anchor.diff:    users   = map (x: x.user  or "''") contents;
     groups  = map (x: x.group or "''") contents;
   
  -  closureInfo = pkgs.closureInfo { rootPaths = [ config.system.build.toplevel channelSources ]; };
  +  closureInfo = pkgs.closureInfo {
  +    rootPaths = [ config.system.build.toplevel ] ++ (lib.optional copyChannel channelSources);
  +  };
   
     blockSize = toString (4 * 1024); # ext4fs block size (not block device sector size)
   
  
positive.code:     chmod 755 "$TMPDIR"
      echo "running nixos-install..."
      nixos-install --root $root --no-bootloader --no-root-passwd \
        --system ${config.system.build.toplevel} --channel ${channelSources} --substituters ""
  
      diskImage=nixos.raw
  
  
negative.code: 
  , # Disk image format, one of qcow2, qcow2-compressed, vdi, vpc, raw.
    format ? "raw"
  
  , # Whether a nix channel based on the current source tree should be
    # made available inside the image. Useful for interactive use of nix
    # utils, but changes the hash of the image when the sources are
    # updated.
    copyChannel ? true
  }:
  
  assert partitionTableType == "legacy" || partitionTableType == "legacy+gpt" || partitionTableType == "efi" || partitionTableType == "hybrid" || partitionTableType == "none";
  