Please file a bug. On May 6, 2011 5:17 PM, "Daniel Holth" wrote:

I just learned about Python internals from The ZODB transaction module. In

Python < 2.7, the module works as a transaction manager. More or less:

manager = Foo() __exit__ = manager.__exit__ __enter__ = manager.__enter__

After Python 2.7, it doesn't work.

import transaction with transaction: pass

...

...

...

AttributeError: __exit__

It should be obvious to even the most casual observer that the exception

is because, after Python 2.7, the with: statement has its own opcode that bypasses transaction.__getattribute__('__exit__') -> transaction.__dict__['__exit__']. Instead, CPython calls special_lookup(), looks for __exit__ on the module type, not the instance, doesn't find it, and raises the AttributeError.

Instead,

import sys sys.__exit__

...

...

...

AttributeError: 'module' object has no attribute '__exit__'

The interpreter should at least explain the AttributeError in the same way

as it does when the user triggers it directly.

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