[PATCH 29] Re: Disabling Python Modules

[Andrew Bartlett]

On Wed, 2017-01-25 at 23:56 -0500, Ian Stakenvicius wrote:
> On 25/01/17 03:29 AM, Stefan Metzmacher wrote:
> > Hi Ian,
> > 
> > > I can't be certain, but I think that may indeed be the last of
> > > them.
> > > All wscript_build files that contain modules with deps= including
> > > py*util, and LIBPYTHON, are now all covered.
> > 
> > I know I'm late in the discussion, but is there a chance
> > that we could avoid all changes like this:
> > 
> > -bld.SAMBA3_PYTHON('pys3param',
> > +if not bld.env.disable_python:
> > +    bld.SAMBA3_PYTHON('pys3param',
> > 
> > And just to that globally within SAMBA_PYTHON()
> > instead of changing each caller?
> 
> 
> I considered doing that, but decided against it due to the fact that
> this hides too much from the wscript_build of each module.  When a
> bld.env.disable_python conditional exists it makes it clear that all
> components the conditional applies to (whether SAMBA_PYTHON() or not,
> and there's more than a few that aren't SAMBA_PYTHON()).
> 
> 
> 
> > [...]
> > 
> > For all others we should use something like
> > enabled=bld.PYTHON_BUILD_IS_ENABLED(),
> > see git grep 'enabled=' for examples.
> 
> 
> Is this just for style? or..

No, it is more than style.  It allows the build system to know that the
 name of the target subsystem exists, but it not in use.  This allows
dependencies to be resolved as nothing, rather than having 'if python'
in dep strings.  While this may just move the dep problem to the C
layer, it allow an #ifdef at that layer.  

It is also cleaner, in general, and while not totally consistent, it is
how we have tried to handle other features.  

> > I think we should also have the --disable-python option
> > near to the --extra-python option within
> > buildtools/wafsamba/wscript, so that it is also available
> > for the standalone builds of talloc, tevent, tdb and ldb.
> 
> 
> --disable-python is already in the standalone builds, I don't recall
> patching that in except maybe for one of those; most if not all of
> the
> changes to those modules was to allow the pre-existing
> --disable-python functionality to apply when it's _not_ being built
> standalone.

I think having this all in one place is still a good idea however.

> > 
> > For the samba build I think --disable-python give an error
> > unless --without-ad-dc is also given as an ad-dc really requires
> > python bindings.
> 
> 
> I believe I tested this one and it works out fine

I'm sorry, the Samba AD DC strictly requires python.  I don't know what
you tested (presumably just that the binaries built), but building with
the AD DC enabled needs to fail totally and early, to save everybody
time and hair.

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