cache decorators doesn't support kwargs

[ardeois]

I'm using the decorator 'cache_region' and it's not possible to cache a function which has kwargs :

@cache_region('short_term')
def a_function(x, y=None):
  return 'whatever'

When invoking the function 'a_function', we get an exception like:

TypeError: cached() got an unexpected keyword argument 'y'

This behavior happens with any decorator for caching functions

[amol-]

The proposed patch seems to have a flaw to me. The cache key is generated from the passed **kwargs and *args, this means that for a function defined as:

def a_function(x, y=None):
    return 'whatever'

calling it as a_function(1, 2) will lead to a different cache key than a_function(x=1, y=2) this is due to the fact that joined_kwargs is constructed depending on the actually passed function arguments, so it depends on the way the arguments are passed.

You should probably pass through inspect.getcallargs before generating the cache key so that it is unrealted to the way the function is called.

[amol-]

This should now be solved by 6b89db7