When a socket is transformed into a file object using
the makefile() method, the resulting object read()
behaviour requires that read(N)
returns N characters or that the end of stream be reached.

This causes problems with XML parsers which call
read(BufferSize) to
get "something", not necessarily a full buffer.

The following patch adds a "lazy" attribute to each
socket._fileobject
instance, the default being set to False in order to be
backward
compatible. If this attribute is set to True, read(N)
will return at least
one character unless the end of stream is reached, and
no more than
N characters.

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Note: the original problem description came by Pierre
Palatin <pierre.palatin@enst.fr>.

It seems there is very little interest in this patch; it also has a few problems:

- it does not include changes to the documentation and the test suite
- the feature can be implemented in a fairly easy way by inheriting from _fileobject;
   you just have to delegate read() nearly directly to recv.
- [IMO] "lazy" is a bad name for this feature; it has more to do with whether 
   it is blocking or not.
- I don't believe the patch can solve the original problem in all cases: it very much depends on how often the XML parser invokes .read()

For these reasons, I'm rejecting the patch.