Path_u doesn't support file protocol on Windows

[RoryDungan]

🐛 Bug report

I have an argument of type Path_u. When I pass a file protocol URL to a file that I know does exist I get an error saying "File does not exist". The issue only seems to happen on Windows.

To reproduce

Example code:

from jsonargparse import ArgumentParser
from jsonargparse.typing import path_type

parser = ArgumentParser()
parser.add_argument("--path", type=path_type("u"))

args = parser.parse_args()

print(f"path: {args.path}")

To run:

python example.py --path "file:///C:/Users/r_dungan/dev/test/file_protocol_test/example.py"

This resulted in the following output:

usage: example.py [-h] [--path PATH]
example.py: error: Configuration check failed :: Parser key "path": Not of type Path_u. File does not exist: /C:/Users/r_dungan/dev/test/file_protocol_test/example.py

This seems to be a result of the logic at util.py:408 that replaces file:/// with / before checking if the file exists. This works fine on Unix-like platforms but on windows it results in an extra "/" at the beginning of the path before the drive letter, which makes it invalid.

Expected behavior

The path should be picked up by JsonArgParse with no errors. On Linux, this happens as long as the file exists:

$ python3 example.py --path file:///mnt/c/Users/r_dungan/dev/test/file_protocol_test/example.py
path: file:///mnt/c/Users/r_dungan/dev/test/file_protocol_test/example.py

Environment

• jsonargparse version: 4.10.2
• Python version: 3.10.5, 3.9.10
• How jsonargparse was installed: pip install jsonargparse, poetry install jsonargparse
• OS: Windows 10 21H2

[mauvilsa]

@RoryDungan would you like to create a pull request with the fix?

[mauvilsa]

Fixed in af9e6df.