WAF 2.x upgrade for 4.9

[Andrew Bartlett]

On Fri, 2018-07-06 at 07:40 +0300, Alexander Bokovoy via samba-
technical wrote:
> On pe, 06 heinä 2018, Gary Lockyer via samba-technical wrote:
> > Can I ask why the urgency to get the WAF upgrade into 4.9.  It's going
> > to b much safer if this gets landed after the 4.9 cut-off.  My concern
> > is that changing the build system this close to a release is going to
> > cause all sorts of unnecessary pain.  Whereas if we wait until after the
> > 4.9 release we'll have 6 months to sort out any issues.
> 
> Python 2 will be dropped by Python upstream in 2020. Postponing a
> release to 2019 means we couldn't sort out distribution-wide Python 3
> migration for Samba and Samba AD targets until first half of 2019. This
> puts Fedora Project (in my case) into a dangerous state.
> 
> Waf upgrade is a first step in cleaning up Python 2 use and replacing it
> with Python 3-compatible code. Unfortunately, a reality is that it takes
> more than just porting Samba to py3 to do that. We need to make sure
> distribution as a whole deals well with that -- for example, while
> FreeIPA is using Python 3 already in Fedora 28 (current release) with
> select Samba Python modules and there we can be sure things work, the
> same couldn't be said for Samba AD path. Right now I couldn't even build
> Samba AD with Python 3 to test whether things would work at all.

I don't see how the distribution-wide stuff can come before the Python3
porting of the code is done.  Given that, why is the build-system step
urgent?  

> Note I'm talking about use outside of git master as we need to have
> supporting libraries packaged with upgraded waf. We have ~2 months until
> 4.9 release, I think it is sufficient time to sort out waf issues in
> prereleases given the analysis Andrew did to the resulting generated
> config files.

The concern is more that in the next 6 days, many developers will be
trying to land patches into master for the 4.9 freeze.  

So we don't have 2 months, we have 6 busy days.  I've seen how grumpy
folks get when their autobuilds stop working, and I wouldn't advise
being on the pointy end of that wrath. 

Given that nothing will work until 4.10 is released, and we can release
talloc, tdb, tevent, ldb at will (including after 4.9rc1), it would be
very helpful if you can justify the rush a bit more clearly.

While I'm very keen on this work in principal, I really do trust Gary's
instinct here.  

This isn't the absolute last step before a distribution package builds
and operates with python3 is it?

Thanks,

Andrew Bartlett

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