Damn, detaching the intermediate buffered stream is a bit more awkward. The difference between the “io” and “_pyio” implementations boils down to:

* io.BufferedReader/Writer/RWPair.name properties raise a ValueError if the stream is detached
* _pyio._BufferedIOMixin.name property returns “self.raw.name”. When detached, “self.raw” is None, so this causes an AttributeError.

This is significant because io.TextIOWrapper.__repr__() only handles AttributeError when accessing “self.buffer.name”. The best option that I can think of to fix this is to make all the repr() implementations handle this ValueError exception.