[pull] main from python:main

Lib/test/test_os/test_os.py

@@ -1867,7 +1867,9 @@ def test_walk_bad_dir2(self):
 
         walk_it = self.walk(self.tmp1_path, follow_symlinks=True)
         if self.is_fwalk:
-            self.assertRaises(NotADirectoryError, next, walk_it)
+            with self.assertRaises(OSError) as cm:
+                next(walk_it)
+            self.assertIn(cm.exception.errno, (errno.ENOTDIR, errno.EINVAL))
         self.assertRaises(StopIteration, next, walk_it)
 
     @unittest.skipUnless(hasattr(os, "mkfifo"), 'requires os.mkfifo()')
@@ -2269,6 +2271,8 @@ def test_chown_with_root(self):
 
     @requires_non_root_user
     @unittest.skipUnless(len(all_users) > 1, "test needs and more than one user")
+    @unittest.skipIf(sys.platform == 'cygwin',
+                         'chown() can set any uid on Cygwin')
     def test_chown_without_permission(self):
         uid_1, uid_2 = all_users[:2]
         gid = os.stat(os_helper.TESTFN).st_gid
@@ -4051,10 +4055,11 @@ def test_timerfd_non_blocking(self):
         initial_expiration = 0.1
         os.timerfd_settime(fd, initial=initial_expiration, interval=0)
 
-        # read() raises OSError with errno is EAGAIN for non-blocking timer.
-        with self.assertRaises(OSError) as ctx:
-            self.read_count_signaled(fd)
-        self.assertEqual(ctx.exception.errno, errno.EAGAIN)
+        if sys.platform != 'cygwin':
+            # read() raises OSError with errno is EAGAIN for non-blocking timer.
+            with self.assertRaises(OSError) as ctx:
+                self.read_count_signaled(fd)
+            self.assertEqual(ctx.exception.errno, errno.EAGAIN)
 
         # Wait more than 0.1 seconds
         time.sleep(initial_expiration + 0.1)
@@ -4235,12 +4240,19 @@ def test_timerfd_ns_initval(self):
 
         # 2nd call
         next_expiration_ns, interval_ns2 = os.timerfd_settime_ns(fd, initial=initial_expiration_ns, interval=interval_ns)
-        self.assertEqual(interval_ns2, interval_ns)
+        CYGWIN = (sys.platform == 'cygwin')
+        if not CYGWIN:
+            self.assertEqual(interval_ns2, interval_ns)
+        else:
+            self.assertEqual(interval_ns2, 0)
         self.assertEqual(next_expiration_ns, initial_expiration_ns)
 
         # timerfd_gettime
         next_expiration_ns, interval_ns2 = os.timerfd_gettime_ns(fd)
-        self.assertEqual(interval_ns2, interval_ns)
+        if not CYGWIN:
+            self.assertEqual(interval_ns2, interval_ns)
+        else:
+            self.assertEqual(interval_ns2, 0)
         self.assertLessEqual(next_expiration_ns, initial_expiration_ns)
 
         self.assertAlmostEqual(next_expiration_ns, initial_expiration_ns, delta=limit_error)

Lib/test/test_os/test_posix.py

@@ -142,8 +142,8 @@ def test_initgroups(self):
         self.assertRaises(TypeError, posix.initgroups, "foo", 3, object())
 
         # If a non-privileged user invokes it, it should fail with OSError
-        # EPERM.
-        if os.getuid() != 0:
+        # EPERM. On Cygwin, initgroups(name, 13) does not fail.
+        if os.getuid() != 0 and sys.platform != 'cygwin':
             try:
                 name = pwd.getpwuid(posix.getuid()).pw_name
             except KeyError:
@@ -597,7 +597,9 @@ def test_sysconf(self):
             posix.sysconf(1.23)
 
         arg_max = posix.sysconf("SC_ARG_MAX")
-        self.assertGreater(arg_max, 0)
+        # SC_ARG_MAX is -1 on Cygwin
+        if sys.platform != 'cygwin':
+            self.assertGreater(arg_max, 0)
         self.assertEqual(
             posix.sysconf(posix.sysconf_names["SC_ARG_MAX"]), arg_max)
 
@@ -1943,6 +1945,14 @@ def test_no_such_executable(self):
         # directories in the $PATH that are not accessible.
         except (FileNotFoundError, PermissionError) as exc:
             self.assertEqual(exc.filename, no_such_executable)
+
+            # On Cygwin, os.posix_spawn() creates a child process even if the
+            # executable doesn't exist. We have to reap this process.
+            if sys.platform == 'cygwin':
+                for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
+                    pid, status = os.waitpid(-1, os.WNOHANG)
+                    if pid != 0:
+                        break
         else:
             pid2, status = os.waitpid(pid, 0)
             self.assertEqual(pid2, pid)

Lib/test/test_socket.py

@@ -1454,7 +1454,7 @@ def testIPv6toString(self):
         assertInvalid('1:2:3:4:5:6:')
         assertInvalid('1:2:3:4:5:6:7:8:0')
         # bpo-29972: inet_pton() doesn't fail on AIX
-        if not AIX:
+        if not AIX and sys.platform != 'cygwin':
             assertInvalid('1:2:3:4:5:6:7:8:')
 
         self.assertEqual(b'\x00' * 12 + b'\xfe\x2a\x17\x40',
@@ -2001,7 +2001,8 @@ def test_getfqdn_filter_localhost(self):
         self.assertEqual(socket.getfqdn(), socket.getfqdn("::"))
 
     @unittest.skipUnless(socket_helper.IPV6_ENABLED, 'IPv6 required for this test.')
-    @unittest.skipIf(sys.platform == 'win32', 'does not work on Windows')
+    @unittest.skipIf(sys.platform in ('win32', 'cygwin'),
+                     'does not work on Windows')
     @unittest.skipIf(AIX, 'Symbolic scope id does not work')
     @unittest.skipUnless(hasattr(socket, 'if_nameindex'), "test needs socket.if_nameindex()")
     @support.skip_android_selinux('if_nameindex')
@@ -2035,7 +2036,7 @@ def test_getaddrinfo_ipv6_scopeid_numeric(self):
         self.assertEqual(sockaddr, ('ff02::1de:c0:face:8d', 1234, 0, ifindex))
 
     @unittest.skipUnless(socket_helper.IPV6_ENABLED, 'IPv6 required for this test.')
-    @unittest.skipIf(sys.platform == 'win32', 'does not work on Windows')
+    @unittest.skipIf(sys.platform in ('win32', 'cygwin'), 'does not work on Windows')
     @unittest.skipIf(AIX, 'Symbolic scope id does not work')
     @unittest.skipUnless(hasattr(socket, 'if_nameindex'), "test needs socket.if_nameindex()")
     @support.skip_android_selinux('if_nameindex')

Misc/NEWS.d/next/Core_and_Builtins/2026-05-16-11-03-54.gh-issue-149816.X_gqMT.rst

@@ -0,0 +1 @@
+Fix a race condition in ``_PyBytes_FromList`` in free-threading mode.

Modules/socketmodule.c

@@ -654,10 +654,6 @@ class _socket.socket "PySocketSockObject *" "clinic_state()->sock_type"
 [clinic start generated code]*/
 /*[clinic end generated code: output=da39a3ee5e6b4b0d input=2db2489bd2219fd8]*/
 
-#define clinic_state() (find_module_state_by_def(type))
-#include "clinic/socketmodule.c.h"
-#undef clinic_state
-
 /* XXX There's a problem here: *static* functions are not supposed to have
    a Py prefix (or use CapitalizedWords).  Later... */
 
@@ -688,6 +684,18 @@ class _socket.socket "PySocketSockObject *" "clinic_state()->sock_type"
 #define IS_SELECTABLE(s) (_PyIsSelectable_fd((s)->sock_fd) || (s)->sock_timeout <= 0)
 #endif
 
+// SCM_RIGHTS, sendmsg(), recvmsg() and sethostname() don't work properly on
+// Cygwin: disable these features.
+#ifdef __CYGWIN__
+#  undef CMSG_LEN
+#  undef SCM_RIGHTS
+#  undef HAVE_SETHOSTNAME
+#endif
+
+#define clinic_state() (find_module_state_by_def(type))
+#include "clinic/socketmodule.c.h"
+#undef clinic_state
+
 static PyObject*
 select_error(void)
 {

Objects/bytesobject.c

@@ -11,6 +11,7 @@
 #include "pycore_global_objects.h"// _Py_GET_GLOBAL_OBJECT()
 #include "pycore_initconfig.h"    // _PyStatus_OK()
 #include "pycore_long.h"          // _PyLong_DigitValue
+#include "pycore_list.h"          // _PyList_GetItemRef
 #include "pycore_object.h"        // _PyObject_GC_TRACK
 #include "pycore_pymem.h"         // PYMEM_CLEANBYTE
 #include "pycore_strhex.h"        // _Py_strhex_with_sep()
@@ -2991,8 +2992,10 @@ _PyBytes_FromList(PyObject *x)
     size = _PyBytesWriter_GetAllocated(writer);
 
     for (Py_ssize_t i = 0; i < PyList_GET_SIZE(x); i++) {
-        PyObject *item = PyList_GET_ITEM(x, i);
-        Py_INCREF(item);
+        PyObject *item = _PyList_GetItemRef((PyListObject *)x, i);
+        if (item == NULL) {
+            goto error;
+        }
         Py_ssize_t value = PyNumber_AsSsize_t(item, NULL);
         Py_DECREF(item);
         if (value == -1 && PyErr_Occurred())