[Buildroot] host-python-2.7 failure to build _hashlib

[Thomas Petazzoni]

Hello Vladimir,

On Tue, 28 Jan 2020 00:35:49 +0200
Vladimir Oltean <olteanv at gmail.com> wrote:

> Ok, but I have to ask: why is host-python even built at all? For one
> thing, BR2_PACKAGE_HOST_PYTHON is not set.
> But with "make graph-depends", I am able to see that host-python is
> dragged in by:
> - python itself, which I selected
> - host-python-setuptools (dragged in by python-lxml, which I selected)
> - host-nodejs (dragged in by nodejs, which I selected)

Right, host-python is a dependency of all those things indeed.

> Granted, I don't know much, but I'm baffled that:
> - None of the above 3 packages select BR2_PACKAGE_HOST_PYTHON in their Config.in

Because we don't enforce this for host packages. We do enforce it for
target packages (i.e a target package cannot be built if its Config.in
option is not enabled somehow). But we don't enforce it for host
packages.

For example, host-pkgconf has a visible Config.in option called
BR2_PACKAGE_HOST_PKGCONF. However, almost none of the packages that
depend on host-pkgconf have a select BR2_PACKAGE_HOST_PKGCONF.

> - The Makefile doesn't complain that they don't (usually it does, when
> packages add _DEPENDENCIES that are absent from Config.in)

See above: only for target packages.

> When I enable BR2_PACKAGE_HOST_PYTHON and BR2_PACKAGE_HOST_PYTHON_SSL
> in .config, I am able to carry on with the build.
> 
> Can somebody please explain what is going on?
> I am not a proficient Python user either, by the way.

I don't really understand why your host-python package fails to build.
Could you share the entire build log of the host-python package ?

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com