New submission from STINNER Victor <vstin...@redhat.com>:
ctypes._reset_cache() contains the following code:
# XXX for whatever reasons, creating the first instance of a callback
# function is needed for the unittests on Win64 to succeed. This MAY
# be a compiler bug, since the problem occurs only when _ctypes is
# compiled with the MS SDK compiler. Or an uninitialized variable?
CFUNCTYPE(c_int)(lambda: None)
This code has been added 11 years ago:
commit 674e9389e9fdadd622829f4833367ac3b38475b5
Author: Thomas Heller <thel...@ctypes.org>
Date: Fri Aug 31 13:06:44 2007 +0000
Add a workaround for a strange bug on win64, when _ctypes is compiled
with the SDK compiler. This should fix the failing
Lib\ctypes\test\test_as_parameter.py test.
diff --git a/Lib/ctypes/__init__.py b/Lib/ctypes/__init__.py
index cdf6d36e47..f55d194b8f 100644
--- a/Lib/ctypes/__init__.py
+++ b/Lib/ctypes/__init__.py
@@ -535,3 +535,9 @@ for kind in [c_ushort, c_uint, c_ulong, c_ulonglong]:
elif sizeof(kind) == 4: c_uint32 = kind
elif sizeof(kind) == 8: c_uint64 = kind
del(kind)
+
+# XXX for whatever reasons, creating the first instance of a callback
+# function is needed for the unittests on Win64 to succeed. This MAY
+# be a compiler bug, since the problem occurs only when _ctypes is
+# compiled with the MS SDK compiler. Or an uninitialized variable?
+CFUNCTYPE(c_int)(lambda: None)
--
This call is removed from Fedora package by the following patch:
https://src.fedoraproject.org/rpms/python3/blob/master/f/00155-avoid-ctypes-thunks.patch
Extract of Fedora python3.spec:
# 00155 #
# Avoid allocating thunks in ctypes unless absolutely necessary, to avoid
# generating SELinux denials on "import ctypes" and "import uuid" when
# embedding Python within httpd
# See https://bugzilla.redhat.com/show_bug.cgi?id=814391
Patch155: 00155-avoid-ctypes-thunks.patch
The patch has been added 6 years ago in Fedora:
commit 8a28107df1670a03a12cf6a7787160f103d8d8c8
Author: David Malcolm <dmalc...@redhat.com>
Date: Fri Apr 20 15:28:39 2012 -0400
3.2.3-4: avoid allocating thunks in ctypes unless absolutely necessary
(patch 155; rhbz#814391)
* Fri Apr 20 2012 David Malcolm <dmalc...@redhat.com> - 3.2.3-4
- avoid allocating thunks in ctypes unless absolutely necessary, to avoid
generating SELinux denials on "import ctypes" and "import uuid" when
embedding
Python within httpd (patch 155; rhbz#814391)
https://src.fedoraproject.org/rpms/python3/c/8a28107df1670a03a12cf6a7787160f103d8d8c8?branch=master
--
I don't understand the purpose of the workaround and ctypes is working well on
Fedora. I propose to also remove the workaround in the master branch.
In case of doubt, I prefer to keep the workaround in Python 3.7.
Attached PR removes the workaround.
----------
components: Library (Lib)
messages: 332054
nosy: vstinner
priority: normal
severity: normal
status: open
title: Remove ctypes old workaround: creating the first instance of a callback
versions: Python 3.8
_______________________________________
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue35523>
_______________________________________
_______________________________________________
Python-bugs-list mailing list
Unsubscribe:
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
