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gh-117705: Add follow_symlinks to os.path.exists() #117729

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7 changes: 5 additions & 2 deletions Doc/library/os.path.rst
Original file line number Diff line number Diff line change
Expand Up @@ -127,10 +127,11 @@ the :mod:`glob` module.)
Accepts a :term:`path-like object`.


.. function:: exists(path)
.. function:: exists(path, *, follow_symlinks=True)

Return ``True`` if *path* refers to an existing path or an open
file descriptor. Returns ``False`` for broken symbolic links. On
file descriptor. Returns ``False`` for broken symbolic links if
*follow_symlinks* is set, otherwise ``True``. On
some platforms, this function may return ``False`` if permission is
not granted to execute :func:`os.stat` on the requested file, even
if the *path* physically exists.
Expand All @@ -142,6 +143,8 @@ the :mod:`glob` module.)
.. versionchanged:: 3.6
Accepts a :term:`path-like object`.

.. versionchanged:: 3.13
Added the *follow_symlinks* parameter.

.. function:: lexists(path)

Expand Down
7 changes: 4 additions & 3 deletions Lib/genericpath.py
Original file line number Diff line number Diff line change
Expand Up @@ -13,10 +13,11 @@

# Does a path exist?
# This is false for dangling symbolic links on systems that support them.
def exists(path):
"""Test whether a path exists. Returns False for broken symbolic links"""
def exists(path, *, follow_symlinks=True):
"""Test whether a path exists. Returns False for broken symbolic links
if follow_symlinks is set, otherwise True"""
try:
os.stat(path)
os.stat(path, follow_symlinks=follow_symlinks)
except (OSError, ValueError):
return False
return True
Expand Down
1 change: 1 addition & 0 deletions Lib/ntpath.py
Original file line number Diff line number Diff line change
Expand Up @@ -899,6 +899,7 @@ def commonpath(paths):
from nt import _path_isfile as isfile
from nt import _path_islink as islink
from nt import _path_exists as exists
from nt import _path_lexists as lexists
except ImportError:
# Use genericpath.* as imported above
pass
Expand Down
41 changes: 26 additions & 15 deletions Lib/test/test_genericpath.py
Original file line number Diff line number Diff line change
Expand Up @@ -128,31 +128,42 @@ def test_filetime(self):
)

def test_exists(self):
def check_exists(filename, expected):
bfilename = os.fsencode(filename)
self.assertIs(self.pathmodule.exists(filename), expected)
self.assertIs(self.pathmodule.exists(bfilename), expected)
self.assertIs(self.pathmodule.exists(filename, follow_symlinks=True),
expected)
self.assertIs(self.pathmodule.exists(bfilename, follow_symlinks=True),
expected)

def check_lexists(filename, expected):
bfilename = os.fsencode(filename)
self.assertIs(self.pathmodule.lexists(filename), expected)
self.assertIs(self.pathmodule.lexists(bfilename), expected)
self.assertIs(self.pathmodule.exists(filename, follow_symlinks=False),
expected)
self.assertIs(self.pathmodule.exists(bfilename, follow_symlinks=False),
expected)

filename = os_helper.TESTFN
bfilename = os.fsencode(filename)
self.addCleanup(os_helper.unlink, filename)

self.assertIs(self.pathmodule.exists(filename), False)
self.assertIs(self.pathmodule.exists(bfilename), False)
check_exists(filename, False)
check_lexists(filename, False)

create_file(filename)

self.assertIs(self.pathmodule.exists(filename), True)
self.assertIs(self.pathmodule.exists(bfilename), True)

check_exists(filename, True)
self.assertIs(self.pathmodule.exists(filename + '\udfff'), False)
self.assertIs(self.pathmodule.exists(bfilename + b'\xff'), False)
self.assertIs(self.pathmodule.exists(filename + '\x00'), False)
self.assertIs(self.pathmodule.exists(bfilename + b'\x00'), False)

if self.pathmodule is not genericpath:
self.assertIs(self.pathmodule.lexists(filename), True)
self.assertIs(self.pathmodule.lexists(bfilename), True)
check_exists(filename + '\x00', False)

self.assertIs(self.pathmodule.lexists(filename + '\udfff'), False)
self.assertIs(self.pathmodule.lexists(bfilename + b'\xff'), False)
self.assertIs(self.pathmodule.lexists(filename + '\x00'), False)
self.assertIs(self.pathmodule.lexists(bfilename + b'\x00'), False)
check_lexists(filename, True)
self.assertIs(self.pathmodule.lexists(filename + '\udfff'), False)
self.assertIs(self.pathmodule.lexists(bfilename + b'\xff'), False)
check_lexists(filename + '\x00', False)

@unittest.skipUnless(hasattr(os, "pipe"), "requires os.pipe()")
@unittest.skipIf(is_emscripten, "Emscripten pipe fds have no stat")
Expand Down
2 changes: 2 additions & 0 deletions Lib/test/test_ntpath.py
Original file line number Diff line number Diff line change
Expand Up @@ -1115,6 +1115,8 @@ def test_fast_paths_in_use(self):
self.assertFalse(inspect.isfunction(os.path.islink))
self.assertTrue(os.path.exists is nt._path_exists)
self.assertFalse(inspect.isfunction(os.path.exists))
self.assertTrue(os.path.lexists is nt._path_lexists)
self.assertFalse(inspect.isfunction(os.path.lexists))

@unittest.skipIf(os.name != 'nt', "Dev Drives only exist on Win32")
def test_isdevdrive(self):
Expand Down
Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Added the *follow_symlinks* parameter to :func:`os.path.exists`.
96 changes: 90 additions & 6 deletions Modules/clinic/posixmodule.c.h

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