Re: [Qemu-devel] [PATCH 6/6] docker: Open dockerfiles in text mode

[Eduardo Habkost <ehabkost@redhat.com>]

On Wed, Jun 27, 2018 at 07:51:01AM -0500, Eric Blake wrote:
> On 06/26/2018 09:14 PM, Eduardo Habkost wrote:
> > Instead of treating dockerfile contents as byte sequences, always
> > open dockerfiles in text mode and treat it as text.
> > 
> > This is not strictly required to make the script compatible with
> > Python 3, but it's a simpler and safer way than opening
> > dockerfiles in binary mode and decoding the data data later.
> 
> s/data data/data/

Thanks.

> 
> > 
> > To make the code compatible with both Python 2 and 3, use
> > io.open(), which accepts a 'encoding' argument on both versions.
> 
> How does this compare to the recent change to the QAPI generators in commit
> de685ae5e?  Should we be trying to use similar mechanisms in both places?

We could do the same and use io.open(..., encoding='utf-8')
unconditionally on QAPI too, but it may be harder because of its
usage of insinstance() and the 'str' type[1] everywhere.

One solution I considered on QAPI was using
'__future__.unicode_literals' and the 'builtins.str' type from
python-future, but I don't think QAPI's specific case justify
adding a new build dependency on Python 2.7 hosts.

Adding type annotations to the QAPI code may help us sort out the
mess more easily.

[1] 'str' on Python 2.7 is more similar to the 'bytes' type on
    Python 3, but io.open(..., encoding=...) on Python 2.7
    returns 'unicode' objects (that that are more similar to the
    native 'str' type from Python 3).

-- 
Eduardo