/NEWS.d/next/C API/2020-02-07-00-23-44.bpo-39573.nRD1q7.rst

-Add a :c:func:`Py_SET_REFCNT` function to set the reference counter of an
-object.

Misc/NEWS.d/next/C API/2020-02-07-03-39-03.bpo-39573.Oa8cL1.rst

-Add :c:func:`Py_SET_TYPE` function to set the type of an object.

Misc/NEWS.d/next/C API/2020-02-07-09-35-43.bpo-39500.xRAEgX.rst

-:c:func:`PyUnicode_IsIdentifier` does not call :c:func:`Py_FatalError`
-anymore if the string is not ready.

Misc/NEWS.d/next/C API/2020-02-07-10-41-53.bpo-39573.EG9VDI.rst

-Add :c:func:`Py_SET_SIZE` function to set the size of an object.

Misc/NEWS.d/next/C API/2020-02-12-21-24-02.bpo-35081.at7BjN.rst

-Move the ``dtoa.h`` header file to the internal C API as ``pycore_dtoa.h``:
-it only contains private functions (prefixed by ``_Py``). The :mod:`math` and
-:mod:`cmath` modules must now be compiled with the ``Py_BUILD_CORE`` macro
-defined.
-

Misc/NEWS.d/next/C API/2020-02-12-21-38-49.bpo-35081.5tj1yC.rst

-Move the ``bytes_methods.h`` header file to the internal C API as
-``pycore_bytes_methods.h``: it only contains private symbols (prefixed by
-``_Py``), except of the ``PyDoc_STRVAR_shared()`` macro.

Misc/NEWS.d/next/Core and Builtins/2018-02-16-10-44-24.bpo-32856.UjR8SD.rst

-Optimized the idiom for assignment a temporary variable in comprehensions.
-Now ``for y in [expr]`` in comprehensions is as fast as a simple assignment
-``y = expr``.

Misc/NEWS.d/next/Core and Builtins/2019-03-02-23-03-34.bpo-36144.LRl4LS.rst

-:class:`dict` (and :class:`collections.UserDict`) objects now support PEP 584's merge (``|``) and update (``|=``) operators.
-Patch by Brandt Bucher.

Misc/NEWS.d/next/Core and Builtins/2019-06-09-10-54-31.bpo-37207.bLjgLR.rst

-Speed up calls to ``range()`` by about 30%, by using the
-PEP 590 ``vectorcall`` calling convention. Patch by Mark Shannon.

Misc/NEWS.d/next/Core and Builtins/2019-12-03-16-41-22.bpo-38960.kvoFM0.rst

-Fix DTrace build issues on FreeBSD. Patch by David Carlier.