error when using special_args with file, so far only supported us…

…ing flakes

terraform/nix-build/nix-build.sh

@@ -4,31 +4,36 @@ set -efu
 declare file attribute nix_options special_args
 eval "$(jq -r '@sh "attribute=\(.attribute) file=\(.file) nix_options=\(.nix_options) special_args=\(.special_args)"')"
 options=$(echo "${nix_options}" | jq -r '.options | to_entries | map("--option \(.key) \(.value)") | join(" ")')
-if [[ -n ${file-} ]] && [[ -e ${file-} ]]; then
-  # shellcheck disable=SC2086
-  out=$(nix build --no-link --json $options -f "$file" "$attribute")
-else
-  # pass the args in a pure fashion by extending the original config
-  if [[ ${special_args-} != "{}" ]]; then
-    rest="$(echo "${attribute}" | cut -d "#" -f 2)"
-    # e.g. config_path=nixosConfigurations.aarch64-linux.myconfig
-    config_path="${rest%.config.*}"
-    # e.g. config_attribute=config.system.build.toplevel
-    config_attribute="config.${rest#*.config.}"
-
-    # grab flake nar from error message
-    flake_rel="$(echo "${attribute}" | cut -d "#" -f 1)"
-    # e.g. flake_rel="."
-    flake_dir="$(readlink -f "${flake_rel}")"
-    flake_nar="$(nix build --expr "builtins.getFlake ''git+file://${flake_dir}?narHash=sha256-0000000000000000000000000000000000000000000=''" 2>&1 | grep -Po "(?<=got ')sha256-[^']*(?=')")"
-    # substitute variables into the template
-    nix_expr="(builtins.getFlake ''file://${flake_dir}/flake.nix?narHash=${flake_nar}'').${config_path}.extendModules { specialArgs = builtins.fromJSON ''${special_args}''; }"
-    # inject `special_args` into nixos config's `specialArgs`
+if [[ ${special_args-} == "{}" ]]; then
+  # no special arguments, proceed as normal
+  if [[ -n ${file-} ]] && [[ -e ${file-} ]]; then
     # shellcheck disable=SC2086
-    out=$(nix build --no-link --json ${options} --expr "${nix_expr}" "${config_attribute}")
+    out=$(nix build --no-link --json $options -f "$file" "$attribute")
   else
     # shellcheck disable=SC2086
     out=$(nix build --no-link --json ${options} "$attribute")
   fi
+else
+  if [[ ${file-} != 'null' ]]; then
+    echo "special_args are currently only supported when using flakes!" >&2
+    exit 1
+  fi
+  # pass the args in a pure fashion by extending the original config
+  rest="$(echo "${attribute}" | cut -d "#" -f 2)"
+  # e.g. config_path=nixosConfigurations.aarch64-linux.myconfig
+  config_path="${rest%.config.*}"
+  # e.g. config_attribute=config.system.build.toplevel
+  config_attribute="config.${rest#*.config.}"
+
+  # grab flake nar from error message
+  flake_rel="$(echo "${attribute}" | cut -d "#" -f 1)"
+  # e.g. flake_rel="."
+  flake_dir="$(readlink -f "${flake_rel}")"
+  flake_nar="$(nix build --expr "builtins.getFlake ''git+file://${flake_dir}?narHash=sha256-0000000000000000000000000000000000000000000=''" 2>&1 | grep -Po "(?<=got ')sha256-[^']*(?=')")"
+  # substitute variables into the template
+  nix_expr="(builtins.getFlake ''file://${flake_dir}/flake.nix?narHash=${flake_nar}'').${config_path}.extendModules { specialArgs = builtins.fromJSON ''${special_args}''; }"
+  # inject `special_args` into nixos config's `specialArgs`
+  # shellcheck disable=SC2086
+  out=$(nix build --no-link --json ${options} --expr "${nix_expr}" "${config_attribute}")
 fi
 printf '%s' "$out" | jq -c '.[].outputs'