os.path.exists() returns False for certain file name

[MarkoMavrinac]

BPO	29827
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 2017-03-16.15:04:59.216>
created_at = <Date 2017-03-16.14:27:55.075>
labels = ['type-bug', 'invalid', 'OS-windows']
title = 'os.path.exists() returns False for certain file name'
updated_at = <Date 2017-03-16.15:04:59.213>
user = 'https://bugs.python.org/MarkoMavrinac'

bugs.python.org fields:

activity = <Date 2017-03-16.15:04:59.213>
actor = 'eryksun'
assignee = 'none'
closed = True
closed_date = <Date 2017-03-16.15:04:59.216>
closer = 'eryksun'
components = ['Windows']
creation = <Date 2017-03-16.14:27:55.075>
creator = 'Marko Mavrinac'
dependencies = []
files = []
hgrepos = []
issue_num = 29827
keywords = []
message_count = 3.0
messages = ['289717', '289718', '289719']
nosy_count = 6.0
nosy_names = ['paul.moore', 'tim.golden', 'zach.ware', 'eryksun', 'steve.dower', 'Marko Mavrinac']
pr_nums = []
priority = 'normal'
resolution = 'not a bug'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue29827'
versions = ['Python 2.7']

[MarkoMavrinac]

I have two files in two different folders, both on desktop.
If I try using os.path.exists() on both of them, it returns True for one file and False for the other file.
After renaming file that I got False from, I get returned True and when I rename it back, it returns False again.

File name causing the problem is "testni.wav", I assume it's anything starting with "test", but I'm sure you guys will know better. Thank you

Detailed description with screenshots can be seen here: http://stackoverflow.com/questions/42834408/os-path-exists-returning-false-for-one-and-true-for-another-file-both-files-e

[MarkoMavrinac]

I am sorry, I didn't realize \t affected how the path was recognized.

[eryksun]

In a string literal, '\t' represents a tab character (ordinal 9). Windows filenames cannot contain control characters 1, i.e. ordinals 1-31. For path literals I recommend using forward slashes and normalizing via os.path.normpath, e.g. filepath = os.path.normpath('C:/Users/mavri/Desktop/proba/testni.wav').

FYI, the way exists() is written handles any OSError as False:

    def exists(path):
        try:
            os.stat(path)
        except OSError:
            return False
        return True

In your case, stat() fails with ERROR_INVALID_NAME (123):

    >>> os.stat('\testni.wav')
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    OSError: [WinError 123] The filename, directory name, or volume label
    syntax is incorrect: '\testni.wav'