python · sobolevn · Jul 23, 2025 · Jul 21, 2025 · Jul 22, 2025 · Jul 22, 2025
diff --git a/Lib/genericpath.py b/Lib/genericpath.py
@@ -81,28 +81,28 @@ def isdevdrive(path):
     return False
 
 
-def getsize(filename):
+def getsize(filename, /):
     """Return the size of a file, reported by os.stat()."""
     return os.stat(filename).st_size
 
 
-def getmtime(filename):
+def getmtime(filename, /):
     """Return the last modification time of a file, reported by os.stat()."""
     return os.stat(filename).st_mtime
 
 
-def getatime(filename):
+def getatime(filename, /):
     """Return the last access time of a file, reported by os.stat()."""
     return os.stat(filename).st_atime
 
 
-def getctime(filename):
+def getctime(filename, /):
     """Return the metadata change time of a file, reported by os.stat()."""
     return os.stat(filename).st_ctime
 
 
 # Return the longest prefix of all list elements.
-def commonprefix(m):
+def commonprefix(m, /):
     "Given a list of pathnames, returns the longest common leading component"
     if not m: return ''
     # Some people pass in a list of pathname parts to operate in an OS-agnostic
@@ -120,14 +120,14 @@ def commonprefix(m):
 
 # Are two stat buffers (obtained from stat, fstat or lstat)
 # describing the same file?
-def samestat(s1, s2):
+def samestat(s1, s2, /):
     """Test whether two stat buffers reference the same file"""
     return (s1.st_ino == s2.st_ino and
             s1.st_dev == s2.st_dev)
 
 
 # Are two filenames really pointing to the same file?
-def samefile(f1, f2):
+def samefile(f1, f2, /):
     """Test whether two pathnames reference the same actual file or directory
 
     This is determined by the device number and i-node number and

diff --git a/Lib/ntpath.py b/Lib/ntpath.py
@@ -47,7 +47,7 @@ def _get_bothseps(path):
         LOCALE_NAME_INVARIANT as _LOCALE_NAME_INVARIANT,
         LCMAP_LOWERCASE as _LCMAP_LOWERCASE)
 
-    def normcase(s):
+    def normcase(s, /):
         """Normalize case of pathname.
 
         Makes all characters lowercase and all slashes into backslashes.
@@ -66,7 +66,7 @@ def normcase(s):
                                   _LCMAP_LOWERCASE,
                                   s.replace('/', '\\'))
 except ImportError:
-    def normcase(s):
+    def normcase(s, /):
         """Normalize case of pathname.
 
         Makes all characters lowercase and all slashes into backslashes.
@@ -77,7 +77,7 @@ def normcase(s):
         return s.replace('/', '\\').lower()
 
 
-def isabs(s):
+def isabs(s, /):
     """Test whether a path is absolute"""
     s = os.fspath(s)
     if isinstance(s, bytes):
@@ -96,7 +96,7 @@ def isabs(s):
 
 
 # Join two (or more) paths.
-def join(path, *paths):
+def join(path, /, *paths):
     path = os.fspath(path)
     if isinstance(path, bytes):
         sep = b'\\'
@@ -143,7 +143,7 @@ def join(path, *paths):
 # Split a path in a drive specification (a drive letter followed by a
 # colon) and the path specification.
 # It is always true that drivespec + pathspec == p
-def splitdrive(p):
+def splitdrive(p, /):
     """Split a pathname into drive/UNC sharepoint and relative path specifiers.
     Returns a 2-tuple (drive_or_unc, path); either part may be empty.
 
@@ -169,7 +169,7 @@ def splitdrive(p):
 try:
     from nt import _path_splitroot_ex as splitroot
 except ImportError:
-    def splitroot(p):
+    def splitroot(p, /):
         """Split a pathname into drive, root and tail.
 
         The tail contains anything after the root."""
@@ -219,7 +219,7 @@ def splitroot(p):
 # join(head, tail) == p holds.
 # The resulting head won't end in '/' unless it is the root.
 
-def split(p):
+def split(p, /):
     """Split a pathname.
 
     Return tuple (head, tail) where tail is everything after the final slash.
@@ -240,7 +240,7 @@ def split(p):
 # pathname component; the root is everything before that.
 # It is always true that root + ext == p.
 
-def splitext(p):
+def splitext(p, /):
     p = os.fspath(p)
     if isinstance(p, bytes):
         return genericpath._splitext(p, b'\\', b'/', b'.')
@@ -251,14 +251,14 @@ def splitext(p):
 
 # Return the tail (basename) part of a path.
 
-def basename(p):
+def basename(p, /):
     """Returns the final component of a pathname"""
     return split(p)[1]
 
 
 # Return the head (dirname) part of a path.
 
-def dirname(p):
+def dirname(p, /):
     """Returns the directory component of a pathname"""
     return split(p)[0]
 
@@ -601,7 +601,7 @@ def abspath(path):
     from nt import _findfirstfile, _getfinalpathname, readlink as _nt_readlink
 except ImportError:
     # realpath is a no-op on systems without _getfinalpathname support.
-    def realpath(path, *, strict=False):
+    def realpath(path, /, *, strict=False):
         return abspath(path)
 else:
     def _readlink_deep(path, ignored_error=OSError):
@@ -702,7 +702,7 @@ def _getfinalpathname_nonstrict(path, ignored_error=OSError):
                 tail = join(name, tail) if tail else name
         return tail
 
-    def realpath(path, *, strict=False):
+    def realpath(path, /, *, strict=False):
         path = normpath(path)
         if isinstance(path, bytes):
             prefix = b'\\\\?\\'

diff --git a/Lib/posixpath.py b/Lib/posixpath.py
@@ -50,15 +50,15 @@ def _get_sep(path):
 # normalizations (such as optimizing '../' away) are not allowed
 # (another function should be defined to do that).
 
-def normcase(s):
+def normcase(s, /):
     """Normalize case of pathname.  Has no effect under Posix"""
     return os.fspath(s)
 
 
 # Return whether a path is absolute.
 # Trivial in Posix, harder on the Mac or MS-DOS.
 
-def isabs(s):
+def isabs(s, /):
     """Test whether a path is absolute"""
     s = os.fspath(s)
     sep = _get_sep(s)
@@ -69,7 +69,7 @@ def isabs(s):
 # Ignore the previous parts if a part is absolute.
 # Insert a '/' unless the first part is empty or already ends in '/'.
 
-def join(a, *p):
+def join(a, /, *p):
     """Join two or more pathname components, inserting '/' as needed.
     If any component is an absolute path, all previous path components
     will be discarded.  An empty last part will result in a path that
@@ -97,7 +97,7 @@ def join(a, *p):
 # '/' in the path, head  will be empty.
 # Trailing '/'es are stripped from head unless it is the root.
 
-def split(p):
+def split(p, /):
     """Split a pathname.  Returns tuple "(head, tail)" where "tail" is
     everything after the final slash.  Either part may be empty."""
     p = os.fspath(p)
@@ -114,7 +114,7 @@ def split(p):
 # pathname component; the root is everything before that.
 # It is always true that root + ext == p.
 
-def splitext(p):
+def splitext(p, /):
     p = os.fspath(p)
     if isinstance(p, bytes):
         sep = b'/'
@@ -128,7 +128,7 @@ def splitext(p):
 # Split a pathname into a drive specification and the rest of the
 # path.  Useful on DOS/Windows/NT; on Unix, the drive is always empty.
 
-def splitdrive(p):
+def splitdrive(p, /):
     """Split a pathname into drive and path. On Posix, drive is always
     empty."""
     p = os.fspath(p)
@@ -138,7 +138,7 @@ def splitdrive(p):
 try:
     from posix import _path_splitroot_ex as splitroot
 except ImportError:
-    def splitroot(p):
+    def splitroot(p, /):
         """Split a pathname into drive, root and tail.
 
         The tail contains anything after the root."""
@@ -163,7 +163,7 @@ def splitroot(p):
 
 # Return the tail (basename) part of a path, same as split(path)[1].
 
-def basename(p):
+def basename(p, /):
     """Returns the final component of a pathname"""
     p = os.fspath(p)
     sep = _get_sep(p)
@@ -173,7 +173,7 @@ def basename(p):
 
 # Return the head (dirname) part of a path, same as split(path)[0].
 
-def dirname(p):
+def dirname(p, /):
     """Returns the directory component of a pathname"""
     p = os.fspath(p)
     sep = _get_sep(p)
@@ -388,7 +388,7 @@ def abspath(path):
 # Return a canonical path (i.e. the absolute location of a file on the
 # filesystem).
 
-def realpath(filename, *, strict=False):
+def realpath(filename, /, *, strict=False):
     """Return the canonical path of the specified filename, eliminating any
 symbolic links encountered in the path."""
     filename = os.fspath(filename)