| from __future__ import annotations | |
| import os | |
| import stat | |
| def raise_on_exist_ro_file(filename: str) -> None: | |
| try: | |
| file_stat = os.stat(filename) # use stat to do exists + can write to check without race condition | |
| except OSError: | |
| return None # swallow does not exist or other errors | |
| if file_stat.st_mtime != 0: # if os.stat returns but modification is zero that's an invalid os.stat - ignore it | |
| if not (file_stat.st_mode & stat.S_IWUSR): | |
| raise PermissionError(f"Permission denied: {filename!r}") | |
| __all__ = [ | |
| "raise_on_exist_ro_file", | |
| ] | |