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gh-158998: Fix os.statx() ignoring follow_symlinks=False #158999

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gh-158998: Fix os.statx() ignoring follow_symlinks=False #158999

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771e323
gh-158998: Fix os.statx() ignoring follow_symlinks=False
jjhelmus Oct 7, 2026
64bccc9
test statx follow_symlinks behavior
jjhelmus Oct 8, 2026
afe07b8
📜🤖 Added by blurb_it.
blurb-it[bot] Oct 8, 2026
c328864
directly call statx for a broken symlink
jjhelmus Oct 8, 2026
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28 changes: 25 additions & 3 deletions Lib/test/test_os/test_os.py
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Original file line number Diff line number Diff line change
Expand Up @@ -752,13 +752,13 @@ def test_stat_result_pickle(self):
unpickled = pickle.loads(p)
self.assertEqual(result, unpickled)

def check_statx_attributes(self, filename):
def check_statx_attributes(self, filename, follow_symlinks=True):
maximal_mask = 0
for name in dir(os):
if name.startswith('STATX_'):
maximal_mask |= getattr(os, name)
result = os.statx(filename, maximal_mask)
stat_result = os.stat(filename)
result = os.statx(filename, maximal_mask, follow_symlinks=follow_symlinks)
stat_result = os.stat(filename, follow_symlinks=follow_symlinks)

time_attributes = ('stx_atime', 'stx_btime', 'stx_ctime', 'stx_mtime')
# gh-83714: stx_btime can be None on tmpfs even if STATX_BTIME mask
Expand Down Expand Up @@ -873,6 +873,28 @@ def getmask(name):
def test_statx_attributes(self):
self.check_statx_attributes(self.fname)

@unittest.skipUnless(hasattr(os, 'statx'), 'test needs os.statx()')
@os_helper.skip_unless_symlink
def test_statx_attributes_symlink(self):
link = self.fname + '-link'
os.symlink(os.path.basename(self.fname), link)
self.addCleanup(os_helper.unlink, link)

with self.subTest(broken=False, follow_symlinks=True):
self.check_statx_attributes(link, follow_symlinks=True)

with self.subTest(broken=False, follow_symlinks=False):
self.check_statx_attributes(link, follow_symlinks=False)

# break the symlink
os.unlink(self.fname)
with self.subTest(broken=True, follow_symlinks=True):
with self.assertRaises(FileNotFoundError):

@jbosboom jbosboom Oct 8, 2026

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check_statx_attributes only accidentally checks that os.statx raises in this case (because os.statx is called before os.stat). I think it's sufficient and clearer to call os.statx directly here.

@jbosboom jbosboom Oct 8, 2026

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I mean: replace self.check_statx_attributes -> os.statx on the line just after the lines shown in the comment. (Sorry, not used to GitHub's review/comment interface.)

@jjhelmus jjhelmus Oct 8, 2026

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Agreed that calling statx here is clearer. I've updated the test.

os.statx(link, os.STATX_BASIC_STATS, follow_symlinks=True)

with self.subTest(broken=True, follow_symlinks=False):
self.check_statx_attributes(link, follow_symlinks=False)

@unittest.skipUnless(hasattr(os, 'statx'), 'test needs os.statx()')
def test_statx_attributes_bytes(self):
try:
Expand Down
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Library/2026-10-08-21-02-38.gh-issue-158998.DZYJI7.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Fix :func:`os.statx` ignoring the *follow_symlinks* argument.
3 changes: 3 additions & 0 deletions Modules/posixmodule.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3669,6 +3669,9 @@ os_statx_impl(PyObject *module, path_t *path, unsigned int mask, int flags,
"use dir_fd kwarg instead of AT_EMPTY_PATH flag");
return NULL;
}
if (!follow_symlinks) {
flags |= AT_SYMLINK_NOFOLLOW;
}

/* Future bits may refer to members beyond the current size of struct
statx, so we need to mask them off to prevent memory corruption. */
Expand Down
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