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

[Markus Armbruster <armbru@redhat.com>]

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.

https://pythonclock.org/