[New-bugs-announce] [issue12020] Attribute error with flush on stdout, stderr

[James Hutchison]

New submission from James Hutchison <jamesghutchison at gmail.com>:

When upgrading from Python 3.1 to Python 3.2 I noticed that when my program closed it printed out a non-consequential AttributeError Exception. My program had a custom class that replaced stdout and stderr for use in a piped program (it flushed the buffer after every print statement)

I was able to reduce my code down to this simple test case that will reproduce the issue. Note that this doesn't show up in idle.

code:
import sys
from time import sleep
import subprocess

python31loc = r"C:\python31\python.exe";
python32loc = r"C:\python32\python.exe";
myname = "attributeError.py";

class FlushFile(object):
    #"""Write-only flushing wrapper for file-type objects."""
    def __init__(self, f):
        self.f = f
        try:
            self.encoding = f.encoding;
        except:
            pass;
    def write(self, x):
        self.f.write(x)
        self.f.flush()

# sets stdout and stderr to autoflush
def setAutoFlush():
    if sys.__stdout__ != None: # will be None in IDLE
        sys.stdout = FlushFile(sys.__stdout__);
        sys.stderr = FlushFile(sys.__stderr__);

if __name__ == "__main__":
    setAutoFlush();
    if(len(sys.argv) == 1):
        print("Testing python 3.1");
        output = subprocess.check_output("%s %s -output" % (python31loc, myname));
        print("Should see no error");
        print("Testing python 3.2");
        output = subprocess.check_output("%s %s -output" % (python32loc, myname));
        print("Should see no error");
        sleep(16);


Output:
Testing python 3.1
Should see no error
Testing python 3.2
Exception AttributeError: 'flush' in <__main__.FlushFile object at 0x00C347F0> i
gnored
Should see no error

----------
components: IO, Windows
messages: 135347
nosy: Jimbofbx
priority: normal
severity: normal
status: open
title: Attribute error with flush on stdout,stderr
type: behavior
versions: Python 3.2

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue12020>
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