[maemo-developers] Optional build dependencies (e.g. for fremantle)

[From: Guillem Jover]

On Wed, 2009-03-18 at 13:50:00 +0100, ext Till Harbaum / Lists wrote:
> Am Dienstag 17 März 2009 schrieb Till Harbaum / Lists:
> > > Build-Depends: would-like-to-have-pkg1|harmless-pkg2,
> > >     would-like-to-have-pkg2|harmless-pkg2, ...
> > I'll give it a try.

> Ok, first try yesterday was
> Build-Depends: maemo-version-dev, tablet-browser-interface-dev|maemo-version-dev, ...
> 
> This did not install tablet-browser-interface-dev. There seems to be
> some optimization somewhere that makes such a shortcut impossible.

There's no optization of any kind going on here. You request a
dependency to be fullfilled and maemo-version-dev does that, so
there's no point in also installing tablet-browser-interface-dev.

> So i just tried:
> Build-Depends: maemo-version-dev, tablet-browser-interface-dev|devscripts, ...
> 
> Which works fine and pulls tablet-browser-interface-dev in. What about the package
> to use for this? Such a packet has some limitations:
> 
> - It must not be a dependency of anything else the build depends upon. E.g. things
>   like libpng-dev will likely always be loaded due to dependencies from the gui
>   libs.
> - It must always be present
> - It must be something an application will normally never need to build successfully 
>   (it should never become a real dependency)
> 
> This seems to be true for devscripts. Any other suggestion?

Yes, do *not* do that, it's a major hack, and it might stop working at
any time, you cannot control if some of the other Build-Depends will at
any point start pulling devscripts (or any phony package you want to
add there).

The clean and proper way to do this is to branch the packaging, in
Debian, packages always target the latest (sid), and often people do
backports for old releases (oldstable, stable, etc).

regards,
guillem