Turning a signature-changing decorator into a signature-preserving one

[Gustavo Narea]

On Feb 16, 4:59 pm, Gustavo Narea <m... at gustavonarea.net> wrote:
> On Feb 16, 4:40 pm, Michele Simionato <michele.simion... at gmail.com>
> wrote:
>
>
>
> > > It was broken from the beginning on Pylons.
>
> > > I'm a TurboGears 2 core developer, and TurboGears is powered by Pylons
> > > as of version 2. The decorator has always worked in TurboGears because
> > > of the way TG finds the action arguments, but now I'm working to make
> > > it work in Pylons too, but this is the only problem that has stopped
> > > me from making it work under Pylons.
>
> > > Thanks.
>
> > I see. I would ask on the Pylons list. I suspect a bound method is
> > passed and that you will
> > need to extract the corresponding function with .im_func, then making
> > sure that you pass
> > the self argument correctly. But this is wild guess since I have no
> > idea of how Pylons decorators
> > work internally as compared to TurboGears decorators.
>
> I've not seen anything special in Pylons or TurboGears 2 decorators,
> except that they are all functions that use the decorator package --
> while my decorator is a class that doesn't use the decorator package
> yet.
>
> My attempt to turn that decorator into a signature preserving one
> using the decorator packages fails even on TurboGears 2. As of
> decorator 3.0.1, I get this error:
>     TypeError: You are decorating a non function: <unbound method
> SecurePanel.__before__>
>
> Isn't this caused by the fact that my decorator is a class, or the way
> such a class is defined (whose code is in the first post of the
> thread)? I can turn it into a function because I'm sure I'll work --
> although I wanted a class to make it easier to customize.
>
> Thanks.


This is another attempt, where the decorator is a still a class but
uses an auxiliary function:
http://paste.chrisarndt.de/paste/38bf8a8443614464968d424e1f2d4182

However, that raises this exception:
http://paste.chrisarndt.de/paste/f90bc9a058254e2ca5660882011752a7?wrap=no