Does This Scare You?

[eryk sun]

On Mon, Aug 22, 2016 at 12:39 PM, Chris Angelico <rosuav at gmail.com> wrote:
>
> Nope. On Windows, you would try/except it. There are myriad other ways

No, I would not rely on exceptions in this case. Both \\.\CON and
\\.\NUL can be opened for both reading and writing, so you may not
detect the problem.

I think it's best to check for this via os.path.abspath, which calls
GetFullPathName, which is implemented by RtlGetFullPathName_Ustr,
which is exactly what RtlDosPathNameToNtPathName_U uses to normalize a
path before it converts it to the NT namespace.

> or just slap some extra text onto the beginning or end of the file name
> (beginning meaning "after the last slash", not the beginning of the file
> *path*) and you're safe.

Adding to the beginning is the safe bet without having to worry about
the rules for trailing spaces, dots, and colons at the end of the
name. Adding a single underscore prefix will suffice (or however many
to make a unique name) if for some reason you can't ask the user for a
new name.