[Scons-users] Dealing with headers appearing from Command builders

[Dirk Bächle]

Hi Matthias,

On 07.04.2015 17:07, mg at ncp-e.com wrote:
> Hello,
>
> I'm a SCons user for about three years now. First of all I wanted to
> thank the people that take care of it. It's the best build system I've
> worked with so far. It is robust, extensible and just is fun to work
> with.

thanks a lot for your positive feedback. Don't forget to tell all your friends! ;)

>
> We require a lot of third party packages for building our own
> software. To support this I've integrated a small package manager into
> SCons that is able to fetch and build the various third party packages
> and report the resulting libraries and include directories etc. back to
> SCons. I basically realized this using a Command builder that calls into
> a separate python package that provides all of this.
>
> That approach is working great so far. There is one glitch, however,
> when doing a clean build:
>
> [...]
>

To better understand the underlying problems, you could have a look at the following mail threads:

   https://pairlist4.pair.net/pipermail/scons-users/2014-December/003234.html
   https://pairlist4.pair.net/pipermail/scons-users/2014-December/003245.html
   https://pairlist4.pair.net/pipermail/scons-users/2014-December/003248.html
   https://pairlist4.pair.net/pipermail/scons-users/2014-December/003252.html

, which deal with related issues. The explanation of SCons internal processing model in

   http://pyvideo.org/video/2409/scons-software-bauen-in-python

might give you further insight too. Ditching the Command approach, and implementing customized Emitters for your package Builder(s) 
is probably the way to go. Finally, don't use SideEffect() to express dependencies...you probably want Depends(), Requires() or Clean().

Best regards,

Dirk