diff --git a/Lib/tempfile.py b/Lib/tempfile.py index 5e3ccab5f48502..53d14ff5c67131 100644 --- a/Lib/tempfile.py +++ b/Lib/tempfile.py @@ -656,7 +656,7 @@ def TemporaryFile(mode='w+b', buffering=-1, encoding=None, fd = None def opener(*args): nonlocal fd - flags2 = (flags | _os.O_TMPFILE) & ~_os.O_CREAT + flags2 = (flags | _os.O_TMPFILE) & ~_os.O_CREAT & ~_os.O_EXCL fd = _os.open(dir, flags2, 0o600) return fd try: diff --git a/Lib/test/test_tempfile.py b/Lib/test/test_tempfile.py index 52b13b98cbcce5..36151b016ea35b 100644 --- a/Lib/test/test_tempfile.py +++ b/Lib/test/test_tempfile.py @@ -1594,6 +1594,29 @@ def test_unexpected_error(self): mock_close.assert_called() self.assertEqual(os.listdir(dir), []) + @unittest.skipUnless(tempfile._O_TMPFILE_WORKS, 'need os.O_TMPFILE') + @unittest.skipUnless(os.path.exists('/proc/self/fd'), + 'need /proc/self/fd') + def test_link_tmpfile(self): + dir = tempfile.mkdtemp() + self.addCleanup(os_helper.rmtree, dir) + filename = os.path.join(dir, "link") + + with tempfile.TemporaryFile('w', dir=dir) as tmp: + # the flag can become False on Linux <= 3.11 + if not tempfile._O_TMPFILE_WORKS: + self.skipTest("O_TMPFILE doesn't work") + + tmp.write("hello") + tmp.flush() + fd = tmp.fileno() + + os.link(f'/proc/self/fd/{fd}', + filename, + follow_symlinks=True) + with open(filename) as fp: + self.assertEqual(fp.read(), "hello") + # Helper for test_del_on_shutdown class NulledModules: diff --git a/Misc/NEWS.d/next/Library/2025-07-04-12-53-02.gh-issue-136156.OYlXoz.rst b/Misc/NEWS.d/next/Library/2025-07-04-12-53-02.gh-issue-136156.OYlXoz.rst new file mode 100644 index 00000000000000..95606790e991a4 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2025-07-04-12-53-02.gh-issue-136156.OYlXoz.rst @@ -0,0 +1,3 @@ +:func:`tempfile.TemporaryFile` no longer uses :data:`os.O_EXCL` with +:data:`os.O_TMPFILE`, so it's possible to use ``linkat()`` on the file +descriptor. Patch by Victor Stinner.