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Title: Pathlib resolve() on Mac prepends path
Type: behavior Stage: resolved
Components: macOS Versions: Python 3.7
Status: closed Resolution: not a bug
Dependencies: Superseder:
Assigned To: Nosy List: john.engelke, ned.deily, ronaldoussoren
Priority: normal Keywords:

Created on 2020-11-25 05:42 by john.engelke, last changed 2022-04-11 14:59 by admin. This issue is now closed.

Messages (3)
msg381792 - (view) Author: John Engelke (john.engelke) Date: 2020-11-25 05:42
On Mac OS X Catalina+, Pathlib's resolve() method prepends the System Integrity Protection (SIP) path to the front of the resolved Path, whether you like it or not. 

>>> from pathlib import Path
>>> host_path_str = "/home/somewhere/there/../nowhere"
>>> host_path = Path(host_path_str)
>>> host_path
>>> host_path.resolve()
>>> import platform
>>> platform.platform()
>>> import sys
>>> print (sys.version)
3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 16:52:21) 
[Clang 6.0 (clang-600.0.57)]

In my particular case, I'm just using this feature to resolve paths for an FTP host, so the path is contrived and doesn't actually exist locally. As one may guess, this breaks my FTP transfers by foisting a path on me that isn't on the server. 

I know there are other tix for Pathlib's erratic behavior across platforms which don't talk about this specific issue. I don't think it a behavior across platforms thing, anyway. Pathlib obviously isn't behaving nicely with SIP and Apple's Firmlink wormhole like directory traversal stuffs. Oy vey!
msg381795 - (view) Author: Ronald Oussoren (ronaldoussoren) * (Python committer) Date: 2020-11-25 08:30
I'm not sure if I understand what you're trying to do.

Is host_path_str a path on the local machine, or a path on the FTP server?

For the latter you probably want to use "PurePosixpath" instead of "Path", the latter is intended to be used for local paths and can access the filesystem.
msg381842 - (view) Author: John Engelke (john.engelke) Date: 2020-11-25 15:35
Thanks @ronaldoussoren. This bug report is flawed for a couple reasons, notwithstanding some assumptions I made incorrectly. (SIP actually makes "/home" a symlink so that resolved correctly.) So I am retracting it as-is because I can't edit the original report. 

The documentation for the behavior of resolve() is talking about using resolve() in the PurePath section. And, resolve() is removing "/../" when the path doesn't really exist locally. I'll open clearer tickets about those when I have a chance.
Date User Action Args
2022-04-11 14:59:38adminsetgithub: 86624
2020-11-25 15:35:56john.engelkesettitle: Pathlib resolve() on Mac Catalina prepends secret path -> Pathlib resolve() on Mac prepends path
2020-11-25 15:35:10john.engelkesetstatus: open -> closed
stage: resolved
2020-11-25 15:35:01john.engelkesetresolution: not a bug
messages: + msg381842
2020-11-25 08:30:11ronaldoussorensetmessages: + msg381795
2020-11-25 05:42:59john.engelkecreate