Compiling with gdc vs. gdmd

[Joseph Rushton Wakeling]

On 04/04/12 14:24, Alex Rønne Petersen wrote:
> GPL extends to the build system? This is news to me... that seems a little
> overzealous... (or maybe I'm interpreting it incorrectly)
>
> But point taken. If that's how the GPL works, then that's how it is.

 From Section 1 of the GPL:

    The “Corresponding Source” for a work in object code form means all the
    source code needed to generate, install, and (for an executable work) run
    the object code and to modify the work, including scripts to control those
    activities.

To see why it matters, imagine a corporate entity releasing a large, complex 
piece of software where the code was under a free licence but the build system 
was proprietary and internal to the company.  It'd be a major block to 
practically enjoying the licence freedoms.

> I just don't think I'm seeing where the problem arises, since Waf's license is
> very permissive. But IANAL, etc. ;)

IANALE, but I think the essential point is that the GPL requires source code to 
be provided in the appropriate form for editing.  Again from Section 1:

    The “source code” for a work means the preferred form of the work for making
    modifications to it.

The fact that part of the Waf script is zipped up and therefore not immediately 
available to read might in principle be a violation here -- it's certainly a 
problem for Debian who view it as imposing an unreasonably hard burden on anyone 
wishing to tweak the build system e.g. to fix bugs.

However, what really got the Debian guys going is that what's in the zipped file 
has been processed to remove comments, whitespace etc., so it doesn't actually 
correspond to the GPL definition of the "source code".  Further, the code is a 
subset of what's provided in the Waf git repo.

It follows that there is no availability of adequate source code (in the GPL 
sense of "preferred form for making modifications") corresponding to what's in 
the Waf script.  So, there is almost certainly a GPL violation if Waf is being 
distributed as the build script for GPL (or AGPL, or LGPL) licensed software.

It's a shame, because this doesn't seem like a technically insurmountable 
problem; it's almost certainly down to lack of appreciation of these legal 
issues on the part of the Waf devs.  That's one reason why I was so concerned 
over the docs licensing -- it's such an obviously nasty thing to do where FOSS 
is concerned.

> Oh, don't worry - most discussions on the D newsgroups in general often branch
> into rather tangential discussions; people don't really mind this at all.

Thank you :-)  I'm always conscious about kicking up such discussions as a new 
and non-contributing party to a product.  Just so long as it is valuable ... :-)

> Not at all. This discussion has been enlightening to me as well.

Excellent. :-)

> All this being said, I don't know of any other good build tool for D (and GDC in
> particular) at the moment. You may have to resort to using Make and/or
> Autotools. :/

I don't mind working with the GNU Autotools at all -- I've used them for other 
projects -- but I'm concerned about the extent of their support for D.  As you 
probably know when you're setting up a configure.ac file, you usually call 
various macros checking e.g. for the presence of the language and corresponding 
compiler, and so on.  I'm not sure whether the Autotools currently have the 
macros needed to work with gdc.

I actually looked into this a few years back and exchanged a few emails with the 
autoconf/automake devs about putting those macros in place, but I quickly 
realized that the m4 scripting required was beyond me, or at least beyond the 
practical time commitment I could put in. :-(