[PATCHES] Build pytalloc for two Python versions at once, port to py3

[Andrew Bartlett]

On Mon, 2015-03-16 at 12:14 +0100, Petr Viktorin wrote:
> On 03/14/2015 10:17 AM, Andrew Bartlett wrote:
> > On Fri, 2015-03-13 at 14:00 +0100, Petr Viktorin wrote:
> [...]
> >> I believe that it's impossible to do while still keeping things clear.
> >> I did try, however, to keep the deviations from Python 3 minimal. Here
> >> they are:
> >>
> >> * PyStr (to use either PyUnicode or PyBytes depending on the version)
> >
> > Can't we code to the Python3 API, and have it map both to python2
> > strings, either as raw bytes or pushing (presumed internal mapping) UTF8
> > to UTF8?  (Yes, we really should use the unix charset, but these parts
> > of samba without unix charset == utf8 is just broken).
> 
> Unfortunately, no. A lot of the Python 3 API is also available in Python 
> 2, and using it would bring Python 3 semantics to the Python 2 version.
> 
> Specifically, to use the py3 API we'd have to use PyUnicode for all 
> human-readable strings.
> That leaves two choices for py2 behavior:
> - aliasing PyUnicode to PyString, which would not work where PyUnicode 
> is also needed in Python 2. Not to mention that alasing an existing type 
> to something else would be extremely confusing.
> - using PyUnicode everywhere, which won't work either. Even if all of 
> Samba's py2 code didn't care if it was getting str or unicode, things 
> like tp_repr (repr() implementation) fail when you return unicode in py2.

If it helps, the only place I can see PyUnicode being used is that we
accept, but do not emit, PyUnicode in the pidl DCE/RPC generated code.
I may not be grepping on the right things, but I also see no other
references to unicode, except for some .encode('utf-16-le') calls
creating password values. 

(This may help explain our ambivalence about the whole reason for
python3 in the first place)

When I get some head-space, I'm going to write about the difficulty the
Samba Team faces with this kind of project.  I spoke before about the
async ldb example, but after ntdb came up, I realise we have been here
before on other efforts.  I'm quite concerned to ensure we don't waste
your efforts, and that we are all agreed on the risks and benefits. 

Thanks,

Andrew Bartlett

-- 
Andrew Bartlett
http://samba.org/~abartlet/
Authentication Developer, Samba Team  http://samba.org
Samba Developer, Catalyst IT          http://catalyst.net.nz/services/samba