Re: [Boost-build] explicitly-specified values of non-free feature <threading> conflict

Subject: Re: [Boost-build] explicitly-specified values of non-free feature <threading> conflict
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2018-01-17 17:46:06

AMDG

On 01/16/2018 10:01 PM, Steve Robbins via Boost-build wrote:
> 
> My tester ("Debian-Sid") stopped working December 22.  It now fails with the following 
> error.  Any idea what it means?  Or where to start looking?
> 

Okay.  I've tracked this down to the addition of
tools/check_build.

It's a result of an unfortunate combination of factors:
- Boost.Build does not allow <threading>multi in usage-requirements
- Boost.MPI tries to set <threading>multi in its usage-requirements
- Boost.Build mostly ignores the problem and it sort of works,
  except in one case: If a target has a dependency property in
  its usage-requirements.
- tools/Jamfile.v2 sets <implicit-dependency>/boost//headers (which
  is a dependency property) in its usage-requirements
- tools/check_build/test inherits this and also uses Boost.MPI,
  thus triggering the error.

Proposed solution:
- Boost.Build should ignore non-free usage requirements
  and issue a warning.

> /var/lib/jenkins/jobs/Boost-Testing-master-64/workspace/boost_bb/src/build/feature.jam:
> 779: in expand-composites from module feature
> error: explicitly-specified values of non-free feature <threading> conflict
> error: existing values: multi single

In Christ,
Steven Watanabe