Closed
Description
Bug report
the pathlib.Path.parents[-1] didn't receive the self._parts
example:
[#6#wangx@manjaro-5800:~] $ python
Python 3.10.4 (main, Mar 23 2022, 23:05:40) [GCC 11.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from pathlib import Path
>>> Path("/home/wangx").parents[-1]
PosixPath('/')
>>> Path("/home/wangx").parents[-1] == Path("/")
False
>>> Path("/home/wangx").parents[1] == Path("/")
True
>>> Path("/home/wangx").parents[1]
PosixPath('/')
>>>
source code in pathlib.py:
422 class _PathParents(Sequence):
423 """This object provides sequence-like access to the logical ancestors
424 of a path. Don't try to construct it yourself."""
425 __slots__ = ('_pathcls', '_drv', '_root', '_parts')
426
427 def __init__(self, path):
428 # We don't store the instance to avoid reference cycles
429 self._pathcls = type(path)
430 self._drv = path._drv
431 self._root = path._root
432 self._parts = path._parts
433
434 def __len__(self):
435 if self._drv or self._root:
436 return len(self._parts) - 1
437 else:
438 return len(self._parts)
439
440 def __getitem__(self, idx):
441 if isinstance(idx, slice):
442 return tuple(self[i] for i in range(*idx.indices(len(self))))
443
444 if idx >= len(self) or idx < -len(self):
445 raise IndexError(idx)
446 return self._pathcls._from_parsed_parts(self._drv, self._root,
447 self._parts[:-idx - 1])
when the idx is -1, -idx - 1 = 0. so the self._parts[: -idx -1 ] is empty. hence then the parents[-1] != parents[2] because the _parts is different.
Your environment
- CPython versions tested on: 3.10.4 and 3.12.0a0(main branch)
- Operating system and architecture:
Manjaro Linux 21.2.6 Linux manjaro-5800 5.4.195-1-MANJARO #1 SMP PREEMPT Wed May 18 09:23:31 UTC 2022 x86_64 GNU/Linux