[Python-Dev] Possible py3k io wierdness (original) (raw)

brian at sweetapp.com brian at sweetapp.com
Sun Apr 5 00:35:32 CEST 2009

Hey,

I noticed that the call pattern of the C-implemented io libraries is as follows (translating from C to Python):

class _FileIO(object): def flush(self): if self.__IOBase_closed: raise ...

def close(self): self.flush() self.__IOBase_closed = True

class _RawIOBase(_FileIO): def close(self): # do close _FileIO.close(self)

This means that, if a subclass overrides flush(), it will be called after the file has been closed e.g.

import io class MyIO(io.FileIO): ... def flush(self): ... print('closed:', self.closed) ... f = MyIO('test.out', 'wb') f.close() closed: True

It seems to me that, during close, calls should only propagate up the class hierarchy i.e.

class _FileIO(object): def flush(self): if self.__IOBase_closed: raise ...

def close(self): _FileIO.flush(self) self.__IOBase_closed = True

I volunteer to change this if there is agreement that this is the way to go.

Cheers, Brian