Arch Linux

Summary and Info:
The title is a bit too specific as this regards any mask that removes folder access to others, and (probably) all build scripts.
These helper scripts will create /var/lib/archbuild/{repo}-{arch} with root's current umask, which can prevent current user from accessing those folders. Then the scripts will fails:

==> Building in chroot for [extra] (i686)...
==> Creating clean working copy [ambrevar]...done
==> ERROR: /var/lib/archbuild/extra-i686/ambrevar/etc/makepkg.conf not found.
Aborting...
==> ERROR: Could not download sources.


The process fails at mkarchroot:478:

download_sources() {
local builddir="$(mktemp -d)"
chmod 1777 "$builddir"

# Ensure sources are downloaded
if [[ -n $SUDO_USER ]]; then
sudo -u $SUDO_USER env SRCDEST="$SRCDEST" BUILDDIR="$builddir" \
makepkg --config="$copydir/etc/makepkg.conf" --verifysource -o


A possible fix would be to add 'umask 022' before creating the folder in the build scripts, i.e.

umask 022
mkdir -p "${chroots}/${repo}-${arch}"


Steps to Reproduce:
* Setup root session to use a umask 027 (or any mask that removes folder access to others).
* Remove /var/lib/archbuild if existing.
* Run `sudo extra-x86_64-build`,