There is a problem with escape characters in the path passed in by pathlib.Path.mkdir()

[vincentfung]

BPO	46916
Nosy	@pfmoore, @tjguk, @zware, @eryksun, @zooba

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2022-03-04.10:56:33.339>
created_at = <Date 2022-03-03.22:17:38.626>
labels = ['type-bug', 'invalid', '3.10', 'OS-windows']
title = 'There is a problem with escape characters in the path passed in by pathlib.Path.mkdir()'
updated_at = <Date 2022-03-04.13:21:07.701>
user = 'https://bugs.python.org/vincentfung'

bugs.python.org fields:

activity = <Date 2022-03-04.13:21:07.701>
actor = 'vincent.fung'
assignee = 'none'
closed = True
closed_date = <Date 2022-03-04.10:56:33.339>
closer = 'vincent.fung'
components = ['Windows']
creation = <Date 2022-03-03.22:17:38.626>
creator = 'vincent.fung'
dependencies = []
files = []
hgrepos = []
issue_num = 46916
keywords = []
message_count = 7.0
messages = ['414483', '414487', '414503', '414504', '414514', '414517', '414524']
nosy_count = 6.0
nosy_names = ['paul.moore', 'tim.golden', 'zach.ware', 'eryksun', 'steve.dower', 'vincent.fung']
pr_nums = []
priority = 'normal'
resolution = 'not a bug'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue46916'
versions = ['Python 3.10']

[vincentfung]

This problem occurs when the directory starts with 't', but works with os.makedirs(e) or macOS.

>>> e = Path(r'F:\ceven\test2')
>>> e.mkdir()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Program Files\Python310\lib\pathlib.py", line 1173, in mkdir
    self._accessor.mkdir(self, mode)
FileNotFoundError: [WinError 3] The system cannot find the path specified: 'F:\\ceven\\test2'
>>> os.makedirs(e)

[vincentfung]

This problem occurs when the directory starts with 't', but works with os.makedirs(e) or macOS.

>>> e = Path(r'F:\ceven\test2')
>>> e.mkdir()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Program Files\Python310\lib\pathlib.py", line 1173, in mkdir
    self._accessor.mkdir(self, mode)
FileNotFoundError: [WinError 3] The system cannot find the path specified: 'F:\\ceven\\test2'
>>> os.makedirs(e)

Another question about \t:

If a directory is passed as a parameter it will not be possible to use the parameter as a raw string. os.makedirs gives the same error whether it's r'%s' or repr().

[eryksun]

FileNotFoundError: [WinError 3] The system cannot find
the path specified: 'F:\\ceven\\test2'

The Windows error code, ERROR_PATH_NOT_FOUND (3), indicates that the parent path, r"F:\ceven", does not exist. Try e.mkdir(parents=True) [1].

[1] https://docs.python.org/3/library/pathlib.html#pathlib.Path.mkdir

[eryksun]

e = Path(r'F:\ceven\test2')

Using forward slashes in the string literal is preferred, e.g. Path('F:/ceven/test2'). This avoids the problem of backslash escapes in string literals. The Path constructor parses the path and stores it internally as component parts. When the path object is needed as a string, os.fspath() returns the path using the platform's preferred path separator. A WindowsPath or PureWindowsPath uses backslash as the path separator. For example:

    >>> os.fspath(pathlib.PureWindowsPath('F:/ceven/test2'))
    'F:\\ceven\\test2'

[vincentfung]

Oh. Got it.

I thought pathlib would solve this problem completely now, without having to replace the slashes. Thank you for your patient answer.

[eryksun]

I thought pathlib would solve this problem completely now,
without having to replace the slashes.

pathlib has nothing to do with how the Python language compiles string literals. A string *literal* is Python source code that gets compiled and instantiated as a string object.

There is no technical problem with using r'F:\ceven\test2'. Using a raw string literal disables backslash escapes. But many developers find it inconvenient to have to use raw strings or to have to escape backslashes by doubling them. Plus raw string literals can't represent a path that ends with a backslash, such as C:\.

The Windows API supports forward slash as a path separator in many cases, but not always, and also not always for paths passed on the command line. So it's preferable to always normalize paths. pathlib takes care of this for you. You can initialize conveniently with forward slashes, but get a Windows path string that uses backslashes.

[vincentfung]

Thank you very much for your patient answer, I am still a developer who has just started, and it seems that I need to learn more about it.

I used repr().replace to replace with forward slashes, and also restricted paths ending in a slash to Improve reliability.

Thanks anagin. ;)