I just did something that depending on your viewpoint on coding, is either an insult to God and humanity, or absolutely brilliant.

hack.py

   #
   # I inherited a large code base, where hundreds of code paths end up
   # calling "common_function_called_in_gazillion_places". 
   #
   # And the need arose for this function to access the HTTP request's
   # headers... 
   #
   # What to do? Refactor all the places leading up to here? In a dynamically
   # typed language, with no compiler to tell us the places to refactor?
   #
   # NO - let's hack the universe instead.
   
   def get_the_request():
      """
      Look up the call stack to see if one of our callers has "self.request"
      (i.e. the Pyramid request) and if so, return it
      """
       for f in inspect.stack():
           if 'self' in f[0].f_locals:
               self = f[0].f_locals['self']
               if hasattr(self, 'request'):
                   return self.request
       else:
           return None

   def common_function_called_in_gazillion_places( variables, action ):
       ...      
       # Get the request from our callers, and extract the IP from it
       request = get_the_request()
       if request is not None:
           ip_addr = request.remote_addr
           if 'X-Forwarded-For' in request.headers:
               ip_addr = request.headers['X-Forwarded-For']
           if ip_addr not in ['127.0.0.1', 'localhost'] and \
                   isinstance(ip_addr, (str,unicode)):
               event_data['context'] = {'ip': ip_addr}
            ....
   # TADA!!!
   #
   # OK, now I can burn in programmer Hell - for all eternity.

@ttsiodras you could probably implement this method as the author has, but add some logging to it, then attempt a find/replace, then periodically check your logs. You should be able to find any calls you missed and replace them over time while retaining some form of backwards compatibility.

@ttsiodras I had to do something similar in 2009 for a trac extension, for the same exact reason, so definitely absolutely brilliant, ;) . https://gist.github.com/seanjensengrey/84beab9d6f907c0dc433

Frame hacks are what make Python, Python. See http://farmdev.com/src/secrets/framehack/

Another option would be to put in a fixme into function_called_everywhere that logs all the invocation points.

def fixme(msg):
        print >>sys.stderr,"fixme:" + sys._getframe().f_code.co_filename + ":" + \
                sys._getframe().f_back.f_code.co_name + ":" + \
                str(sys._getframe().f_back.f_lineno) + ":" + msg

Effectively what you have done is enable dynamic scope for a lexically scoped language. One could also think of dynamic scope as a form of execution context or lightweight dependency injection.

@bertjwregeer Thanks - good to know!