Reproducible Arch Linux builds

[networkException]

Currently binaries compiled for Arch Linux cannot get reproduced using their tooling. repro expects the build process to have taken place in a clean chroot environment.

Digging into extra-x86_64-build, which can be used to run the build process using a single command given PKGBUILD in a working directory with other files required for the build, reveals that makechrootpkg uses a wrapper around systemd-nspawn to prepare and build in the chroot.

I've experimented with build-pkg-arch using only preinstall dependencies to setup $BUILDROOT and let it install all other dependencies into a seperate $ARCH_ROOT which matches the requirements of makechrootpkg (run in build-recipe-arch) as a predefined chroot directory.

I'm not sure however if this is the best approach, as it forces the build process to use nspawn regardless of the build-vm.

I would be great to have some guidance on how this could be achived.

(See archlinux/archlinux-repro#104)

[mlschroe]

I think it could be done by using the official devtools as "build engine". As an example from the Fedora world, you can use the "mock" tool as build engine (see "build-recipe-mock").
In that case, OBS will prepare a ".build.binaries" directory containing all the arch packages needed for the build and the setup of the build environment is then done by the official build tool.