(Windows) passing a file path collects the whole suite, on a network drive where st_ino is 0

[giampaolo]

Hi,
when developing psutil on Windows, I do it by mapping X: to a sshfs share, so from Linux I can SSH into Windows and run tests there. Problem: pytest ignores the file I pass and collects everything:

$ python -m pytest tests/test_memleaks.py --collect-only -o addopts=""
platform win32 -- Python 3.14.6, pytest-9.1.1, pluggy-1.6.0
rootdir: X:\svn\psutil
collected 961 items

That file ( tests/test_memleaks.py ) has 130 tests, while 961 is the whole repo. Using absolute paths does the same.

I think the culprit is samefile_nofollow(), which Session.collect() falls back to on Windows when two paths don't compare equal. On this drive every file has st_ino == 0, so it says any two files are the same one:

$ python -c "
import os
a = os.stat('tests/test_memleaks.py')
b = os.stat('tests/test_process.py')
print(a.st_dev, a.st_ino)
print(b.st_dev, b.st_ino)
print(os.path.samestat(a, b))
"
3816903231 0
3816903231 0
True

So every node matches, nothing gets pruned, and I get the whole tree. The name parts still work, which fits: :: filtering happens after the path level.

$ python -m pytest "tests/test_memleaks.py::TestProcess" --collect-only -q
tests/test_windows.py::TestProcess::test_wait
175 tests collected

That's TestProcess from every file, not the one I asked for.

Maybe the fallback should just bail out when either st_ino is 0, since it can't tell anything apart at that point:

 def samefile_nofollow(p1: Path, p2: Path) -> bool:
-    return os.path.samestat(p1.lstat(), p2.lstat())
+    s1, s2 = p1.lstat(), p2.lstat()
+    if not s1.st_ino or not s2.st_ino:
+        return False
+    return os.path.samestat(s1, s2)

Returning False falls back to plain path comparison, which is what the other platforms do anyway. The short-path case this was added for (#11895) is on local NTFS, so it keeps working.

-m and -k work fine. Anything taking a path (--ignore, --deselect, plain args) doesn't.

[RonnyPfannschmidt]

🙀 inode zero is allowed on windows - will fix 😨