Why exception from os.path.exists()?

[Marko Rauhamaa]

"Peter J. Holzer" <hjp-python at hjp.at>:

> POSIX specifies a number of error codes which can be returned by stat():
>
> [EACCES]
>     Search permission is denied for a component of the path prefix.
> [EIO]
>     An error occurred while reading from the file system.
> [ELOOP]
>     A loop exists in symbolic links encountered during resolution of the
>     path argument.
> [ENAMETOOLONG]
>     The length of a component of a pathname is longer than {NAME_MAX}.
> [ENOENT]
>     A component of path does not name an existing file or path is an
>     empty string.
> [ENOTDIR]
>     A component of the path prefix names an existing file that is
>     neither a directory nor a symbolic link to a directory, or the path
>     argument contains at least one non- <slash> character and ends with
>     one or more trailing <slash> characters and the last pathname
>     component names an existing file that is neither a directory nor a
>     symbolic link to a directory.
> [EOVERFLOW]
>     The file size in bytes or the number of blocks allocated to the file
>     or the file serial number cannot be represented correctly in the
>     structure pointed to by buf. 
>
> [...]
>
> Note that none of these covers "file name contains an illegal character"
> for the simple reason that on POSIX systems there are no illegal
> characters.
>
> So none of these is a good choice for the errno parameter of an OSError
> to be thrown.

The natural errno value would be EINVAL, which is returned whenever a
system call is invoked with an illegal argument.


Marko