Because that's how I caused the exception in
Ubuntu--shutil.launch('file_that_doesnt_exist'). That's why I changed the
message to "file may not exist" for both 2 and 4, but should probably prove
that 2 sometimes happens when the file does exist (like with permission or
visiblity/hidden errors in some OSes).

Interestingly I got it to quietly, insidiously fail on Ubuntu by passing it
a path to an empty file named empty.exe with the executeable bit set (but
permissions and executable bit didn't seem to make a difference). No app
was launched (or too quickly disappeared for me to see) and shutil.launch()
did not complain.

On Tue, Apr 24, 2012 at 1:58 AM, Chris Rebert <report@bugs.python.org>wrote:

>
> Chris Rebert <pybugs@rebertia.com> added the comment:
>
> Hobs, why is exit code 4 of xdg-open (which the manpage describes as the
> extremely generic "The action failed.") interpreted as FileNotFoundError in
> your new version?
>
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> <http://bugs.python.org/issue3177>
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