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	 be19ed77dd
			
		
	
	
		be19ed77dd
		
	
	
	
	
		
			
			There's one major and one minor category still unfixed: doctests are the major category (and I hope to be able to augment the refactoring tool to refactor bona fide doctests soon); other code generating print statements in strings is the minor category. (Oh, and I don't know if the compiler package works.)
		
			
				
	
	
		
			36 lines
		
	
	
	
		
			1.1 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			36 lines
		
	
	
	
		
			1.1 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
| """
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| There is a way to put keys of any type in a type's dictionary.
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| I think this allows various kinds of crashes, but so far I have only
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| found a convoluted attack of _PyType_Lookup(), which uses the mro of the
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| type without holding a strong reference to it.  Probably works with
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| super.__getattribute__() too, which uses the same kind of code.
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| """
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| 
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| class MyKey(object):
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|     def __hash__(self):
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|         return hash('mykey')
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| 
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|     def __cmp__(self, other):
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|         # the following line decrefs the previous X.__mro__
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|         X.__bases__ = (Base2,)
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|         # trash all tuples of length 3, to make sure that the items of
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|         # the previous X.__mro__ are really garbage
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|         z = []
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|         for i in range(1000):
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|             z.append((i, None, None))
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|         return -1
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| 
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| 
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| class Base(object):
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|     mykey = 'from Base'
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| 
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| class Base2(object):
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|     mykey = 'from Base2'
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| 
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| class X(Base):
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|     # you can't add a non-string key to X.__dict__, but it can be
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|     # there from the beginning :-)
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|     locals()[MyKey()] = 5
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| 
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| print(X.mykey)
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| # I get a segfault, or a slightly wrong assertion error in a debug build.
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