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

[Serhiy Storchaka]

16.05.19 17:05, Antoine Pitrou пише:
> On Thu, 16 May 2019 16:04:36 +0300
> Serhiy Storchaka <storchaka at gmail.com>
> wrote:
>> 16.05.19 14:33, Antoine Pitrou пише:
>>> On Thu, 16 May 2019 13:05:48 +0300
>>> Serhiy Storchaka <storchaka at gmail.com>
>>> wrote:
>>>> 16.05.19 11:28, Barry Scott пише:
>>>>> To replace one symlink with another atomically is possible by using rename() or renameat()
>>>>> something like:
>>>>>
>>>>> 	os.symlink( src, tmp_symlink )
>>>>> 	os.rename( tmp_symlink, dst )
>>>>
>>>> Somebody can replace tmp_symlink between os.symlink() and os.rename().
>>>
>>> Not if tmp_symlink is created in a directory with strict permissions, I
>>> guess.
>>
>> But in such case we do not need complex games with a temporary symlink.
>> Just use os.symlink() and os.unlink() if needed.
> 
> I was talking about the *tmp_symlink*, not *dst*.

They both should be on the same file system. The simplest way to achieve 
this is to create tmp_symlink in the same directory as dst.