Issue #13374: The Windows bytes API has been deprecated in the os module. Use

Unicode filenames instead of bytes filenames to not depend on the ANSI code
page anymore and to support any filename.

8 files changed, 262 insertions, 167 deletions

diff --git a/Doc/whatsnew/3.3.rst b/Doc/whatsnew/3.3.rst
index 7e877fc..7be122d 100644
--- a/Doc/whatsnew/3.3.rst
+++ b/Doc/whatsnew/3.3.rst
@@ -573,6 +573,10 @@ Porting Python code
   with sys.platform.startswith('linux'), or directly sys.platform == 'linux' if
   you don't need to support older Python versions.
 
+* Issue #13374: The Windows bytes API has been deprecated in the :mod:`os`
+  module. Use Unicode filenames instead of bytes filenames to not depend on the
+  ANSI code page anymore and to support any filename.
+
 Porting C code
 --------------
 
diff --git a/Lib/test/test_genericpath.py b/Lib/test/test_genericpath.py
index 50638a1..b618d45 100644
--- a/Lib/test/test_genericpath.py
+++ b/Lib/test/test_genericpath.py
@@ -2,11 +2,12 @@
 Tests common to genericpath, macpath, ntpath and posixpath
 """
 
-import unittest
-from test import support
-import os
 import genericpath
+import os
 import sys
+import unittest
+import warnings
+from test import support
 
 
 def safe_rmdir(dirname):
@@ -258,7 +259,9 @@ class CommonTest(GenericTest):
 
     def test_abspath(self):
         self.assertIn("foo", self.pathmodule.abspath("foo"))
-        self.assertIn(b"foo", self.pathmodule.abspath(b"foo"))
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore", DeprecationWarning)
+            self.assertIn(b"foo", self.pathmodule.abspath(b"foo"))
 
         # Abspath returns bytes when the arg is bytes
         for path in (b'', b'foo', b'f\xf2\xf2', b'/foo', b'C:\\'):
@@ -266,7 +269,9 @@ class CommonTest(GenericTest):
 
     def test_realpath(self):
         self.assertIn("foo", self.pathmodule.realpath("foo"))
-        self.assertIn(b"foo", self.pathmodule.realpath(b"foo"))
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore", DeprecationWarning)
+            self.assertIn(b"foo", self.pathmodule.realpath(b"foo"))
 
     def test_normpath_issue5827(self):
         # Make sure normpath preserves unicode
@@ -296,8 +301,10 @@ class CommonTest(GenericTest):
         "Mac OS X denies the creation of a directory with an invalid utf8 name")
     def test_nonascii_abspath(self):
         # Test non-ASCII, non-UTF8 bytes in the path.
-        with support.temp_cwd(b'\xe7w\xf0'):
-            self.test_abspath()
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore", DeprecationWarning)
+            with support.temp_cwd(b'\xe7w\xf0'):
+                self.test_abspath()
 
 
 def test_main():
diff --git a/Lib/test/test_ntpath.py b/Lib/test/test_ntpath.py
index 6464950..2c9dab9 100644
--- a/Lib/test/test_ntpath.py
+++ b/Lib/test/test_ntpath.py
@@ -1,10 +1,11 @@
 import ntpath
 import os
 import sys
+import unittest
+import warnings
 from test.support import TestFailed
 from test import support, test_genericpath
 from tempfile import TemporaryFile
-import unittest
 
 
 def tester(fn, wantResult):
@@ -21,7 +22,9 @@ def tester(fn, wantResult):
     fn = fn.replace('["', '[b"')
     fn = fn.replace(", '", ", b'")
     fn = fn.replace(', "', ', b"')
-    gotResult = eval(fn)
+    with warnings.catch_warnings():
+        warnings.simplefilter("ignore", DeprecationWarning)
+        gotResult = eval(fn)
     if isinstance(wantResult, str):
         wantResult = wantResult.encode('ascii')
     elif isinstance(wantResult, tuple):
diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index da143cf..ec2877e 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -213,7 +213,9 @@ class StatAttributeTests(unittest.TestCase):
             fname = self.fname.encode(sys.getfilesystemencoding())
         except UnicodeEncodeError:
             self.skipTest("cannot encode %a for the filesystem" % self.fname)
-        self.check_stat_attributes(fname)
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore", DeprecationWarning)
+            self.check_stat_attributes(fname)
 
     def test_statvfs_attributes(self):
         if not hasattr(os, "statvfs"):
@@ -838,7 +840,9 @@ class LinkTests(unittest.TestCase):
         with open(file1, "w") as f1:
             f1.write("test")
 
-        os.link(file1, file2)
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore", DeprecationWarning)
+            os.link(file1, file2)
         with open(file1, "r") as f1, open(file2, "r") as f2:
             self.assertTrue(os.path.sameopenfile(f1.fileno(), f2.fileno()))
 
@@ -1160,8 +1164,10 @@ class Win32SymlinkTests(unittest.TestCase):
         self.assertNotEqual(os.lstat(link), os.stat(link))
 
         bytes_link = os.fsencode(link)
-        self.assertEqual(os.stat(bytes_link), os.stat(target))
-        self.assertNotEqual(os.lstat(bytes_link), os.stat(bytes_link))
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore", DeprecationWarning)
+            self.assertEqual(os.stat(bytes_link), os.stat(target))
+            self.assertNotEqual(os.lstat(bytes_link), os.stat(bytes_link))
 
     def test_12084(self):
         level1 = os.path.abspath(support.TESTFN)
@@ -1619,6 +1625,35 @@ class ExtendedAttributeTests(unittest.TestCase):
         self._check_xattrs(getxattr, setxattr, removexattr, listxattr)
 
 
+@unittest.skipUnless(sys.platform == "win32", "Win32 specific tests")
+class Win32DeprecatedBytesAPI(unittest.TestCase):
+    def test_deprecated(self):
+        import nt
+        filename = os.fsencode(support.TESTFN)
+        with warnings.catch_warnings():
+            warnings.simplefilter("error", DeprecationWarning)
+            for func, *args in (
+                (nt._getfullpathname, filename),
+                (nt._isdir, filename),
+                (os.access, filename, os.R_OK),
+                (os.chdir, filename),
+                (os.chmod, filename, 0o777),
+                (os.link, filename, filename),
+                (os.listdir, filename),
+                (os.lstat, filename),
+                (os.mkdir, filename),
+                (os.open, filename, os.O_RDONLY),
+                (os.rename, filename, filename),
+                (os.rmdir, filename),
+                (os.startfile, filename),
+                (os.stat, filename),
+                (os.symlink, filename, filename),
+                (os.unlink, filename),
+                (os.utime, filename),
+            ):
+                self.assertRaises(DeprecationWarning, func, *args)
+
+
 @support.reap_threads
 def test_main():
     support.run_unittest(
@@ -1643,6 +1678,7 @@ def test_main():
         TestSendfile,
         ProgramPriorityTests,
         ExtendedAttributeTests,
+        Win32DeprecatedBytesAPI,
     )
 
 if __name__ == "__main__":
diff --git a/Lib/test/test_pep277.py b/Lib/test/test_pep277.py
index a1a4791..4b16cbb 100644
--- a/Lib/test/test_pep277.py
+++ b/Lib/test/test_pep277.py
@@ -1,6 +1,9 @@
 # Test the Unicode versions of normal file functions
 # open, os.open, os.stat. os.listdir, os.rename, os.remove, os.mkdir, os.chdir, os.rmdir
-import sys, os, unittest
+import os
+import sys
+import unittest
+import warnings
 from unicodedata import normalize
 from test import support
 
@@ -155,7 +158,9 @@ class UnicodeFileTests(unittest.TestCase):
     @unittest.skipIf(sys.platform == 'darwin', 'irrelevant test on Mac OS X')
     def test_listdir(self):
         sf0 = set(self.files)
-        f1 = os.listdir(support.TESTFN.encode(sys.getfilesystemencoding()))
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore", DeprecationWarning)
+            f1 = os.listdir(support.TESTFN.encode(sys.getfilesystemencoding()))
         f2 = os.listdir(support.TESTFN)
         sf2 = set(os.path.join(support.TESTFN, f) for f in f2)
         self.assertEqual(sf0, sf2, "%a != %a" % (sf0, sf2))
diff --git a/Lib/test/test_posixpath.py b/Lib/test/test_posixpath.py
index bb4559c..709ef04 100644
--- a/Lib/test/test_posixpath.py
+++ b/Lib/test/test_posixpath.py
@@ -1,10 +1,10 @@
-import unittest
-from test import support, test_genericpath
-
-import posixpath
 import os
+import posixpath
 import sys
+import unittest
+import warnings
 from posixpath import realpath, abspath, dirname, basename
+from test import support, test_genericpath
 
 try:
     import posix
@@ -231,7 +231,9 @@ class PosixPathTest(unittest.TestCase):
 
     def test_ismount(self):
         self.assertIs(posixpath.ismount("/"), True)
-        self.assertIs(posixpath.ismount(b"/"), True)
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore", DeprecationWarning)
+            self.assertIs(posixpath.ismount(b"/"), True)
 
     def test_ismount_non_existent(self):
         # Non-existent mountpoint.
diff --git a/Misc/NEWS b/Misc/NEWS
index 3ed7e7a..6e77935 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -374,6 +374,10 @@ Core and Builtins
 Library
 -------
 
+- Issue #13374: The Windows bytes API has been deprecated in the os module. Use
+  Unicode filenames instead of bytes filenames to not depend on the ANSI code
+  page anymore and to support any filename.
+
 - Issue #13297: Use bytes type to send and receive binary data through XMLRPC.
 
 - Issue #6397: Support "/dev/poll" polling objects in select module,
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 26fc25f..9012e39 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -546,6 +546,34 @@ win32_get_reparse_tag(HANDLE reparse_point_handle, ULONG *reparse_tag)
 
     return TRUE;
 }
+
+static int
+win32_warn_bytes_api()
+{
+    return PyErr_WarnEx(PyExc_DeprecationWarning,
+        "The Windows bytes API has been deprecated, "
+        "use Unicode filenames instead",
+        1);
+}
+
+static PyObject*
+win32_decode_filename(PyObject *obj)
+{
+    PyObject *unicode;
+    if (PyUnicode_Check(obj)) {
+        if (PyUnicode_READY(obj))
+            return NULL;
+        Py_INCREF(obj);
+        return obj;
+    }
+    if (!PyUnicode_FSDecoder(obj, &unicode))
+        return NULL;
+    if (win32_warn_bytes_api()) {
+        Py_DECREF(unicode);
+        return NULL;
+    }
+    return unicode;
+}
 #endif /* MS_WINDOWS */
 
 /* Return a dictionary corresponding to the POSIX environment table */
@@ -725,22 +753,6 @@ win32_error_object(char* function, PyObject* filename)
         return PyErr_SetFromWindowsErr(errno);
 }
 
-static int
-convert_to_unicode(PyObject **param)
-{
-    if (PyUnicode_CheckExact(*param))
-        Py_INCREF(*param);
-    else if (PyUnicode_Check(*param))
-        /* For a Unicode subtype that's not a Unicode object,
-           return a true Unicode object with the same data. */
-        *param = PyUnicode_Copy(*param);
-    else
-        *param = PyUnicode_FromEncodedObject(*param,
-                                             Py_FileSystemDefaultEncoding,
-                                             "strict");
-    return (*param) != NULL;
-}
-
 #endif /* MS_WINDOWS */
 
 #if defined(PYOS_OS2)
@@ -895,7 +907,7 @@ win32_1str(PyObject* args, char* func,
            char* wformat, BOOL (__stdcall *funcW)(LPWSTR))
 {
     PyObject *uni;
-    char *ansi;
+    const char *ansi;
     BOOL result;
 
     if (PyArg_ParseTuple(args, wformat, &uni))
@@ -915,6 +927,8 @@ win32_1str(PyObject* args, char* func,
 
     if (!PyArg_ParseTuple(args, format, &ansi))
         return NULL;
+    if (win32_warn_bytes_api())
+        return NULL;
     Py_BEGIN_ALLOW_THREADS
     result = funcA(ansi);
     Py_END_ALLOW_THREADS
@@ -1129,14 +1143,15 @@ attributes_from_dir_w(LPCWSTR pszFile, BY_HANDLE_FILE_INFORMATION *info, ULONG *
 
 /* Grab GetFinalPathNameByHandle dynamically from kernel32 */
 static int has_GetFinalPathNameByHandle = 0;
-static DWORD (CALLBACK *Py_GetFinalPathNameByHandleA)(HANDLE, LPSTR, DWORD,
-                                                      DWORD);
 static DWORD (CALLBACK *Py_GetFinalPathNameByHandleW)(HANDLE, LPWSTR, DWORD,
                                                       DWORD);
 static int
 check_GetFinalPathNameByHandle()
 {
     HINSTANCE hKernel32;
+    DWORD (CALLBACK *Py_GetFinalPathNameByHandleA)(HANDLE, LPSTR, DWORD,
+                                                   DWORD);
+
     /* only recheck */
     if (!has_GetFinalPathNameByHandle)
     {
@@ -1853,6 +1868,12 @@ posix_do_stat(PyObject *self, PyObject *args,
     if (!PyArg_ParseTuple(args, format,
                           PyUnicode_FSConverter, &opath))
         return NULL;
+#ifdef MS_WINDOWS
+    if (win32_warn_bytes_api()) {
+        Py_DECREF(opath);
+        return NULL;
+    }
+#endif
     path = PyBytes_AsString(opath);
     Py_BEGIN_ALLOW_THREADS
     res = (*statfunc)(path, &st);
@@ -1885,8 +1906,7 @@ existence, or the inclusive-OR of R_OK, W_OK, and X_OK.");
 static PyObject *
 posix_access(PyObject *self, PyObject *args)
 {
-    PyObject *opath;
-    char *path;
+    const char *path;
     int mode;
 
 #ifdef MS_WINDOWS
@@ -1904,14 +1924,13 @@ posix_access(PyObject *self, PyObject *args)
     /* Drop the argument parsing error as narrow strings
        are also valid. */
     PyErr_Clear();
-    if (!PyArg_ParseTuple(args, "O&i:access",
-                          PyUnicode_FSConverter, &opath, &mode))
+    if (!PyArg_ParseTuple(args, "yi:access", &path, &mode))
+        return NULL;
+    if (win32_warn_bytes_api())
         return NULL;
-    path = PyBytes_AsString(opath);
     Py_BEGIN_ALLOW_THREADS
     attr = GetFileAttributesA(path);
     Py_END_ALLOW_THREADS
-    Py_DECREF(opath);
 finish:
     if (attr == 0xFFFFFFFF)
         /* File does not exist, or cannot read attributes */
@@ -1923,6 +1942,7 @@ finish:
                            || !(attr & FILE_ATTRIBUTE_READONLY)
                            || (attr & FILE_ATTRIBUTE_DIRECTORY));
 #else
+    PyObject *opath;
     int res;
     if (!PyArg_ParseTuple(args, "O&i:access",
                           PyUnicode_FSConverter, &opath, &mode))
@@ -2042,7 +2062,7 @@ static PyObject *
 posix_chmod(PyObject *self, PyObject *args)
 {
     PyObject *opath = NULL;
-    char *path = NULL;
+    const char *path = NULL;
     int i;
     int res;
 #ifdef MS_WINDOWS
@@ -2073,10 +2093,10 @@ posix_chmod(PyObject *self, PyObject *args)
        are also valid. */
     PyErr_Clear();
 
-    if (!PyArg_ParseTuple(args, "O&i:chmod", PyUnicode_FSConverter,
-                          &opath, &i))
+    if (!PyArg_ParseTuple(args, "yi:chmod", &path, &i))
+        return NULL;
+    if (win32_warn_bytes_api())
         return NULL;
-    path = PyBytes_AsString(opath);
     Py_BEGIN_ALLOW_THREADS
     attr = GetFileAttributesA(path);
     if (attr != 0xFFFFFFFF) {
@@ -2091,10 +2111,8 @@ posix_chmod(PyObject *self, PyObject *args)
     Py_END_ALLOW_THREADS
     if (!res) {
         win32_error("chmod", path);
-        Py_DECREF(opath);
         return NULL;
     }
-    Py_DECREF(opath);
     Py_INCREF(Py_None);
     return Py_None;
 #else /* MS_WINDOWS */
@@ -2450,51 +2468,56 @@ Create a hard link to a file.");
 static PyObject *
 win32_link(PyObject *self, PyObject *args)
 {
-    PyObject *osrc, *odst;
-    char *src, *dst;
-    BOOL rslt;
-    PyObject *usrc, *udst;
+    PyObject *src, *dst;
+    BOOL ok;
 
-    if (PyArg_ParseTuple(args, "UU:link", &usrc, &udst))
+    if (PyArg_ParseTuple(args, "UU:link", &src, &dst))
     {
         wchar_t *wsrc, *wdst;
-        wsrc = PyUnicode_AsUnicode(usrc);
+
+        wsrc = PyUnicode_AsUnicode(src);
         if (wsrc == NULL)
-            return NULL;
-        wdst = PyUnicode_AsUnicode(udst);
+            goto error;
+        wdst = PyUnicode_AsUnicode(dst);
         if (wdst == NULL)
-            return NULL;
+            goto error;
 
         Py_BEGIN_ALLOW_THREADS
-        rslt = CreateHardLinkW(wdst, wsrc, NULL);
+        ok = CreateHardLinkW(wdst, wsrc, NULL);
         Py_END_ALLOW_THREADS
 
-        if (rslt == 0)
+        if (!ok)
             return win32_error("link", NULL);
-
         Py_RETURN_NONE;
     }
+    else {
+        PyErr_Clear();
+        if (!PyArg_ParseTuple(args, "O&O&:link",
+                              PyUnicode_FSConverter, &src,
+                              PyUnicode_FSConverter, &dst))
+            return NULL;
 
-    /* Narrow strings also valid. */
-    PyErr_Clear();
-
-    if (!PyArg_ParseTuple(args, "O&O&:link", PyUnicode_FSConverter, &osrc,
-                          PyUnicode_FSConverter, &odst))
-        return NULL;
+        if (win32_warn_bytes_api())
+            goto error;
 
-    src = PyBytes_AsString(osrc);
-    dst = PyBytes_AsString(odst);
+        Py_BEGIN_ALLOW_THREADS
+        ok = CreateHardLinkA(PyBytes_AS_STRING(dst),
+                             PyBytes_AS_STRING(src),
+                             NULL);
+        Py_END_ALLOW_THREADS
 
-    Py_BEGIN_ALLOW_THREADS
-    rslt = CreateHardLinkA(dst, src, NULL);
-    Py_END_ALLOW_THREADS
+        Py_XDECREF(src);
+        Py_XDECREF(dst);
 
-    Py_DECREF(osrc);
-    Py_DECREF(odst);
-    if (rslt == 0)
-        return win32_error("link", NULL);
+        if (!ok)
+            return win32_error("link", NULL);
+        Py_RETURN_NONE;
 
-    Py_RETURN_NONE;
+    error:
+        Py_XDECREF(src);
+        Py_XDECREF(dst);
+        return NULL;
+    }
 }
 #endif /* MS_WINDOWS */
 
@@ -2519,7 +2542,8 @@ posix_listdir(PyObject *self, PyObject *args)
     HANDLE hFindFile;
     BOOL result;
     WIN32_FIND_DATA FileData;
-    PyObject *opath;
+    const char *path;
+    Py_ssize_t pathlen;
     char namebuf[MAX_PATH+5]; /* Overallocate for \\*.*\0 */
     char *bufptr = namebuf;
     Py_ssize_t len = sizeof(namebuf)-5; /* only claim to have space for MAX_PATH */
@@ -2613,17 +2637,16 @@ posix_listdir(PyObject *self, PyObject *args)
        are also valid. */
     PyErr_Clear();
 
-    if (!PyArg_ParseTuple(args, "O&:listdir",
-                          PyUnicode_FSConverter, &opath))
+    if (!PyArg_ParseTuple(args, "y#:listdir", &path, &pathlen))
         return NULL;
-    if (PyBytes_GET_SIZE(opath)+1 > MAX_PATH) {
+    if (win32_warn_bytes_api())
+        return NULL;
+    if (pathlen+1 > MAX_PATH) {
         PyErr_SetString(PyExc_ValueError, "path too long");
-        Py_DECREF(opath);
         return NULL;
     }
-    strcpy(namebuf, PyBytes_AsString(opath));
-    len = PyObject_Size(opath);
-    Py_DECREF(opath);
+    strcpy(namebuf, path);
+    len = pathlen;
     if (len > 0) {
         char ch = namebuf[len-1];
         if (ch != SEP && ch != ALTSEP && ch != ':')
@@ -2915,11 +2938,9 @@ posix_fdlistdir(PyObject *self, PyObject *args)
 static PyObject *
 posix__getfullpathname(PyObject *self, PyObject *args)
 {
-    PyObject *opath;
-    char *path;
+    const char *path;
     char outbuf[MAX_PATH*2];
     char *temp;
-#ifdef MS_WINDOWS
     PyObject *po;
 
     if (PyArg_ParseTuple(args, "U|:_getfullpathname", &po))
@@ -2953,19 +2974,17 @@ posix__getfullpathname(PyObject *self, PyObject *args)
     /* Drop the argument parsing error as narrow strings
        are also valid. */
     PyErr_Clear();
-#endif
 
-    if (!PyArg_ParseTuple (args, "O&:_getfullpathname",
-                           PyUnicode_FSConverter, &opath))
+    if (!PyArg_ParseTuple (args, "y:_getfullpathname",
+                           &path))
+        return NULL;
+    if (win32_warn_bytes_api())
         return NULL;
-    path = PyBytes_AsString(opath);
     if (!GetFullPathName(path, Py_ARRAY_LENGTH(outbuf),
                          outbuf, &temp)) {
         win32_error("GetFullPathName", path);
-        Py_DECREF(opath);
         return NULL;
     }
-    Py_DECREF(opath);
     if (PyUnicode_Check(PyTuple_GetItem(args, 0))) {
         return PyUnicode_Decode(outbuf, strlen(outbuf),
                                 Py_FileSystemDefaultEncoding, NULL);
@@ -3069,8 +3088,7 @@ PyDoc_STRVAR(posix__isdir__doc__,
 static PyObject *
 posix__isdir(PyObject *self, PyObject *args)
 {
-    PyObject *opath;
-    char *path;
+    const char *path;
     PyObject *po;
     DWORD attributes;
 
@@ -3088,11 +3106,10 @@ posix__isdir(PyObject *self, PyObject *args)
        are also valid. */
     PyErr_Clear();
 
-    if (!PyArg_ParseTuple(args, "O&:_isdir",
-                          PyUnicode_FSConverter, &opath))
+    if (!PyArg_ParseTuple(args, "y:_isdir", &path))
+        return NULL;
+    if (win32_warn_bytes_api())
         return NULL;
-
-    path = PyBytes_AsString(opath);
     attributes = GetFileAttributesA(path);
     if (attributes == INVALID_FILE_ATTRIBUTES)
         Py_RETURN_FALSE;
@@ -3113,8 +3130,7 @@ static PyObject *
 posix_mkdir(PyObject *self, PyObject *args)
 {
     int res;
-    PyObject *opath;
-    char *path;
+    const char *path;
     int mode = 0777;
 
 #ifdef MS_WINDOWS
@@ -3136,22 +3152,21 @@ posix_mkdir(PyObject *self, PyObject *args)
     /* Drop the argument parsing error as narrow strings
        are also valid. */
     PyErr_Clear();
-    if (!PyArg_ParseTuple(args, "O&|i:mkdir",
-                          PyUnicode_FSConverter, &opath, &mode))
+    if (!PyArg_ParseTuple(args, "y|i:mkdir", &path, &mode))
+        return NULL;
+    if (win32_warn_bytes_api())
         return NULL;
-    path = PyBytes_AsString(opath);
     Py_BEGIN_ALLOW_THREADS
     res = CreateDirectoryA(path, NULL);
     Py_END_ALLOW_THREADS
     if (!res) {
         win32_error("mkdir", path);
-        Py_DECREF(opath);
         return NULL;
     }
-    Py_DECREF(opath);
     Py_INCREF(Py_None);
     return Py_None;
 #else
+    PyObject *opath;
 
     if (!PyArg_ParseTuple(args, "O&|i:mkdir",
                           PyUnicode_FSConverter, &opath, &mode))
@@ -3265,44 +3280,54 @@ static PyObject *
 posix_rename(PyObject *self, PyObject *args)
 {
 #ifdef MS_WINDOWS
-    PyObject *o1, *o2;
-    wchar_t *w1, *w2;
-    char *p1, *p2;
+    PyObject *src, *dst;
     BOOL result;
-    if (!PyArg_ParseTuple(args, "OO:rename", &o1, &o2))
-        goto error;
-    if (!convert_to_unicode(&o1))
-        goto error;
-    if (!convert_to_unicode(&o2)) {
-        Py_DECREF(o1);
-        goto error;
+    if (PyArg_ParseTuple(args, "UU:rename", &src, &dst))
+    {
+        wchar_t *wsrc, *wdst;
+
+        wsrc = PyUnicode_AsUnicode(src);
+        if (wsrc == NULL)
+            return NULL;
+        wdst = PyUnicode_AsUnicode(dst);
+        if (wdst == NULL)
+            return NULL;
+        Py_BEGIN_ALLOW_THREADS
+        result = MoveFileW(wsrc, wdst);
+        Py_END_ALLOW_THREADS
+        if (!result)
+            return win32_error("rename", NULL);
+        Py_INCREF(Py_None);
+        return Py_None;
     }
-    w1 = PyUnicode_AsUnicode(o1);
-    if (w1 == NULL)
-        goto error;
-    w2 = PyUnicode_AsUnicode(o2);
-    if (w2 == NULL)
-        goto error;
-    Py_BEGIN_ALLOW_THREADS
-    result = MoveFileW(w1, w2);
-    Py_END_ALLOW_THREADS
-    Py_DECREF(o1);
-    Py_DECREF(o2);
-    if (!result)
-        return win32_error("rename", NULL);
-    Py_INCREF(Py_None);
-    return Py_None;
+    else {
+        PyErr_Clear();
+        if (!PyArg_ParseTuple(args, "O&O&:rename",
+                              PyUnicode_FSConverter, &src,
+                              PyUnicode_FSConverter, &dst))
+            return NULL;
+
+        if (win32_warn_bytes_api())
+            goto error;
+
+        Py_BEGIN_ALLOW_THREADS
+        result = MoveFileA(PyBytes_AS_STRING(src),
+                           PyBytes_AS_STRING(dst));
+        Py_END_ALLOW_THREADS
+
+        Py_XDECREF(src);
+        Py_XDECREF(dst);
+
+        if (!result)
+            return win32_error("rename", NULL);
+        Py_INCREF(Py_None);
+        return Py_None;
+
 error:
-    PyErr_Clear();
-    if (!PyArg_ParseTuple(args, "ss:rename", &p1, &p2))
+        Py_XDECREF(src);
+        Py_XDECREF(dst);
         return NULL;
-    Py_BEGIN_ALLOW_THREADS
-    result = MoveFileA(p1, p2);
-    Py_END_ALLOW_THREADS
-    if (!result)
-        return win32_error("rename", NULL);
-    Py_INCREF(Py_None);
-    return Py_None;
+    }
 #else
     return posix_2str(args, "O&O&:rename", rename);
 #endif
@@ -3546,8 +3571,7 @@ posix_utime(PyObject *self, PyObject *args)
     PyObject *arg = Py_None;
     PyObject *obwpath;
     wchar_t *wpath = NULL;
-    PyObject *oapath;
-    char *apath;
+    const char *apath;
     HANDLE hFile;
     time_t atimesec, mtimesec;
     long ausec, musec;
@@ -3571,11 +3595,11 @@ posix_utime(PyObject *self, PyObject *args)
            are also valid. */
         PyErr_Clear();
 
-        if (!PyArg_ParseTuple(args, "O&|O:utime",
-                        PyUnicode_FSConverter, &oapath, &arg))
+        if (!PyArg_ParseTuple(args, "y|O:utime", &apath, &arg))
+            return NULL;
+        if (win32_warn_bytes_api())
             return NULL;
 
-        apath = PyBytes_AsString(oapath);
         Py_BEGIN_ALLOW_THREADS
         hFile = CreateFileA(apath, FILE_WRITE_ATTRIBUTES, 0,
                             NULL, OPEN_EXISTING,
@@ -3583,10 +3607,8 @@ posix_utime(PyObject *self, PyObject *args)
         Py_END_ALLOW_THREADS
         if (hFile == INVALID_HANDLE_VALUE) {
             win32_error("utime", apath);
-            Py_DECREF(oapath);
             return NULL;
         }
-        Py_DECREF(oapath);
     }
 
     if (arg == Py_None) {
@@ -6516,7 +6538,8 @@ static PyObject *
 win_symlink(PyObject *self, PyObject *args, PyObject *kwargs)
 {
     static char *kwlist[] = {"src", "dest", "target_is_directory", NULL};
-    PyObject *src, *dest;
+    PyObject *osrc, *odest;
+    PyObject *usrc = NULL, *udest = NULL;
     wchar_t *wsrc, *wdest;
     int target_is_directory = 0;
     DWORD res;
@@ -6528,24 +6551,25 @@ win_symlink(PyObject *self, PyObject *args, PyObject *kwargs)
         return PyErr_Format(PyExc_NotImplementedError,
             "CreateSymbolicLinkW not found");
     }
-    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "OO|i:symlink",
-        kwlist, &src, &dest, &target_is_directory))
+    if (!PyArg_ParseTupleAndKeywords(
+            args, kwargs, "OO|i:symlink", kwlist,
+            &osrc, &odest, &target_is_directory))
         return NULL;
 
+    usrc = win32_decode_filename(osrc);
+    if (!usrc)
+        return NULL;
+    udest = win32_decode_filename(odest);
+    if (!udest)
+        goto error;
+
     if (win32_can_symlink == 0)
         return PyErr_Format(PyExc_OSError, "symbolic link privilege not held");
 
-    if (!convert_to_unicode(&src))
-        return NULL;
-    if (!convert_to_unicode(&dest)) {
-        Py_DECREF(src);
-        return NULL;
-    }
-
-    wsrc = PyUnicode_AsUnicode(src);
+    wsrc = PyUnicode_AsUnicode(usrc);
     if (wsrc == NULL)
         goto error;
-    wdest = PyUnicode_AsUnicode(dest);
+    wdest = PyUnicode_AsUnicode(udest);
     if (wsrc == NULL)
         goto error;
 
@@ -6563,17 +6587,17 @@ win_symlink(PyObject *self, PyObject *args, PyObject *kwargs)
     res = Py_CreateSymbolicLinkW(wdest, wsrc, target_is_directory);
     Py_END_ALLOW_THREADS
 
-    Py_DECREF(src);
-    Py_DECREF(dest);
+    Py_DECREF(usrc);
+    Py_DECREF(udest);
     if (!res)
-        return win32_error_object("symlink", src);
+        return win32_error_object("symlink", osrc);
 
     Py_INCREF(Py_None);
     return Py_None;
 
 error:
-    Py_DECREF(src);
-    Py_DECREF(dest);
+    Py_XDECREF(usrc);
+    Py_XDECREF(udest);
     return NULL;
 }
 #endif /* defined(HAVE_SYMLINK) && defined(MS_WINDOWS) */
@@ -6791,6 +6815,12 @@ posix_open(PyObject *self, PyObject *args)
                           PyUnicode_FSConverter, &ofile,
                           &flag, &mode))
         return NULL;
+#ifdef MS_WINDOWS
+    if (win32_warn_bytes_api()) {
+        Py_DECREF(ofile);
+        return NULL;
+    }
+#endif
     file = PyBytes_AsString(ofile);
     Py_BEGIN_ALLOW_THREADS
     fd = open(file, flag, mode);
@@ -9290,6 +9320,10 @@ normal:
                           PyUnicode_FSConverter, &ofilepath,
                           &operation))
         return NULL;
+    if (win32_warn_bytes_api()) {
+        Py_DECREF(ofilepath);
+        return NULL;
+    }
     filepath = PyBytes_AsString(ofilepath);
     Py_BEGIN_ALLOW_THREADS
     rc = ShellExecute((HWND)0, operation, filepath,