[Zope-CMF] Re: monkey patching CMFCore.utils isn't working?!?

[Florent Guillaume]

Tres Seaver wrote:
> Matt Hahnfeld wrote:
>> I am using Plone 2.1.2, w/ CMF 1.5.5.  I'm having trouble using
>> the overridden _checkPermission function in 1.5.5 to handle proxy 
>> roles on
>> a FSPythonScript.  After hacking around, I've determined the best method
>> to repair this issue is to "backport" CMF 1.6.0's function and make
>> _checkPermission call SecurityManager's _checkPermission.  I don't really
>> want to change the core libraries, so my idea was to do it as a monkey
>> patch.
>>
>> So, I added this monkey patch to one of my custom zope products:
>>
>> -----
>> from AccessControl import getSecurityManager
>>
>> def _checkPermission(permission, obj):
>>     return getSecurityManager().checkPermission(permission, obj)
>>
>> import Products.CMFCore.utils
>> Products.CMFCore.utils._checkPermission = _checkPermission
>> -----
>>
>> But every time I use _checkPermission from Products.CMFCore.utils I'm
>> still getting the old one...  Is it possible to monkey patch functions 
>> (as
>> opposed to methods)?  Any idea why this monkey patch wouldn't be working?
> 
> Other modules may have already imported it, using:
> 
>   from Products.CMFCore.utils import _checkPermission
> 
> Those modules *also* need monkey patching, because they are holding onto 
> a reference to the original object, even though you have bound a new 
> reference to that name with your monkey.

It might be possible to monkey patch only _checkPermission.func_code, 
which seems to work on simple tests, but I've never tried it in real life:

 >>> def f(a):
...     print a+1

 >>> def g(b):
...     print b+2

 >>> f(0)
1
 >>> f.func_code = g.func_code
 >>> f(0)
2

Florent

-- 
Florent Guillaume, Nuxeo (Paris, France)   Director of R&D
+33 1 40 33 71 59   http://nuxeo.com   fg at nuxeo.com