Re: [Boost-build] [boost] [release] Boost 1.67.0 Beta 1 Release Candidate 1

Subject: Re: [Boost-build] [boost] [release] Boost 1.67.0 Beta 1 Release Candidate 1
From: Daniel James (dnljms_at_[hidden])
Date: 2018-03-11 13:59:53

On 11 March 2018 at 13:27, Stefan Seefeld via Boost
<boost_at_[hidden]> wrote:
>
> I wonder whether anyone from the Boost.Build project would be able to
> comment, and can explain the error message.
> It's true I relatively recently added
> https://github.com/boostorg/python/commit/d4d41d94aecc9f8098aabd3587fcb95458451f71,
> but I don't see how this could cause the observed error (which doesn't
> seem to be about a failed Python detection, but about an internal
> Boost.Build error (to detect the `python.python_for_extensions` rule).
>
> I can't reproduce the problem myself. From the generated output it seems
> as if passing `--without-python` would suppress the failure, but that
> hadn't been necessary before, or has it ?

If it wasn't clear, I found that commit by moving python to a
different directory so that boost build wouldn't find it, then running
the build with different versions of the boost python module. Before
the commit there would be a warning about python, but no error. After
that commit the build would fail with an error.

My guess is that 'python_for_extensions' is only defined when python
is installed, and the old 'rule lib_boost_python ( version )' would
only process its requirements as needed, if python wasn't installed,
the build would be cancelled and it wouldn't be run. But perhaps the
requirements for 'lib boost_python' are always processed, whether or
not python is installed.