Patched os.symlink mishandles directory descriptors

[vector-of-bool]

Describe the bug
The os.symlink function accepts a dir_fd argument to specify the destination of the created symlink. The fakefs os.symlink is behaves incorrectly and uses the dir_fd to rewrite the src argument:

src = self._path_with_dir_fd(src, self.symlink, dir_fd)  # (wrong)
self.filesystem.create_symlink(dst, src, create_missing_dirs=False)

The src argument should be left verbatim as given. I am guessing that the code should have been written to resolve the dst argument instead:

dst = self._path_with_dir_fd(dst, self.symlink, dir_fd)
self.filesystem.create_symlink(dst, src, create_missing_dirs=False)

The doc comment is written to reflect the incorrect behavior.

How To Reproduce

def _test_symlink(base: Path):
    dir_fd = os.open(base, os.O_DIRECTORY)
    os.symlink("file.txt", "link.txt", dir_fd=dir_fd)
    assert os.readlink(base / "link.txt") == "file.txt"

def test_symlink_realfs(tmp_path: Path):
    _test_symlink(tmp_path)

def test_symlink_fakefs(fs):
    _test_symlink(Path("/tmp/"))

The os.symlink call above will succeed, but creates link.txt in the wrong location, leading to os.readlink generating a FileNotFoundError.

Your environment
Please run the following in the environment where the problem happened and
paste the output.

$ python -c "import platform; print(platform.platform())"
Linux-6.7.6-arch1-1-x86_64-with-glibc2.39
$ python -c "import sys; print('Python', sys.version)"
Python 3.11.7 (main, Jan 29 2024, 16:03:57) [GCC 13.2.1 20230801]
$ python -c "from pyfakefs import __version__; print('pyfakefs', __version__)"
pyfakefs 5.4.dev0
$ python -c "import pytest; print('pytest', pytest.__version__)"
pytest 7.2.0

[mrbean-bremen]

Thanks, that looks like an obvious bug, together with an incorrect or missing test.

[mrbean-bremen]

As usually: please test in main.
I will handle the other issue another day...

[vector-of-bool]

This appears to be fixed. Thanks again!