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From: Random832 <random832@fastmail.com>
Newsgroups: comp.lang.python
Subject: Re: yield in try/finally case
Date: Thu, 03 Mar 2016 10:12:19 -0500
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On Thu, Mar 3, 2016, at 08:47, Peter Otten wrote:
> This is because the last generator uf = upperfile(...) is not garbage-
> collected and wasn't explicitly closed either.

But the program hasn't ended yet when you run your assertion.

import sys

_open = open
files = []

def myclose(self):
    print("--- closed " + self.name)
    self._close()

def open(*args, **kw):
    f = _open(*args, **kw)
    f._close = f.close
    f.close = lambda: myclose(f)
    files.append(f)
    return f

def upperfile(filename):
    with open(filename) as f:
        for line in f:
            yield line.upper()

for uf in map(upperfile, sys.argv[1:]):
    for line in uf:
        print(line, end="")
        break

print("--- end of program")

====

FOO
--- closed tmp1.txt
HAMS
--- end of program
--- closed tmp2.txt