Fix union type conversion to path

Author: George-Ogden

git/refs/log.py

@@ -168,7 +168,7 @@ def __init__(self, filepath: Union[PathLike, None] = None) -> None:
         """Initialize this instance with an optional filepath, from which we will
         initialize our data. The path is also used to write changes back using the
         :meth:`write` method."""
-        self._path = os.fspath(filepath)
+        self._path = None if filepath is None else os.fspath(filepath)
         if filepath is not None:
             self._read_from_file()
         # END handle filepath