error in os.chdir

[Chris Angelico]

On Sun, Jul 1, 2018 at 12:43 PM, eryk sun <eryksun at gmail.com> wrote:
> On Sun, Jul 1, 2018 at 2:28 AM, Chris Angelico <rosuav at gmail.com> wrote:
>> On Sun, Jul 1, 2018 at 12:22 PM, eryk sun <eryksun at gmail.com> wrote:
>>>> So what if, internally, that's done by converting them to backslashes?
>>>> No Python program needs to care. In fact, there are other conversions,
>>>> too - the underlying file system is most likely using UTF-16 paths,
>>>> but your Python program needn't use UTF-16. No, it simply uses a plain
>>>> old string literal - a Unicode string. The OP need not be concerned
>>>> about any of these fiddlinesses, unless in some way they actually
>>>> affect Python.
>>>
>>> A few minor changes in in wording are both technically correct and
>>> don't make the text any more difficult to understand. You're the one
>>> blowing this up beyond proportion and making a mountain out of a small
>>> technical-correction mole hill. Please just let it pass.
>>
>> If you can show me a way in which a Python program actually needs to
>> care about any of these distinctions when dealing with files on
>> Windows, then I'll admit that the technical correction was needed. You
>> won't be shelling out to the "dir" command, for instance.
>
> Python has no built-in support for Windows file security, so a Python
> program may decided to use icacls.exe, takeown.exe, or xcopy.exe (copy
> owner/ACL). It's best in general to normalize paths when integrating
> an external program -- unless you've already checked that the
> program(s) you're running support forward slash without a problem.
> Checking this in each case isn't worth the trouble when it's so simple
> to call normpath(). Doing a quick test isn't sufficient. Programs that
> fail in this case do so in different ways and not always consistently.
> Using forward slash may work in some cases (e.g. passing a explicit
> file vs passing a wildcard pattern), which may give someone a false
> perception that the program intentionally supports forward slash as a
> path separator, when it's only working by accident of implementation.

Cool. Okay, so for people who don't know about pywin32, it's important
to properly wrap up arguments to some of the external programs you
might need. I'll grant you that. Internally, use forward slashes; then
when you need to shell out to something, you process the arguments
into something that will be accepted.

ChrisA