Update script version to 4.9 and enhance error handling

ubuntu-to-mint-convert-v3.sh

@@ -20,7 +20,7 @@ set -euo pipefail
 # =========================
 # Version
 # =========================
-SCRIPT_VERSION="4.8"
+SCRIPT_VERSION="4.9"
 
 # =========================
 # Globals / Defaults
@@ -58,6 +58,16 @@ SYSTEM_KEYRING="/usr/share/keyrings/linuxmint-repo.gpg"
 # Error handling
 ON_ERROR_BACKUP_HINT=""
 
+on_err() {
+  local rc=$?
+  local line="${BASH_LINENO[0]:-unknown}"
+  echo "ERROR: FAILED at line ${line} (exit ${rc})."
+  echo "ERROR: Command: ${BASH_COMMAND}"
+  [[ -n "${ON_ERROR_BACKUP_HINT:-}" ]] && echo "${ON_ERROR_BACKUP_HINT}"
+  exit "$rc"
+}
+trap on_err ERR
+
 # =========================
 # Pretty output
 # =========================
@@ -100,7 +110,7 @@ Usage (command-first):
   sudo bash $0 convert --i-accept-the-risk [options]
   sudo bash $0 rollback /root/ubuntu-to-mint-backup-YYYYMMDD-HHMMSS
 
-Usage (options-first ALSO supported in v${SCRIPT_VERSION}):
+Usage (options-first ALSO supported):
   sudo bash $0 [options] doctor
   sudo bash $0 [options] plan
   sudo bash $0 [options] convert --i-accept-the-risk
@@ -264,7 +274,7 @@ timeshift_snapshot_best_effort() {
 }
 
 # =========================
-# Mint repo key bootstrap (no keyservers)
+# Keyrings
 # =========================
 gpg_key_file_has_keyid() {
   local f="$1"
@@ -272,6 +282,16 @@ gpg_key_file_has_keyid() {
   gpg --batch --with-colons --show-keys "$f" 2>/dev/null | awk -F: '$1=="pub"||$1=="sub"{print toupper($5)}' | grep -qx "$(echo "$keyid" | tr '[:lower:]' '[:upper:]')"
 }
 
+ubuntu_archive_keyring_path() {
+  # Needed for plan mode temp APT root signature verification.
+  DEBIAN_FRONTEND=noninteractive apt-get install -y ubuntu-keyring >/dev/null 2>&1 || true
+  if [[ -r /usr/share/keyrings/ubuntu-archive-keyring.gpg ]]; then
+    echo "/usr/share/keyrings/ubuntu-archive-keyring.gpg"
+    return 0
+  fi
+  die "Ubuntu archive keyring not found at /usr/share/keyrings/ubuntu-archive-keyring.gpg (install ubuntu-keyring?)"
+}
+
 mint_keyring_build_from_linuxmint_keyring_deb() {
   local out_keyring="$1"
   [[ -n "$out_keyring" ]] || die "mint_keyring_build_from_linuxmint_keyring_deb: missing output path"
@@ -346,7 +366,7 @@ mint_keyring_build_from_linuxmint_keyring_deb() {
   info "Using key candidate: $chosen"
   if [[ "$chosen" == *.asc || "$chosen" == *.key ]]; then
     grep -q "BEGIN PGP PUBLIC KEY BLOCK" "$chosen" 2>/dev/null || { rm -rf "$tmpdir"; die "Selected key candidate is not armored PGP: $chosen"; }
-    gpg --batch --dearmor -o "$tmp_out" "$chosen" || { rm -rf "$tmpdir"; die "gpg dearmor failed for key candidate"; }
+    gpg --batch --dearmor -o "$tmp_out" "$chosen"
   else
     cp -a "$chosen" "$tmp_out"
   fi
@@ -408,7 +428,9 @@ detect_ubuntu_mirrors() {
 
 write_mint_sources_system() {
   local list="/etc/apt/sources.list.d/official-package-repositories.list"
-  local keyring="$SYSTEM_KEYRING"
+  local mint_keyring="$SYSTEM_KEYRING"
+  local ubuntu_keyring
+  ubuntu_keyring="$(ubuntu_archive_keyring_path)"
 
   detect_ubuntu_mirrors
 
@@ -418,13 +440,13 @@ write_mint_sources_system() {
 # Generated by ubuntu-to-mint-convert-v3.sh on $(date -Is)
 #
 # Linux Mint repository:
-deb [signed-by=${keyring}] ${MINT_MIRROR%/} ${TARGET_MINT} main upstream import backport
+deb [signed-by=${mint_keyring}] ${MINT_MIRROR%/} ${TARGET_MINT} main upstream import backport
 
 # Ubuntu base repositories:
-deb ${UBUNTU_ARCHIVE_MIRROR%/} ${UBUNTU_BASE} main restricted universe multiverse
+deb [signed-by=${ubuntu_keyring}] ${UBUNTU_ARCHIVE_MIRROR%/} ${UBUNTU_BASE} main restricted universe multiverse
-deb ${UBUNTU_ARCHIVE_MIRROR%/} ${UBUNTU_BASE}-updates main restricted universe multiverse
+deb [signed-by=${ubuntu_keyring}] ${UBUNTU_ARCHIVE_MIRROR%/} ${UBUNTU_BASE}-updates main restricted universe multiverse
-deb ${UBUNTU_ARCHIVE_MIRROR%/} ${UBUNTU_BASE}-backports main restricted universe multiverse
+deb [signed-by=${ubuntu_keyring}] ${UBUNTU_ARCHIVE_MIRROR%/} ${UBUNTU_BASE}-backports main restricted universe multiverse
-deb ${UBUNTU_SECURITY_MIRROR%/} ${UBUNTU_BASE}-security main restricted universe multiverse
+deb [signed-by=${ubuntu_keyring}] ${UBUNTU_SECURITY_MIRROR%/} ${UBUNTU_BASE}-security main restricted universe multiverse
 EOF
 
   if [[ -f /etc/apt/sources.list ]]; then
@@ -490,7 +512,6 @@ session_name_for_edition() {
 }
 
 ensure_lightdm_on_boot() {
-  # Make LightDM the default display manager and ensure graphical boot.
   if [[ ! -d /run/systemd/system ]]; then
     warn "systemd not detected; cannot enable LightDM on boot in this environment."
     return 0
@@ -498,33 +519,23 @@ ensure_lightdm_on_boot() {
 
   info "Ensuring LightDM starts on boot (graphical.target + default display manager)..."
 
-  # Unmask LightDM in case something previously masked it
   systemctl unmask lightdm >/dev/null 2>&1 || true
-
-  # Ensure the default DM marker is LightDM
   echo "/usr/sbin/lightdm" > /etc/X11/default-display-manager || true
 
-  # Debian/Ubuntu DM selection often uses update-alternatives
   if have_cmd update-alternatives; then
     update-alternatives --set x-display-manager /usr/sbin/lightdm >/dev/null 2>&1 || true
   fi
 
-  # Ensure graphical boot target
   systemctl set-default graphical.target >/dev/null 2>&1 || true
   systemctl enable graphical.target >/dev/null 2>&1 || true
-
-  # Enable LightDM for boot
   systemctl enable lightdm >/dev/null 2>&1 || true
 
-  # Prevent GDM from stealing the greeter
   if systemctl list-unit-files | awk '{print $1}' | grep -qx 'gdm3.service'; then
     systemctl disable --now gdm3 >/dev/null 2>&1 || true
     systemctl mask gdm3 >/dev/null 2>&1 || true
   fi
 
-  # Restart the active DM if we can
   systemctl restart lightdm >/dev/null 2>&1 || true
-
   ok "LightDM configured to start on boot."
 }
 
@@ -533,21 +544,11 @@ ensure_lightdm_defaults() {
   sess="$(session_name_for_edition)"
 
   info "Configuring LightDM defaults for edition=${EDITION} (session=${sess})"
-
   DEBIAN_FRONTEND=noninteractive apt-get install -y lightdm slick-greeter
 
-  # Keep Ubuntu's gdm3 installed (if present) but ensure it can't win.
-  if systemctl is-enabled gdm3 >/dev/null 2>&1; then
-    warn "Disabling gdm3 (keeping installed)."
-    systemctl disable --now gdm3 || true
-    systemctl mask gdm3 || true
-    if [[ -f /etc/gdm3/custom.conf ]]; then
-      sed -i 's/^[#[:space:]]*WaylandEnable=.*/WaylandEnable=false/' /etc/gdm3/custom.conf || true
-      grep -q '^WaylandEnable=' /etc/gdm3/custom.conf || echo 'WaylandEnable=false' >> /etc/gdm3/custom.conf
-    fi
-  fi
-
   mkdir -p /etc/lightdm/lightdm.conf.d
+
+  # Comment out any existing user-session settings (keep files)
   shopt -s nullglob
   for f in /etc/lightdm/lightdm.conf.d/*.conf; do
     [[ "$(basename "$f")" == "99-ubuntu2mint.conf" ]] && continue
@@ -596,9 +597,7 @@ EOF
     chmod 644 "$dmrc" || true
   done
 
-  # This is the baked-in boot behavior you asked for:
   ensure_lightdm_on_boot
-
   ok "LightDM defaults applied; default session set to ${sess}."
 }
 
@@ -621,8 +620,7 @@ apply_mintupdate_icon_diversion() {
 # Post-install sanity checks
 # =========================
 post_install_sanity() {
-  local out_file="$1"
+  local out_file="${1:-/tmp/post-convert-validation.txt}"
-  [[ -n "$out_file" ]] || out_file="/tmp/post-convert-validation.txt"
 
   {
     echo "Post-conversion validation ($(date -Is))"
@@ -650,7 +648,7 @@ post_install_sanity() {
 }
 
 # =========================
-# Plan mode (temp APT root)
+# Plan mode helpers
 # =========================
 apt_tmp_run() {
   local tmpapt="$1"; shift
@@ -665,6 +663,24 @@ apt_tmp_run() {
   apt-get "${extra[@]}" "$@"
 }
 
+plan_fix_tmpapt_perms() {
+  local tmpapt="$1"
+
+  # Allow _apt sandbox to traverse and write partial lists
+  chmod 755 "$tmpapt" || true
+  chmod 755 "$tmpapt"/{etc,usr,var} 2>/dev/null || true
+  chmod 755 "$tmpapt"/var/{lib,cache} 2>/dev/null || true
+  chmod 755 "$tmpapt"/var/lib/apt 2>/dev/null || true
+  chmod 755 "$tmpapt"/var/cache/apt 2>/dev/null || true
+
+  if id _apt >/dev/null 2>&1; then
+    chown -R _apt:root "$tmpapt/var/lib/apt/lists/partial" 2>/dev/null || true
+    chown -R _apt:root "$tmpapt/var/cache/apt/archives/partial" 2>/dev/null || true
+    chmod 755 "$tmpapt/var/lib/apt/lists/partial" 2>/dev/null || true
+    chmod 755 "$tmpapt/var/cache/apt/archives/partial" 2>/dev/null || true
+  fi
+}
+
 plan_mode() {
   need_root
   ensure_no_apt_locks
@@ -674,19 +690,29 @@ plan_mode() {
 
   local tmpapt
   tmpapt="$(mktemp -d)"
-  mkdir -p "${tmpapt}/etc/apt/sources.list.d" "${tmpapt}/etc/apt/preferences.d" "${tmpapt}/var/lib/apt/lists/partial" "${tmpapt}/var/cache/apt/archives/partial" "${tmpapt}/usr/share/keyrings"
+  mkdir -p "${tmpapt}/etc/apt/sources.list.d" \
+           "${tmpapt}/etc/apt/preferences.d" \
+           "${tmpapt}/var/lib/apt/lists/partial" \
+           "${tmpapt}/var/cache/apt/archives/partial" \
+           "${tmpapt}/usr/share/keyrings"
+
+  plan_fix_tmpapt_perms "$tmpapt"
 
   local tmp_keyring="${tmpapt}/usr/share/keyrings/linuxmint-repo.gpg"
   mint_keyring_build_from_linuxmint_keyring_deb "$tmp_keyring"
 
+  local ubuntu_keyring
+  ubuntu_keyring="$(ubuntu_archive_keyring_path)"
+
   detect_ubuntu_mirrors
 
   cat > "${tmpapt}/etc/apt/sources.list" <<EOF
 deb [signed-by=${tmp_keyring}] ${MINT_MIRROR%/} ${TARGET_MINT} main upstream import backport
-deb ${UBUNTU_ARCHIVE_MIRROR%/} ${UBUNTU_BASE} main restricted universe multiverse
+
-deb ${UBUNTU_ARCHIVE_MIRROR%/} ${UBUNTU_BASE}-updates main restricted universe multiverse
+deb [signed-by=${ubuntu_keyring}] ${UBUNTU_ARCHIVE_MIRROR%/} ${UBUNTU_BASE} main restricted universe multiverse
-deb ${UBUNTU_ARCHIVE_MIRROR%/} ${UBUNTU_BASE}-backports main restricted universe multiverse
+deb [signed-by=${ubuntu_keyring}] ${UBUNTU_ARCHIVE_MIRROR%/} ${UBUNTU_BASE}-updates main restricted universe multiverse
-deb ${UBUNTU_SECURITY_MIRROR%/} ${UBUNTU_BASE}-security main restricted universe multiverse
+deb [signed-by=${ubuntu_keyring}] ${UBUNTU_ARCHIVE_MIRROR%/} ${UBUNTU_BASE}-backports main restricted universe multiverse
+deb [signed-by=${ubuntu_keyring}] ${UBUNTU_SECURITY_MIRROR%/} ${UBUNTU_BASE}-security main restricted universe multiverse
 EOF
 
   cat > "${tmpapt}/etc/apt/preferences.d/50-linuxmint-conversion.pref" <<'EOF'
@@ -723,14 +749,14 @@ EOF
   local rc=${PIPESTATUS[0]}
   set -e
 
+  rm -rf "$tmpapt"
+
   if [[ $rc -ne 0 ]]; then
     warn "Plan simulation failed (exit $rc). Review: $plan_out"
-    rm -rf "$tmpapt"
     exit $rc
   fi
 
   ok "Plan completed successfully. Review: $plan_out"
-  rm -rf "$tmpapt"
 }
 
 # =========================
@@ -829,10 +855,6 @@ convert() {
   info "Reinstalling x11-common (fixes Xsession has_option issues)..."
   DEBIAN_FRONTEND=noninteractive apt-get $(apt_opts_common) install --reinstall x11-common || true
 
-  info "Ensuring GNOME RandR runtime libs present (best-effort)..."
-  DEBIAN_FRONTEND=noninteractive apt-get $(apt_opts_common) install \
-    libgnome-rr-4-2t64 libgnome-desktop-4-2t64 libgnome-bg-4-2t64 || true
-
   ensure_lightdm_defaults
 
   mkdir -p "$backup_dir"