rb-site fails to detect memcache when installed from an egg

 






 

 


  Review Request #843
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  Created April 28, 2009 and submitted

 


















 

  

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  ehuss
 









 
 

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rb-site fails to detect the "memcache" module when memcache is installed as an egg.  Something about imp.find_module does not honor sys.path_hooks and doesn't use the zipimporter.  This appears to be true in 2.4, 2.5, and 2.6.

 








  


 
 

  
Ran "rb-site install", now properly detects memcache installation.

 







 









 





  








 









 






  

 








 














 





 

  

   





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ehuss


    
   


  

  

  



    




  1. 
 
    
  
    
   
    BTW, pkgutil.find_loader() seems to do the right thing in terms of examining sys.path_hooks, but it's not documented in the official Python docs, so I don't know if you'd rather use that (I'm not sure if the original intent was to avoid __import__ to avoid any side effects of actually importing the module).
    
  
    
 
    

 
    
  


    
 
    
 
      

  


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      Python 2.4 doesn't seem to have pkgutil.find_loader. The import should be fine for our needs here.
      
 
      

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    That's good to know, and really annoying. We do a bunch of these checks in reviewboard/admin/checks.py, too, and I haven't seen anyone hit these issues... Hmm...


I think doing an import is fine. I was just going to avoid actually importing, but if we need to, that's fine.
    
  
    
 
    

 
    
  


    
 
    
 
      

  

 
    


    

 
    

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       /trunk/reviewboard/contrib/tools/rb-site
       


        (Diff revision 1)


       
      
     
    
        
    
     
     
    

     
     
    

        
   
    
  
    
 
    

   
    
    
    





    
    Python 2.4, I believe, will grumble loudly about this, because it doesn't provide default arguments. This should be more like:

   __import__(name, {}, {}, [])
    
  
    
 
    

 
    
  


    
 
    
 
      

  


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      2.4 seems to be optional, too.  From the source: PyArg_ParseTuple(args, "s|OOO:__import__",

As for not running into the problem very often, it is somewhat rare to have a Zipped egg (this is only a problem for zipped ones -- unzipped eggs work okay because find_module honors .pth files).  For one reason or another, eggs tend not to be zip-safe (with extension Modules, for example), so that's why it probably hasn't shown up much.  I see in checks.py that you ran into a problem with importing DNS, for example, but Pygments works because it installs in unzipped format.
      
 
      

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      You're right. I was thinking back to a problem I hit before, and it wasn't default arguments, it was using keyword arguments. I wanted to specify the last argument as a keyword argument instead of providing the other defaults, and couldn't in 2.4. Defaults work fine.
      
 
      

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    Committed as r1944.
    
  
    
 
    

 
    
  


    
 
    
 
      

  

 
    


    

 
    

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