Result.serialize() path handling is broken for windows paths and some other cases

[aucampia]

I have been trying to figure out what is happening with these xfails:

rdflib/test/test_sparql/test_result.py

Lines 282 to 306 in 1d5f3e7

	if sys.platform == "win32":
	xfails[("csv", DestinationType.STR_PATH, "utf-8")] = pytest.mark.xfail(
	raises=FileNotFoundError,
	reason="string path handling does not work on windows",
	)
	xfails[("csv", DestinationType.STR_PATH, "utf-16")] = pytest.mark.xfail(
	raises=FileNotFoundError,
	reason="string path handling does not work on windows",
	)
	xfails[("json", DestinationType.STR_PATH, "utf-8")] = pytest.mark.xfail(
	raises=FileNotFoundError,
	reason="string path handling does not work on windows",
	)
	xfails[("json", DestinationType.STR_PATH, "utf-16")] = pytest.mark.xfail(
	raises=FileNotFoundError,
	reason="string path handling does not work on windows",
	)
	xfails[("xml", DestinationType.STR_PATH, "utf-8")] = pytest.mark.xfail(
	raises=FileNotFoundError,
	reason="string path handling does not work on windows",
	)
	xfails[("xml", DestinationType.STR_PATH, "utf-16")] = pytest.mark.xfail(
	raises=FileNotFoundError,
	reason="string path handling does not work on windows",
	)

The problem is with the approach to path handling:

rdflib/rdflib/query.py

Lines 268 to 279 in 1d5f3e7

	location = cast(str, destination)
	scheme, netloc, path, params, query, fragment = urlparse(location)
	if netloc != "":
	print(
	"WARNING: not saving as location" + "is not a local file reference"
	)
	return None
	fd, name = tempfile.mkstemp()
	stream = os.fdopen(fd, "wb")
	serializer.serialize(stream, encoding=encoding, **args)
	stream.close()
	shutil.move(name, path)

The problem with this approach is that file URIs and OS paths are quite different, for one, with windows OS paths, e.g. C:\Users\runneradmin\AppData\Local\Temp\pytest-of-unknown\pytest-0\test_select_result_serialize_p6\file-DestinationType.STR_PATH, the drive letter gets interpreted as the URL scheme:

$ python3 -c 'from urllib.parse import urlparse; print(urlparse(r"C:\Users\runneradmin\AppData\Local\Temp\pytest-of-unknown\pytest-0\test_select_result_serialize_p6\file-DestinationType.STR_PATH"))'
ParseResult(scheme='c', netloc='', path='\\Users\\runneradmin\\AppData\\Local\\Temp\\pytest-of-unknown\\pytest-0\\test_select_result_serialize_p6\\file-DestinationType.STR_PATH', params='', query='', fragment='')

Furthermore, URIs support percent encoding, while OS paths do not.

Here is an example of things going wrong (from here)

  ------------------------------ Captured log call ------------------------------
  2022-07-30T12:11:21.926 ERROR    root         test_result.py:317:test_select_result_serialize_parse destination = C:\Users\runneradmin\AppData\Local\Temp\pytest-of-unknown\pytest-0\test_select_result_serialize_p6\file-DestinationType.STR_PATH
  2022-07-30T12:11:21.926 ERROR    root         test_result.py:318:test_select_result_serialize_parse format = csv
  2022-07-30T12:11:21.926 ERROR    root         test_result.py:319:test_select_result_serialize_parse encoding = utf-16
  ___________ test_select_result_serialize_parse[csv-STR_PATH-utf-8] ____________
  Traceback (most recent call last):
    File "C:\hostedtoolcache\windows\Python\3.7.9\x64\lib\shutil.py", line 566, in move
      os.rename(src, real_dst)
  FileNotFoundError: [WinError 3] The system cannot find the path specified: 'C:\\Users\\RUNNER~1\\AppData\\Local\\Temp\\tmpgk0vyq6q' -> '\\Users\\runneradmin\\AppData\\Local\\Temp\\pytest-of-unknown\\pytest-0\\test_select_result_serialize_p7\\file-DestinationType.STR_PATH'
  
  During handling of the above exception, another exception occurred:
  
  Traceback (most recent call last):
    File "D:\a\rdflib\rdflib\test\test_sparql\test_result.py", line 323, in test_select_result_serialize_parse
      encoding=encoding,
    File "D:\a\rdflib\rdflib\rdflib\query.py", line 283, in serialize
      shutil.move(name, path)
    File "C:\hostedtoolcache\windows\Python\3.7.9\x64\lib\shutil.py", line 580, in move
      copy_function(src, real_dst)
    File "C:\hostedtoolcache\windows\Python\3.7.9\x64\lib\shutil.py", line 266, in copy2
      copyfile(src, dst, follow_symlinks=follow_symlinks)
    File "C:\hostedtoolcache\windows\Python\3.7.9\x64\lib\shutil.py", line 121, in copyfile
      with open(dst, 'wb') as fdst:
  FileNotFoundError: [Errno 2] No such file or directory: '\\Users\\runneradmin\\AppData\\Local\\Temp\\pytest-of-unknown\\pytest-0\\test_select_result_serialize_p7\\file-DestinationType.STR_PATH'

I think the best we can do to fix the path handling is to do the same as what happens in Graph.serialize

rdflib/rdflib/graph.py

Lines 1204 to 1218 in 1d5f3e7

	if isinstance(destination, pathlib.PurePath):
	location = str(destination)
	else:
	location = cast(str, destination)
	scheme, netloc, path, params, _query, fragment = urlparse(location)
	if netloc != "":
	raise ValueError(
	f"destination {destination} is not a local file reference"
	)
	fd, name = tempfile.mkstemp()
	stream = os.fdopen(fd, "wb")
	serializer.serialize(stream, base=base, encoding=encoding, **args)
	stream.close()
	dest = url2pathname(path) if scheme == "file" else location
	shutil.move(name, dest)

This will fill relative path handling in some cases also, however it will break relative URI handling.