Sidestep os.path.relpath() Windows bug

[glenn-jocher]

os.path.relpath() seems to have a major bug on Windows caused by Windows own horrible path handling. This fix attempts to sidestep the issue.

File "C:\Users\mkokg/.cache\torch\hub\ultralytics_yolov5_master\export.py", line 64, in
ROOT = Path(os.path.relpath(ROOT, Path.cwd())) # relative
File "C:\Users\mkokg\AppData\Local\Programs\Python\Python310\lib\ntpath.py", line 718, in relpath
raise ValueError("path is on mount %r, start on mount %r" % (
ValueError: path is on mount 'C:', start on mount 'D:'

More info at https://bugs.python.org/issue7195

Test script:

import torch

model = torch.hub.load('ultralytics/yolov5:fix/relpath', 'yolov5s', force_reload=True)

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Improved cross-platform path handling in YOLOv5's export and model scripts.

📊 Key Changes

• Added import os and import platform to check the operating system type.
• Conditionally set the ROOT path to be relative unless running on Windows.

🎯 Purpose & Impact

• Purpose: To ensure proper path handling across different operating systems, addressing an issue where setting a relative ROOT path may cause errors on Windows.
• Impact: Users on non-Windows systems will benefit from cleaner path management, while Windows users will have reduced risk of encountering path-related errors. This change promotes cross-platform compatibility, making YOLOv5 more robust and user-friendly. 🖥️🚀