[Twisted-Python] Wrapping functions that return deferreds

[Ross Burton]

Hi,

I have a library that has a call() method, which returns a Deferred.  My
application used to just use .addCallback() but obviously that doesn't
have any error handling.  I then switched to .addCallbacks() so that I
could call a common error handler (to pop up a dialog) but that got
tedious to add to every invocation so I thought I'd be cunning and wrap
the call() method.

def wrap_deferred (func):
    def wrapped(*args, **kwargs):
        d = func (*args, **kwargs)
        d.addErrback (handle_twisted_error)
        return d
    return wrapped

# flickr is the object, call is the method I'm overriding
flickr.call = wrap_deferred (flickr.call)

# Then later in my app
flickr.call(foo).addCallback(handleFoo)

However, this doesn't work: I get the standard unhandled error in
deferred handling.  Can anyone spot the mistake I'm making?

Thanks,
Ross
-- 
Ross Burton                                 mail: ross at burtonini.com
                                          jabber: ross at burtonini.com
                                     www: http://www.burtonini.com./
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