[Python-ideas] shutil.symlink to allow non-race replacement of existing link targets

[Serhiy Storchaka]

13.05.19 12:38, Tom Hale пише:
> As suggested by Toshio Kuratomi at https://bugs.python.org/issue36656, I 
> am raising this here for inclusion in the shutil module.
> 
> Mimicking POSIX, os.symlink() will raise FileExistsError if the link 
> name to be created already exists.
> 
> A common use case is overwriting an existing file (often a symlink) with 
> a symlink. Naively, one would delete the file named link_name file if it 
> exists, then call symlink(). This "solution" is already 3 lines of code, 
> and without exception handling it introduces the race condition of a 
> file named link_name being created between unlink and symlink.
> 
> Depending on the functionality required, I suggest:
> 
> * os.symlink() - the new link name is expected to NOT exist
> * shutil.symlink() - the new symlink replaces an existing file

Sorry, but I do not understand what problem do you try to solve. If 
somebody can create a file named link_name between unlink and symlink, 
he can also remove and create a file named link_name after symlink.