Attempting to use os.path.exists on a Windows drive that is a mobile device mount point with nothing mounted pops up a dialog asking to insert a device. This makes it impossible to search a set of drives for a specific file without the possibility of unnecessary user interaction -- for example looking for the drive that has a specific flash drive inserted.

This behavior is likely related to bug 9035 regarding "os.path.ismount" behavior on Windows.

The more correct behavior (IMO) would be to quietly return exists=False for drives with nothing mounted. In fact, I tried the same operation with Java and Ruby programs, and both simply return false with no popup.

Does it change something if you insert in your script (in 3.3):
    import msvcrt
    msvcrt.SetErrorMode(msvcrt.SEM_FAILCRITICALERRORS)

Thanks for the prompt reply!

Your suggested change does change the behavior to exactly the way I think
it should work by default. Tried it on both Windows 7 and Vista; no popups
when accessing a "mobile mount" drive with nothing in it, just quietly
reports False.

I vote for making this the normal behavior of these "file exists" sort of
operations.

Hmm, I notice that msvcrt.SetErrorMode is not discussed in the current
Python 3 Standard Library docs...  :-)

Bob

On Wed, Mar 27, 2013 at 6:40 AM, Amaury Forgeot d'Arc <
report@bugs.python.org> wrote:

>
> Amaury Forgeot d'Arc added the comment:
>
> Does it change something if you insert in your script (in 3.3):
>     import msvcrt
>     msvcrt.SetErrorMode(msvcrt.SEM_FAILCRITICALERRORS)
>
> ----------
> nosy: +amaury.forgeotdarc
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <http://bugs.python.org/issue17551>
> _______________________________________
>

Bob, when replying by email, please snip everything except your reply, and perhaps a specific small quote.

Since the doc says exists returns True or False, raising a popup seems like a bug to be fixed.

Thanks Terry. I agree that it's a bug.

And, in the future I'll be more careful about trimming the "history" from
my messages  :-)

Bob