pythonw in py3k sets std{in,out,err} to None

The print statement works without error, even though the stdio file objects are instances
of None. Since they are instances of None, however, the encoding attribute will not
exist, so protect blind attribute access of std{in,out,err} by using a new function, get_stream_enc.

IPython/core/splitinput.py

@@ -53,7 +53,8 b' def split_user_input(line, pattern=None):'
     and the rest.
     """
     # We need to ensure that the rest of this routine deals only with unicode
-    line = py3compat.cast_unicode(line, sys.stdin.encoding or 'utf-8')
+    encoding = py3compat.get_stream_enc(sys.stdin, 'utf-8')
+    line = py3compat.cast_unicode(line, encoding)
 
     if pattern is None:
         pattern = line_split

IPython/frontend/terminal/interactiveshell.py

@@ -319,7 +319,7 b' class TerminalInteractiveShell(InteractiveShell):'
 
         for i in range(hlen - hlen_before_cell):
             self.readline.remove_history_item(hlen - i - 1)
-        stdin_encoding = sys.stdin.encoding or "utf-8"
+        stdin_encoding = py3compat.get_stream_enc(sys.stdin, 'utf-8')
         self.readline.add_history(py3compat.unicode_to_str(source_raw.rstrip(),
                                     stdin_encoding))
         return self.readline.get_current_history_length()

IPython/utils/io.py

@@ -87,9 +87,9 b' class IOTerm:'
         self.stderr = IOStream(stderr, sys.stderr)
 
 # setup stdin/stdout/stderr to sys.stdin/sys.stdout/sys.stderr
-stdin = IOStream(sys.stdin)
-stdout = IOStream(sys.stdout)
-stderr = IOStream(sys.stderr)
+stdin = sys.stdin if not sys.stdin else IOStream(sys.stdin)
+stdout = sys.stdout if not sys.stdout else IOStream(sys.stdout)
+stderr = sys.stderr if not sys.stderr else IOStream(sys.stderr)
 
 
 class Tee(object):

IPython/utils/py3compat.py

@@ -11,14 +11,22 b' orig_open = open'
 def no_code(x, encoding=None):
     return x
 
+# to deal with the possibility of sys.std* not being a stream at all
+def get_stream_enc(stream, default=None):
+    if not hasattr(stream, 'encoding') or not stream.encoding:
+        return default
+    else:
+        return stream.encoding
+
 def decode(s, encoding=None):
-    encoding = encoding or sys.stdin.encoding or sys.getdefaultencoding()
+    encoding = get_stream_enc(sys.stdin, encoding) or sys.getdefaultencoding()
     return s.decode(encoding, "replace")
 
 def encode(u, encoding=None):
-    encoding = encoding or sys.stdin.encoding or sys.getdefaultencoding()
+    encoding = get_stream_enc(sys.stdin, encoding) or sys.getdefaultencoding()
     return u.encode(encoding, "replace")
-    
+
+
 def cast_unicode(s, encoding=None):
     if isinstance(s, bytes):
         return decode(s, encoding)

IPython/utils/text.py

@@ -47,7 +47,7 b' def getdefaultencoding():'
     and finally to sys.getdefaultencoding() which is the most conservative option,
     and usually ASCII.
     """
-    enc = sys.stdin.encoding
+    enc = py3compat.get_stream_enc(sys.stdin)
     if not enc or enc=='ascii':
         try:
             # There are reports of getpreferredencoding raising errors