Re: [BuildStream] bst show all and bst build all flags

[Tristan Van Berkom <tristan vanberkom codethink co uk>]

Hi,

On Mon, 2018-12-03 at 16:06 +0100, Jürg Billeter wrote:
[...]
> I don't think it's bad if `bst [command]` builds the default project
> target when running `bst` in the project directory and the same command
> building the workspace element when running `bst` in the workspace
> directory. That's not that far off from `make` building the default
> goal/target of the Makefile in the current directory.
>
> I.e., my preference is `bst [command]` despite the concern you raised.

I do not expect we can ever guarantee a project where every element is
able to build with every possible configuration of options.

The assertion "(!)" directive exists explicitly for certain YAML
fragments inside the project to fire an informative error in the case
that that YAML fragment is invalid for the current configuration.

By this logic, there is no way to "build all elements", and the
assumption that one can build all of the elements in a project under
the same project option selection is simply false.

For this reason, the only way forward which makes any sense is to have
an explicitly specified target element as Jürg suggests, probably with
a recommendation that this should be a stack element which captures as
much as possible under the default build configuration.

Cheers,
    -Tristan