os.scandir does not work with filedescriptor

[albrycht]

Describe the bug
I'm using a code that is reading directory content in such a way:

os.chdir('/test-volume')
fd = os.open(''/test-volume'', flags=os.O_DIRECTORY)
content = list(os.scandir(fd))

This code should return content of /test-volume directory. I get:
[Errno 20] Not a directory in the fake filesystem: '/test-volume/df01d42e-1f05-41fa-9ef3-8463b03ff8f0'

It would be nice to add support for file descriptors or at least throw NotImplementedError when path is int.

How To Reproduce
Shown above.

Your environment

Linux-5.15.0-48-generic-x86_64-with-glibc2.35
Python 3.10.4 (main, Apr 28 2022, 10:58:00) [GCC 11.2.0]
pyfakefs 4.7.0

[mrbean-bremen]

Actually it should support this, at least the code suggests that. Can you please add a callstack? I also don't understand where it takes this uid from - is this a path in the fake filesystem?

[mrbean-bremen]

And can you please show a reproducible example? Your snippet does not look like real code, as it uses an invalid string notation.

[albrycht]

Here is an example that fails for me:

with Patcher() as patcher:
    patcher.fs.create_dir('/tmp/dir')
    patcher.fs.create_file('/tmp/dir/file1')
    patcher.fs.create_file('/tmp/dir/file2')
    patcher.fs.create_dir('/tmp/dir/subdir')

    os.chdir('/tmp/dir')
    fd = os.open('/tmp/dir', flags=os.O_DIRECTORY)
    children = [dir_entry.name for dir_entry in os.scandir(fd)]
    children.sort()
    assert children == ['file1', 'file2', 'subdir']

It throws error: NotADirectoryError: [Errno 20] Not a directory in the fake filesystem: '/tmp/dir/b8ec8d70-c3e6-4a14-94b9-f5c78f2c85c6' while executing os.scandir

Here is full stacktrace:

agent/tests/crawler/incremental_test.py:931 (CrawlerWorkerPerfTest.test_scandir_with_fd)
self = <crawler.incremental_test.CrawlerWorkerPerfTest testMethod=test_scandir_with_fd>

    def test_scandir_with_fd(self):
        with Patcher() as patcher:
            patcher.fs.create_dir('/tmp/dir')
            patcher.fs.create_file('/tmp/dir/file1')
            patcher.fs.create_file('/tmp/dir/file2')
            patcher.fs.create_dir('/tmp/dir/subdir')
    
            os.chdir('/tmp/dir')
            fd = os.open('/tmp/dir', flags=os.O_DIRECTORY)
>           children = [dir_entry.name for dir_entry in os.scandir(fd)]

agent/tests/crawler/incremental_test.py:941: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
../../.virtualenvs/sf/lib/python3.10/site-packages/pyfakefs/fake_filesystem.py:4995: in wrapped
    return f(*args, **kwargs)
../../.virtualenvs/sf/lib/python3.10/site-packages/pyfakefs/fake_filesystem.py:4334: in scandir
    return scandir(self.filesystem, path)
../../.virtualenvs/sf/lib/python3.10/site-packages/pyfakefs/fake_scandir.py:180: in scandir
    return ScanDirIter(filesystem, path)
../../.virtualenvs/sf/lib/python3.10/site-packages/pyfakefs/fake_scandir.py:136: in __init__
    entries = self.filesystem.confirmdir(self.abspath).entries
../../.virtualenvs/sf/lib/python3.10/site-packages/pyfakefs/fake_filesystem.py:3318: in confirmdir
    self.raise_os_error(errno.ENOTDIR, target_directory, 267)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <pyfakefs.fake_filesystem.FakeFilesystem object at 0x7f4f6b042380>
err_no = 20, filename = '/tmp/dir/b8ec8d70-c3e6-4a14-94b9-f5c78f2c85c6'
winerror = 267

    def raise_os_error(self, err_no: int,
                       filename: Optional[AnyString] = None,
                       winerror: Optional[int] = None) -> NoReturn:
        """Raises OSError.
        The error message is constructed from the given error code and shall
        start with the error string issued in the real system.
        Note: this is not true under Windows if winerror is given - in this
        case a localized message specific to winerror will be shown in the
        real file system.
    
        Args:
            err_no: A numeric error code from the C variable errno.
            filename: The name of the affected file, if any.
            winerror: Windows only - the specific Windows error code.
        """
        message = os.strerror(err_no) + ' in the fake filesystem'
        if (winerror is not None and sys.platform == 'win32' and
                self.is_windows_fs):
            raise OSError(err_no, message, filename, winerror)
>       raise OSError(err_no, message, filename)
E       NotADirectoryError: [Errno 20] Not a directory in the fake filesystem: '/tmp/dir/b8ec8d70-c3e6-4a14-94b9-f5c78f2c85c6'

[mrbean-bremen]

Thank you, I will try to reproduce this.

[mrbean-bremen]

Shall be fixed in master now. That was actually a bug I had accidentally introduced myself a couple of years ago, that never came up so far - good catch, thanks!