`mkosi build` fails when /etc/pacman.conf on {SkeletonTrees,PackageManagerTrees}

[mati1210]

$ cat mkosi.conf
[Distribution]
Distribution=arch

$ cp /etc/pacman.conf mkosi.skeleton/etc/pacman.conf

$ mkosi build
‣ Removing output files…
‣ Building default image                                                                                                        
‣  Copying in package manager file trees…
‣  Copying in skeleton file trees…
‣  Installing Arch                    
error: config file /etc/pacman.d/mirrorlist could not be read: No such file or directory 
‣ "pacman --root /home/mat/.cache/mkosi-workspacepw5p87lr/root --logfile=/dev/null --cachedir /home/mat/.cache/mkosi-workspacepw5p87lr/cache/cache/pacman/pkg --hookdir /home/mat
/.cache/mkosi-workspacepw5p87lr/root/etc/pacman.d/hooks --arch x86_64 --color auto --noconfirm --sync --refresh --needed --assume-installed initramfs filesystem" returned non-ze
ro exit code 1.

If mirrorlist is also copied into mkosi.skeleton it fails with another missing file

error: could not open file: /etc/mtab: No such file or directory
error: could not determine filesystem mount points
error: failed to commit transaction (unexpected error)

this also happens on PackageManagerTrees, --debug output https://gist.github.com/mati1210/f1c851987bd2b9889dff71630365e825

i'm not sure if this is the right way to do this, but it worked before updating to v20

[DaanDeMeyer]

Please post the contents of your pacman.conf

[mati1210]

here! it's just the standard pacman.conf with a few NoExtracts to remove some files i don't need

the error also happens with the standard pacman.conf, though

$ bsdtar Oxf /var/cache/pacman/pkg/pacman-6.0.2-8-x86_64.pkg.tar.zst etc/pacman.conf >mkosi.skeleton/etc/pacman.conf

$ mkosi build
‣ Removing output files…
‣ Building default image
Create subvolume '/home/mat/.cache/mkosi-workspacej8uvm7k2/root'
‣  Copying in package manager file trees…
‣  Copying in skeleton file trees…
‣  Installing Arch
error: config file /etc/pacman.d/mirrorlist could not be read: No such file or directory
‣ "pacman --root /home/mat/.cache/mkosi-workspacej8uvm7k2/root --logfile=/dev/null --cachedir /home/mat/.cache/mkosi-workspacej8uvm7k2/cache/cache/pacman/pkg --hookdir /home/mat/.cache/mkosi-workspacej8uvm7k2/root/etc/pacman.d/hooks --arch x86_64 --color auto --noconfirm --sync --refresh --needed --assume-installed initramfs filesystem" returned non-zero exit code 1.

[DaanDeMeyer]

@mati1210 We do proper sandboxing of the build since v20, so it's expected that /etc/pacman.d/mirrorlist isn't accessible anymore by default. You'll need to add it to your package manager tree so it can be found. I'll look into the other error.

[DaanDeMeyer]

@mati1210 The other error was caused by CheckSpace. I just merged a fix for that. You'll still need to put /etc/pacman.d/mirrorlist in either a package manager or skeleton tree.