contextlib.nested()

[brasse]

Hello!

I have been running in to some problems when using
contextlib.nested(). My problem arises when using code similar to
this:

from __future__ import with_statement

from contextlib import nested

class Foo(object):

    def __init__(self, tag, fail=False):
        print 'ctor', tag
        self.tag = tag
        if fail:
            raise Exception()

    def __enter__(self):
        print '__enter__', self.tag
        return self

    def __exit__(self, *args):
        print '__exit__', self.tag

with nested(Foo('a'), Foo('b', True)) as (a, b):
    print a.tag
    print b.tag

Here the construction of b fails which in turn means that the
contextmanager fails to be created leaving me a constructed object (a)
that needs to be deconstructed in some way. I realize that nested() is
in a tight spot here to do anything about it since it doesn't exist.
This behavior makes it hard for me to use the with statement (using
nested()) the way I want.

Has anyone else been running in to this? Any tips on how to handle
multiple resources?

Regards,
Mattias