Fix partition issue

test/partition-numbering-test.sh

@@ -0,0 +1,131 @@
+#!/bin/bash
+#
+# create_partition() must report the number parted actually assigned, never a
+# predicted one. The regression this pins: the configurator used to compute
+# "highest existing partition + 1", while parted fills the lowest free GPT
+# slot. Any disk whose numbering has a hole — what deleting a partition to
+# free space leaves behind — then had every later command (cryptsetup, mkfs,
+# mount) pointed at device nodes that did not exist, surfacing much later as
+# "protected mode: /mnt is not a mountpoint".
+#
+# parted operates on image files directly, so this needs no root, no loop
+# devices, and no real disk.
+
+set -uo pipefail
+
+ROOT=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")/.." && pwd)
+LIB="$ROOT/configs/airootfs/usr/share/omarchy-iso/disk-partitioning.sh"
+
+if ! command -v parted >/dev/null 2>&1; then
+  echo "SKIP: parted is not installed"
+  exit 0
+fi
+
+# shellcheck source=../configs/airootfs/usr/share/omarchy-iso/disk-partitioning.sh
+source "$LIB"
+
+WORK=$(mktemp -d)
+trap 'rm -rf "$WORK"' EXIT
+
+IMG="$WORK/disk.img"
+MIB=$((1024 * 1024))
+failures=0
+
+check() {
+  local label="$1" expected="$2" actual="$3"
+  if [[ $expected == "$actual" ]]; then
+    printf '  ok   %s\n' "$label"
+  else
+    printf '  FAIL %s: expected %s, got %s\n' "$label" "$expected" "$actual"
+    failures=$((failures + 1))
+  fi
+}
+
+# parted reports a partition's size inclusive of both endpoints, so it lands
+# one sector above (end - start). Same slack create_partition allows.
+check_size() {
+  local label="$1" want="$2" actual="${3:-0}" delta
+  delta=$((actual - want))
+  (( delta < 0 )) && delta=$((-delta))
+  if (( delta <= MIB )); then
+    printf '  ok   %s\n' "$label"
+  else
+    printf '  FAIL %s: expected ~%s, got %s\n' "$label" "$want" "$actual"
+    failures=$((failures + 1))
+  fi
+}
+
+# parted's end position is inclusive, so partitions laid back to back overlap
+# by a sector and are refused. Leave a MiB between them.
+mkpart_mib() {
+  parted --script "$IMG" mkpart "$1" "$2" "$(($3 * MIB))B" "$(($4 * MIB))B"
+}
+
+# A disk with holes: four partitions, then delete the middle two. Slots 2 and
+# 3 are free while the highest number in use is 4 — the shape of the reported
+# failure, where the user deleted a partition to make room.
+build_holey_disk() {
+  rm -f "$IMG"
+  truncate -s 4G "$IMG"
+  parted --script "$IMG" mklabel gpt
+  mkpart_mib one ext4 1 200
+  mkpart_mib two ext4 201 400
+  mkpart_mib three ext4 401 600
+  mkpart_mib four ext4 601 800
+  parted --script "$IMG" rm 2
+  parted --script "$IMG" rm 3
+  created_parts=()
+}
+
+echo "==> numbering on a disk with holes"
+build_holey_disk
+check "existing numbers" "1 4" "$(partition_numbers "$IMG" | sort | tr '\n' ' ' | sed 's/ $//')"
+
+create_partition "$IMG" "$((1000 * MIB))" "$((1200 * MIB))" fat32 OMARCHY_EFI
+check "create_partition succeeded (esp)" "0" "$?"
+esp_num="$created_partition_number"
+check "esp took the lowest free slot" "2" "$esp_num"
+
+# Starts a MiB past the ESP, the way run_partition_decide aligns ROOT_START_B
+# up from EFI_END_B + 1.
+create_partition "$IMG" "$((1201 * MIB))" "$((2000 * MIB))" btrfs OMARCHY_ROOT
+check "create_partition succeeded (root)" "0" "$?"
+root_num="$created_partition_number"
+check "root took the next free slot" "3" "$root_num"
+
+# The old prediction. If either of these ever matches again, the regression is
+# back: the highest number in use was 4, so the guess would have been 5 and 6.
+check "esp is not the predicted number" "not-5" "$([[ $esp_num == 5 ]] && echo 5 || echo not-5)"
+check "root is not the predicted number" "not-6" "$([[ $root_num == 6 ]] && echo 6 || echo not-6)"
+
+check "both creations tracked for rollback" "2 3" "${created_parts[*]}"
+check_size "esp size" "$((200 * MIB))" "$(partition_size_bytes "$IMG" "$esp_num")"
+check_size "root size" "$((799 * MIB))" "$(partition_size_bytes "$IMG" "$root_num")"
+
+echo "==> rollback reclaims only what this run created"
+rollback_created_parts "$IMG"
+check "created partitions removed" "1 4" "$(partition_numbers "$IMG" | sort | tr '\n' ' ' | sed 's/ $//')"
+check "rollback list cleared" "0" "${#created_parts[@]}"
+
+echo "==> numbering on a disk without holes"
+rm -f "$IMG"
+truncate -s 4G "$IMG"
+parted --script "$IMG" mklabel gpt
+mkpart_mib one ext4 1 200
+mkpart_mib two ext4 201 400
+created_parts=()
+
+create_partition "$IMG" "$((1000 * MIB))" "$((1200 * MIB))" fat32 OMARCHY_EFI
+check "appends when there is no hole" "3" "$created_partition_number"
+
+echo "==> a refused creation stays out of the rollback list"
+created_parts=()
+create_partition "$IMG" "$((100 * MIB))" "$((300 * MIB))" ext4 OVERLAP
+check "overlapping creation failed" "1" "$?"
+check "nothing tracked" "0" "${#created_parts[@]}"
+
+if (( failures > 0 )); then
+  printf '\n%d check(s) failed\n' "$failures"
+  exit 1
+fi
+printf '\nall checks passed\n'