jq was in fact not available in base arch iso

README.md

@@ -15,7 +15,7 @@ After writing the [iso](https://archlinux.org/download/) file to a bootable medi
 Some helper:
 ```bash
 loadkeys be-latin1 #load the belgian keyboard keys
-
+curl -fLO https://git.jika.li/Jika/system-spec/archive/master.tar.gz
 ```
 
 ## Ansible replication

installer/patch-disk-config.sh

@@ -16,7 +16,10 @@ CFG_IN="user_config_base.json"
 CFG_OUT="user_config.json"
 MIN_GIB=80
 
-die() { echo "Error: $*" >&2; exit 1; }
+die() {
+  echo "Error: $*" >&2
+  exit 1
+}
 
 if [[ $# -ne 1 ]]; then
   echo "Usage: $0 <disk-device>"
@@ -33,36 +36,60 @@ DISK="$1"
 
 # Minimum size check (bytes)
 SIZE_BYTES="$(lsblk -dn -o SIZE -b "$DISK")"
-(( SIZE_BYTES >= MIN_GIB * 1024 * 1024 * 1024 )) || die "'$DISK' is smaller than ${MIN_GIB}GiB."
+((SIZE_BYTES >= MIN_GIB * 1024 * 1024 * 1024)) || die "'$DISK' is smaller than ${MIN_GIB}GiB."
+
+read -r BOOT_SIZE_UNIT BOOT_SIZE_VALUE ROOT_START_BYTES ROOT_SIZE_BYTES < <(
+python3 - "$DISK" "$SIZE_BYTES" "$CFG_IN" "$CFG_OUT" <<'PY'
+import json, sys
+
+disk = sys.argv[1]
+size_bytes = int(sys.argv[2])
+cfg_in = sys.argv[3]
+cfg_out = sys.argv[4]
+
+with open(cfg_in, "r", encoding="utf-8") as f:
+    cfg = json.load(f)
 
 # Sanity: ensure expected JSON structure exists
-jq -e '
-  .disk_config.device_modifications
-  | type == "array" and length >= 1
-  and (. [0].partitions | type == "array" and length >= 2)
-  and (. [0].partitions[1].start.value | type == "number")
-  and (. [0].partitions[1].size.value  | type == "number")
-' "$CFG_IN" >/dev/null || die "Unexpected JSON structure in $CFG_IN (cannot locate partitions[1].start/size)."
+try:
+    dm0 = cfg["disk_config"]["device_modifications"][0]
+    parts = dm0["partitions"]
+    if not (isinstance(parts, list) and len(parts) >= 2):
+        raise TypeError("partitions not length >= 2")
+
+    p0 = parts[0]
+    p1 = parts[1]
+
+    root_start = p1["start"]["value"]
+    if isinstance(root_start, float) and root_start.is_integer():
+        root_start = int(root_start)
+    if not isinstance(root_start, int):
+        raise TypeError(f"start.value not int: {root_start!r}")
+
+except Exception as e:
+    raise SystemExit(f"Unexpected JSON structure in {cfg_in}: {e}")
 
 # Compute "root = remaining space" in bytes based on the configured root partition start offset
-ROOT_START_BYTES="$(jq -r '.disk_config.device_modifications[0].partitions[1].start.value' "$CFG_IN")"
-[[ "$ROOT_START_BYTES" =~ ^[0-9]+$ ]] || die "Root start offset is not a number: $ROOT_START_BYTES"
-
-ROOT_SIZE_BYTES=$(( SIZE_BYTES - ROOT_START_BYTES ))
-(( ROOT_SIZE_BYTES > 0 )) || die "Computed root size is not positive. Disk may be smaller than the configured start offset."
+root_size = size_bytes - root_start
+if root_size <= 0:
+    raise SystemExit("Computed root size is not positive.")
 
 # Patch:
 # - set target disk
 # - set root partition size to fill to end of disk (bytes)
-jq --arg d "$DISK" --argjson root_size "$ROOT_SIZE_BYTES" '
-  .disk_config.device_modifications[0].device = $d
-  | .disk_config.device_modifications[0].partitions[1].size.unit = "B"
-  | .disk_config.device_modifications[0].partitions[1].size.value = $root_size
-' "$CFG_IN" > "$CFG_OUT"
+dm0["device"] = disk
+p1["size"]["unit"] = "B"
+p1["size"]["value"] = int(root_size)
+
+with open(cfg_out, "w", encoding="utf-8") as f:
+    json.dump(cfg, f, indent=4)
+    f.write("\n")
 
 # Report
-BOOT_SIZE_UNIT="$(jq -r '.disk_config.device_modifications[0].partitions[0].size.unit' "$CFG_OUT")"
-BOOT_SIZE_VALUE="$(jq -r '.disk_config.device_modifications[0].partitions[0].size.value' "$CFG_OUT")"
+boot = p0["size"]
+print(boot["unit"], boot["value"], p1["start"]["value"], p1["size"]["value"])
+PY
+)
 
 echo "Prepared archinstall config: $CFG_OUT"
 echo "  Disk         : $DISK"