Re: [Qemu-devel] [Qemu-block] [PATCH v3] python: Use io.StringIO

[Kevin Wolf <kwolf@redhat.com>]

Am 11.10.2018 um 16:01 hat Markus Armbruster geschrieben:
> Paolo Bonzini <pbonzini@redhat.com> writes:
> 
> > On 11/10/2018 13:33, Kevin Wolf wrote:
> >> 045 1s ...        [13:31:47] [13:31:47] [failed, exit status 1] - output mismatch (see 045.out.bad)
> >> --- /home/kwolf/source/qemu/tests/qemu-iotests/045.out  2017-01-24 14:49:48.000000000 +0100
> >> +++ /home/kwolf/source/qemu/tests/qemu-iotests/045.out.bad      2018-10-11 13:31:47.266876850 +0200
> >> @@ -1,5 +1,26 @@
> >> -...........
> >> -----------------------------------------------------------------------
> >> -Ran 11 tests
> >> -
> >> -OK
> >> +Traceback (most recent call last):
> >> +  File "045", line 178, in <module>
> >> +    iotests.main(supported_fmts=['raw'])
> >> +  File "/home/kwolf/source/qemu/tests/qemu-iotests/iotests.py", line 698, in main
> >> +    unittest.main(testRunner=MyTestRunner)
> >> +  File "/usr/lib64/python2.7/unittest/main.py", line 95, in __init__
> >> +    self.runTests()
> >> +  File "/usr/lib64/python2.7/unittest/main.py", line 232, in runTests
> >> +    self.result = testRunner.run(self.test)
> >> +  File "/usr/lib64/python2.7/unittest/runner.py", line 151, in run
> >> +    test(result)
> >> +  File "/usr/lib64/python2.7/unittest/suite.py", line 70, in __call__
> >> +    return self.run(*args, **kwds)
> >> +  File "/usr/lib64/python2.7/unittest/suite.py", line 108, in run
> >> +    test(result)
> >> +  File "/usr/lib64/python2.7/unittest/suite.py", line 70, in __call__
> >> +    return self.run(*args, **kwds)
> >> +  File "/usr/lib64/python2.7/unittest/suite.py", line 108, in run
> >> +    test(result)
> >> +  File "/usr/lib64/python2.7/unittest/case.py", line 431, in __call__
> >> +    return self.run(*args, **kwds)
> >> +  File "/usr/lib64/python2.7/unittest/case.py", line 406, in run
> >> +    result.addSuccess(self)
> >> +  File "/usr/lib64/python2.7/unittest/runner.py", line 62, in addSuccess
> >> +    self.stream.write('.')
> >> +TypeError: unicode argument expected, got 'str'
> >> Failures: 045
> >> Failed 1 of 1 tests
> >> 
> >> $ /usr/bin/env python --version
> >> Python 2.7.15
> >
> > Indeed, io.StringIO exists in Python 2.7 but it's different!  If Python
> > 2 code is not unicode-friendly (it almost never is) it should use
> > StringIO.StringIO, for example 'six' defines
> >
> >   six.StringIO:
> >     This is an fake file object for textual data. It’s an alias for
> >     StringIO.StringIO in Python 2 and io.StringIO in Python 3.
> >
> >   six.BytesIO:
> >     This is a fake file object for binary data. In Python 2, it’s an
> >     alias for StringIO.StringIO, but in Python 3, it’s an alias for
> >     io.BytesIO.
> >
> > So the solution seems to be a try/except (and then, better move the
> > "from X import StringIO" to the top of the file then, rather than
> > keeping it in def main).
> >
> > Paolo
> 
> I think we need to invest more resources in Python 2/3 compatiblity, or
> else we'll miss our hard deadline of January 1, 2020.

Did we decide until when we want to support Python-2-only hosts in QEMU?

I think I would be okay with just getting rid of Python 2 support and
always using Python 3 instead of trying to write code that works with
both. Python 3 was installed for me, but the scripts didn't use it.

Kevin