don't double-decorate in `flag_calls`

IPython/utils/decorators.py

@@ -1,54 +1,58 b''
 # encoding: utf-8
 """Decorators that don't go anywhere else.
 
 This module contains misc. decorators that don't really go with another module
 in :mod:`IPython.utils`. Beore putting something here please see if it should
 go into another topical module in :mod:`IPython.utils`.
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Code
 #-----------------------------------------------------------------------------
 
 def flag_calls(func):
     """Wrap a function to detect and flag when it gets called.
 
     This is a decorator which takes a function and wraps it in a function with
     a 'called' attribute. wrapper.called is initialized to False.
 
     The wrapper.called attribute is set to False right before each call to the
     wrapped function, so if the call fails it remains False.  After the call
     completes, wrapper.called is set to True and the output is returned.
 
     Testing for truth in wrapper.called allows you to determine if a call to
     func() was attempted and succeeded."""
+    
+    # don't wrap twice
+    if hasattr(func, 'called'):
+        return func
 
     def wrapper(*args,**kw):
         wrapper.called = False
         out = func(*args,**kw)
         wrapper.called = True
         return out
 
     wrapper.called = False
     wrapper.__doc__ = func.__doc__
     return wrapper
 
 def undoc(func):
     """Mark a function or class as undocumented.
     
     This is found by inspecting the AST, so for now it must be used directly
     as @undoc, not as e.g. @decorators.undoc
     """
     return func