empty command line arguments filtered out on windows

New submission from anton <None>:

If I run something like {{{getProcessOutput('some.exe', ('foo', '', 'bar'))}}} on windows, the empty command line argument is filtered out and the command line that is actually run is {{{'some.exe foo  bar'}}} (two spaces between foo and bar).

This can be fixed by improving the argument quoting in twisted.python.win32.cmdLineQuote:
{{{
--- twisted/python/win32.py     2009-06-10 11:01:54.753700000 +0300
+++ twisted/python/win32.py.orig        2009-06-10 11:01:22.457700000 +0300
@@ -75,7 +75,7 @@

     @return: a quoted string.
     """
-    quote = ((" " in s) or ("\t" in s) or ('"' in s) or s == '') and '"' or ''
+    quote = ((" " in s) or ("\t" in s) or ('"' in s)) and '"' or ''
     return quote + _cmdLineQuoteRe2.sub(r"\1\1", _cmdLineQuoteRe.sub(r'\1\1\\"', s)) + quote

 def quoteArguments(arguments):

}}}

The above would lead to the example command line becoming {{{'some.exe foo "" bar'}}} and {{{""}}} would be correctly unqoted as an empty argument.

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Type     : defect
Component: core
Keywords : 
Priority : normal
Nosy     : 
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http://twistedmatrix.com/trac/ticket/3876