Re: [Qemu-devel] [PATCH] scripts: Support building with Python 3

[Markus Armbruster <armbru@redhat.com>]

Stefan Hajnoczi <stefanha@gmail.com> writes:

> On Sat, Aug 19, 2017 at 10:58:44PM -0700, David Michael wrote:
>> This allows building with "./configure --python=python3", where
>> the python3 program is at least version 3.6.  It preserves
>> compatibility with Python 2.  The changes include:
>> 
>>   - Avoiding "print" usage
>>   - Using bytes with files opened in binary mode
>>   - Switching .iteritems() to .items()
>>   - Adding fallback imports for functions moved to other modules
>> 
>> Signed-off-by: David Michael <fedora.dm0@gmail.com>
>> ---
>> 
>> Hi,
>> 
>> I've been applying these changes when building on Fedora 26, which does
>> not include any Python 2 packages by default.  It was tested with Python
>> 2.7 and 3.6.
>> 
>> I just saw the list of scripts that need updating on the mailing list,
>> and this doesn't cover all of them, but it is enough to build a binary
>> for running virtual machines with KVM.  Maybe it is still useful as a
>> starting point.
>> 
>> Thanks.
>
>
> Markus,
> You wanted to discuss the general direction of Python version support
> before applying this.

Dan has since posted competing patches.

> Has consensus been reached?

I need to decide how much I hate supporting both Python 2 and Python 3,
and that involves looking at both patch sets in more detail.

QAPI is a rather busy subsystem, and right now my review queue is in a
state where I have to decide whom to annoy and disappoint with overly
long delays.

Given the choice between addressing a problem that doesn't really exist,
yet (Python 2 going away) and addressing problems that are hurting us
*now* (such as QAPI's inability to express compile-time conditionals), I
have to prioritize the latter.  I wish I wouldn't have to make such
choices, and I apologize for the inconvenience.