[Python-Dev] self._backupfilename in fileinput

[Guido van Rossum]

> Working my way through the unqualified except: clauses, I found one in
> fileinput.py that looks very straightforward:
> 
>     try: os.unlink(backupfilename)
>     except: pass
> 
> To make sure that OSError was all that could be raised I started looking at
> what values backupfilename could assume.  Then I started looking at
> self._backupfilename.  This weird beast takes on values of three distinct
> types: None, 0, and various strings.  

If you read the context of the try/except clause, it's clear that it
can't be None or 0 at that point.

> While it's not technically broken, is this something worth fixing?  My
> inclination is to just add OSError to the except clause and let someone else
> worry about fixing something that's ugly but not really broken.

Note that None and 0 are used for the same purpose.  I think 0 is used
to avoid referencing any globals in code called from the __del__
method.  You might change the code to use "" instead of None or 0, but
I wouldn't bother.

--Guido van Rossum (home page: http://www.python.org/~guido/)