Re: Broken implicit DEPENDS?

[Joerg Sonnenberger <joerg%bec.de@localhost>]

On Thursday, November 16, 2023 9:20:00 PM CET Jonathan Perkin wrote:
> I have a feeling, based on the "Not yet" comments in check-shlibs, that 
> others have already been along this path, and so I wanted to get some 
> input here first before delving too far into the rabbit hole.  However, 
> it's pretty scary that we are currently shipping so many effectively 
> broken packages right now, that are only working due to the user 
> happening to have the dependencies installed via some other path.

So one of the real issues is that we have two different use cases of DEPMETHOD
in b3.mk.

Exhibit A: x11/xtrans. This is a header only package, so it marks itself as
build-only dependency. That's reasonable and shouldn't be created any
problems.

Exhibit B: audio/libmp3splt. This one is a bit cleverer than it should be, but
kind of highlights the problem seen in a couple of other places. If this
package is b3ed and the libvorbis is also desired explicitly, any using
package needs to override the value again. That is broken and requires
some fixing.  I think the correct way to address this requires a change
to the b3 logic. We should be pushing a "build-time only" marker on the
stack and handle the rest in the central logic, i.e. a package is considered
build-only if (1) DEPMETHOD is set to build or (2) all indirect includes are
with a "build-time only" marker on the stack.

Joerg