__getattr__ possible loop

[Gabriel Genellina]

At Thursday 28/12/2006 14:01, Maksim Kasimov wrote:

> > Nothing so clever. dir() eats and ignores all exceptions, so when you
> > hit the recursion limit it eats the RecursionLimitExceeded exception
> > and continues merrily along the way. This is probably not good
> > behavior...
> >
> > class Foo:
> >    def __getattr__(self, attr):
> >        raise SystemExit, "Don't call me, again, ever"
> >
> > f = Foo()
> > f.method() #dies correctly
> > dir(f) #continues happily
>
>can't understand - what kind of problem you tried to fix in that way?
>if __getattr__ just raise some exception, it needless to define it at all.

The problem is, dir() blindly eats *all* exceptions, including the 
RecursionLimitExceeded on the original post, this SystemExit, 
KeyboardInterrupt, etc. It shouldn't.
Perhaps this example (esencially the same thing) is a bit more clear:

import sys
class Foo:
     def __getattr__(self, attr):
         print "About to exit program"
         sys.exit(1)

f = Foo()
dir(f)
print "You should not see this line"


-- 
Gabriel Genellina
Softlab SRL 


	

	
		
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