diff --git a/migrations/1788380505.sh b/migrations/1788380505.sh
new file mode 100644
index 00000000000..9fb54e8b609
--- /dev/null
+++ b/migrations/1788380505.sh
@@ -0,0 +1,281 @@
+echo "Repair an existing SDDM Qt5 theme selection with missing greeter libraries"
+
+# This is a one-time repair, not a recurring theme-selection guard.
+# An existing theme with SddmGreeterTheme/QtVersion=5 (the default) selects
+# /usr/bin/sddm-greeter. If that executable lacks libraries, login stays black.
+# Missing themes or executables already fall back safely in SDDM itself.
+# Preserve working selections and replace only a confirmed broken Qt5 choice.
+
+sddm_conf="${OMARCHY_SDDM_CONF:-/etc/sddm.conf}"
+sddm_conf_dir="${OMARCHY_SDDM_CONF_DIR:-/etc/sddm.conf.d}"
+sys_conf_dir="${OMARCHY_SDDM_SYS_CONF_DIR:-/usr/lib/sddm/sddm.conf.d}"
+theme_dir="${OMARCHY_SDDM_THEME_DIR:-/usr/share/sddm/themes}"
+qt5_greeter="${OMARCHY_SDDM_QT5_GREETER:-/usr/bin/sddm-greeter}"
+qt6_greeter="${OMARCHY_SDDM_QT6_GREETER:-/usr/bin/sddm-greeter-qt6}"
+backup_dir="${OMARCHY_SDDM_BACKUP_DIR:-/var/lib/omarchy/sddm-backups}"
+proc_root="${OMARCHY_SDDM_PROC_ROOT:-/proc}"
+
+as_root() {
+  if (( EUID == 0 )); then
+    "$@"
+  else
+    sudo "$@"
+  fi
+}
+
+as_root python3 -I - "$sddm_conf" "$sddm_conf_dir" "$sys_conf_dir" "$theme_dir" "$qt5_greeter" "$qt6_greeter" "$backup_dir" "$proc_root" <<'PY'
+import ctypes
+import ctypes.util
+import io
+import os
+from pathlib import Path
+import re
+import stat
+import subprocess
+import sys
+import tempfile
+
+conf, conf_dir, sys_dir, themes, qt5, qt6, backups, proc_root = map(Path, sys.argv[1:])
+os.umask(0o077)
+os.chdir('/')
+
+
+def service_locale():
+  def main_pid():
+    result = subprocess.run(['systemctl', 'show', 'sddm.service', '--property=MainPID', '--value'],
+      stdout=subprocess.PIPE, stderr=subprocess.DEVNULL, text=True, timeout=5)
+    return result.stdout.strip() if result.returncode == 0 else ''
+  try:
+    pid = main_pid()
+    if not re.fullmatch(r'[1-9][0-9]*', pid):
+      return None
+    fd = os.open(proc_root / pid, os.O_RDONLY | os.O_DIRECTORY)
+    try:
+      if os.readlink('exe', dir_fd=fd).removesuffix(' (deleted)') != '/usr/bin/sddm':
+        return None
+      environment = {}
+      with os.fdopen(os.open('environ', os.O_RDONLY, dir_fd=fd), 'rb') as source:
+        for entry in source.read().split(b'\0'):
+          key, _, value = entry.partition(b'=')
+          if key in (b'LC_ALL', b'LC_COLLATE', b'LANG'):
+            environment[key] = value
+    finally:
+      os.close(fd)
+    if main_pid() == pid:
+      return (environment.get(b'LC_ALL') or environment.get(b'LC_COLLATE') or environment.get(b'LANG') or b'C').decode('ascii').split('.')[0]
+  except (OSError, ValueError, subprocess.TimeoutExpired):
+    return None
+
+
+# SDDM v0.21.0 ConfigReader.cpp loads vendor files, local files, then sddm.conf.
+# Match Qt's ICU collation, not libc sort order; the last [Theme] value wins.
+def directory_files(files):
+  language = service_locale()
+  if language is None:
+    raise RuntimeError('Cannot determine the running SDDM service locale for competing [Theme] settings; leaving SDDM unchanged')
+  if language in ('C', 'POSIX') or len(files) < 2:
+    return sorted(files, key=lambda p: p.name.encode('utf-16-be'))
+  library = ctypes.util.find_library('icui18n')
+  if not library:
+    raise RuntimeError('Cannot load Qt\'s ICU collator to resolve SDDM configuration order')
+  icu = ctypes.CDLL(library)
+  version = re.search(r'\.so\.(\d+)', library)
+  suffix = '_' + version[1] if version else ''
+  open_collator = getattr(icu, 'ucol_open' + suffix)
+  open_collator.argtypes, open_collator.restype = [ctypes.c_char_p, ctypes.POINTER(ctypes.c_int)], ctypes.c_void_p
+  sort_key = getattr(icu, 'ucol_getSortKey' + suffix)
+  sort_key.argtypes = [ctypes.c_void_p, ctypes.c_char_p, ctypes.c_int, ctypes.c_void_p, ctypes.c_int]
+  close_collator = getattr(icu, 'ucol_close' + suffix)
+  close_collator.argtypes, close_collator.restype = [ctypes.c_void_p], None
+  set_attribute = getattr(icu, 'ucol_setAttribute' + suffix)
+  set_attribute.argtypes = [ctypes.c_void_p, ctypes.c_int, ctypes.c_int, ctypes.POINTER(ctypes.c_int)]
+  set_attribute.restype = None
+  error = ctypes.c_int(0)
+  collator = open_collator(language.encode(), ctypes.byref(error))
+  if error.value > 0 or not collator:
+    raise RuntimeError(f'Cannot initialize the ICU collator for {language}')
+  def key(path):
+    name = path.name.encode('utf-16-le' if sys.byteorder == 'little' else 'utf-16-be')
+    length = sort_key(collator, name, len(name) // 2, None, 0)
+    buffer = ctypes.create_string_buffer(length)
+    sort_key(collator, name, len(name) // 2, buffer, length)
+    return buffer.raw
+  try:
+    NORMALIZATION, STRENGTH, NUMERIC, ALTERNATE = 4, 5, 7, 1
+    ON, TERTIARY, OFF, NON_IGNORABLE = 17, 2, 16, 21
+    for attribute, value in ((NORMALIZATION, ON), (STRENGTH, TERTIARY), (NUMERIC, OFF), (ALTERNATE, NON_IGNORABLE)):
+      set_attribute(collator, attribute, value, ctypes.byref(error))
+    if error.value > 0:
+      raise RuntimeError('Cannot configure the ICU collator to match Qt')
+    keys = {path: key(path) for path in files}
+    if len(set(keys.values())) != len(keys):
+      raise RuntimeError('SDDM configuration filenames have ambiguous ICU ordering; leaving SDDM unchanged')
+    return sorted(files, key=keys.__getitem__)
+  finally:
+    close_collator(collator)
+
+
+def configuration():
+  groups = [[p for p in directory.iterdir() if not p.name.startswith('.') and p.is_file()]
+    if directory.exists() else [] for directory in (sys_dir, conf_dir)]
+  groups.append([conf] if conf.exists() else [])
+  values = {'Current': '', 'ThemeDir': str(themes)}
+  contents, assignments, resolved = {}, {}, {}
+  active = None
+  for path in (p for group in groups for p in group):
+    contents[path] = path.read_bytes()
+    assignments[path] = {}
+    section = 'General'
+    for number, raw in enumerate(io.StringIO(contents[path].decode('utf-8'))):
+      line = raw.split('#', 1)[0].strip()
+      if '=' in line:
+        key, value = (part.strip() for part in line.split('=', 1))
+        if section == 'Theme' and key in values:
+          assignments[path][key] = (value, number)
+      elif line.startswith('[') and line.endswith(']'):
+        section = line[1:-1]
+  for group in reversed(groups):
+    ordered = None
+    for key in values.keys() - resolved.keys():
+      choices = [p for p in group if key in assignments[p]]
+      if not choices:
+        continue
+      if len({assignments[p][key][0] for p in choices}) > 1:
+        if ordered is None:
+          ordered = directory_files(group)
+        choices = [next(p for p in reversed(ordered) if key in assignments[p])]
+      path = choices[0]
+      resolved[key], number = assignments[path][key]
+      if key == 'Current' and len(choices) == 1:
+        active = (path, number)
+  values.update(resolved)
+  return values, contents, active
+
+
+def qt_version(theme):
+  path = theme / 'metadata.desktop'
+  if not path.exists():
+    return 5
+  section, version = '', '5'
+  for raw in re.split(r'\r\n|\r|\n', path.read_text(encoding='utf-8-sig')):
+    line = raw.strip()
+    if not line or line.startswith(('#', ';')):
+      continue
+    if '\\' in line:
+      raise RuntimeError(f'Cannot safely interpret escaped SDDM metadata: {path}')
+    quoted = False
+    for offset, character in enumerate(line):
+      if character == '"':
+        quoted = not quoted
+      elif character == ';' and not quoted:
+        line = line[:offset].strip()
+        break
+    if quoted:
+      raise RuntimeError(f'Cannot safely interpret multiline SDDM metadata: {path}')
+    if line.startswith('['):
+      if not re.fullmatch(r'\[[^\[\]]+\]', line):
+        raise RuntimeError(f'Cannot safely interpret malformed SDDM metadata section: {path}')
+      section = line[1:-1].strip()
+      if section == 'General':
+        section = ''
+    elif '=' in line:
+      key, value = (part.strip() for part in line.split('=', 1))
+      key = re.sub(r'%U([\da-fA-F]{4})|%([\da-fA-F]{2})',
+        lambda match: chr(int(match[1] or match[2], 16)), '/'.join(filter(None, (section, key))))
+      if key == 'SddmGreeterTheme/QtVersion':
+        version = value.replace('"', '').strip()
+  if version.startswith('@'):
+    if not (version.startswith('@String(') and version.endswith(')')):
+      raise RuntimeError(f'Cannot safely interpret typed SDDM QtVersion metadata: {path}')
+    version = version[8:-1].strip()
+  return int(version) if re.fullmatch(r'[+-]?[0-9]+', version) else 0
+
+
+# Consume ldd completely: grep -q can cause SIGPIPE and invert a pipefail test.
+# Probe failures are errors, not evidence that the greeter is healthy.
+def missing_libraries(binary):
+  result = subprocess.run(['ldd', str(binary)], capture_output=True, text=True,
+    env=dict(os.environ, LC_ALL='C'))
+  if result.returncode:
+    raise RuntimeError(f'ldd failed for {binary} ({result.returncode}): {result.stderr.strip()}')
+  return re.search(r'=>\s+not found(?:\s|$)', result.stdout) is not None
+
+
+def trusted_path(path):
+  for part in (path, *path.parents):
+    if not part.exists() and not part.is_symlink():
+      continue
+    info = part.lstat()
+    sticky_parent = part != path and stat.S_ISDIR(info.st_mode) and info.st_mode & stat.S_ISVTX
+    if stat.S_ISLNK(info.st_mode) or info.st_uid not in (0, os.geteuid()) or (info.st_mode & 0o022 and not sticky_parent):
+      raise RuntimeError(f'Refusing an untrusted SDDM repair path: {part}')
+
+
+# Save recovery copies outside SDDM's loaded directories, without replacing any
+# prior backup. Publish only the effective assignment through an atomic rename.
+def repair():
+  if not os.access(qt5, os.X_OK):
+    return
+  values, contents, active = configuration()
+  name = values['Current']
+  selected = Path(values['ThemeDir']) / name
+  if not name or not selected.exists() or qt_version(selected) != 5:
+    return
+  if not missing_libraries(qt5):
+    return
+  replacement = themes / 'omarchy'
+  if not replacement.is_dir() or qt_version(replacement) != 6 or not os.access(qt6, os.X_OK) or missing_libraries(qt6):
+    raise RuntimeError('The packaged Omarchy Qt6 greeter is not a safe replacement; leaving SDDM unchanged')
+  replacement_name = 'omarchy' if Path(values['ThemeDir']) == themes else str(replacement.absolute())
+  source, number = active if active else (None, None)
+  target = source if source and (source == conf or (source.parent == conf_dir and source.suffix == '.conf')) else conf
+  trusted_path(target)
+  trusted_path(backups)
+  if any(backups.resolve().is_relative_to(directory.resolve()) for directory in (sys_dir, conf_dir)):
+    raise RuntimeError('SDDM recovery backups must be outside its loaded configuration directories')
+  original = contents.get(target, b'')
+  info = target.lstat() if target.exists() else None
+  if info and (not stat.S_ISREG(info.st_mode) or info.st_nlink != 1):
+    raise RuntimeError(f'Refusing to replace a non-regular or hard-linked SDDM configuration: {target}')
+  if target == source:
+    lines = list(io.StringIO(original.decode('utf-8')))
+    line = lines[number]
+    prefix = re.match(r'\s*Current\s*=\s*', line).group()
+    end = len(line.split('#', 1)[0].rstrip())
+    lines[number] = prefix + replacement_name + line[end:]
+    updated = ''.join(lines).encode('utf-8')
+  else:
+    updated = original + (b'\n' if original and not original.endswith(b'\n') else b'')
+    updated += f'[Theme]\nCurrent={replacement_name}\n'.encode('utf-8')
+  if configuration() != (values, contents, active):
+    raise RuntimeError('SDDM configuration changed during the repair; retry the migration')
+  if info:
+    backups.mkdir(mode=0o700, parents=True, exist_ok=True)
+    backup = Path(tempfile.mkdtemp(prefix='1788380505-', dir=backups)) / target.name
+    with backup.open('xb') as output:
+      output.write(original)
+      output.flush()
+      os.fsync(output.fileno())
+    print(f'Saved SDDM recovery copy: {backup}', flush=True)
+  fd, temporary = tempfile.mkstemp(prefix='.omarchy-sddm-', dir=target.parent)
+  try:
+    with os.fdopen(fd, 'wb') as output:
+      output.write(updated)
+      if info:
+        os.fchown(output.fileno(), info.st_uid, info.st_gid)
+      os.fchmod(output.fileno(), stat.S_IMODE(info.st_mode) if info else 0o644)
+      output.flush()
+      os.fsync(output.fileno())
+    os.replace(temporary, target)
+  finally:
+    if os.path.exists(temporary):
+      os.unlink(temporary)
+  print(f"Reset SDDM theme from '{name}' to '{replacement_name}' because the Qt5 greeter has missing libraries.")
+
+
+try:
+  repair()
+except (OSError, ValueError, RuntimeError, AttributeError) as error:
+  print(f'SDDM theme repair failed: {error}', file=sys.stderr)
+  sys.exit(1)
+PY
diff --git a/test/shell.d/sddm-qt6-guard-test.sh b/test/shell.d/sddm-qt6-guard-test.sh
new file mode 100644
index 00000000000..3dedc9fdb9c
--- /dev/null
+++ b/test/shell.d/sddm-qt6-guard-test.sh
@@ -0,0 +1,605 @@
+#!/bin/bash
+
+set -euo pipefail
+
+source "$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)/base-test.sh"
+
+migration="$ROOT/migrations/1788380505.sh"
+[[ -f $migration ]] || fail "SDDM Qt6 guard migration exists"
+
+test_dir=$(mktemp -d)
+trap 'rm -rf "$test_dir"' EXIT
+test_dir=$(cd -- "$test_dir" && pwd -P)
+
+mkdir -p "$test_dir/bin" "$test_dir/etc/sddm.conf.d" "$test_dir/usr/share/sddm/themes/"{omarchy,maya,custom6} "$test_dir/usr/bin" "$test_dir/proc/23456"
+printf 'LC_ALL=C\0' >"$test_dir/proc/23456/environ"
+ln -s /usr/bin/sddm "$test_dir/proc/23456/exe"
+
+cat >"$test_dir/bin/systemctl" <<'STUB'
+#!/bin/bash
+printf '23456\n'
+STUB
+chmod +x "$test_dir/bin/systemctl"
+
+cat >"$test_dir/bin/sudo" <<'STUB'
+#!/bin/bash
+exec "$@"
+STUB
+chmod +x "$test_dir/bin/sudo"
+
+cat >"$test_dir/bin/ldd" <<'STUB'
+#!/bin/bash
+# Fake ldd: prints missing-library lines when the binary name contains -broken.
+if [[ ${1##*/} == *-broken* ]]; then
+  printf 'libQt5Core.so.5 => not found\nlibQt5Gui.so.5 => not found\n'
+fi
+STUB
+chmod +x "$test_dir/bin/ldd"
+
+cat >"$test_dir/usr/share/sddm/themes/omarchy/metadata.desktop" <<'EOF'
+[SddmGreeterTheme]
+Name=Omarchy
+QtVersion=6
+EOF
+
+cat >"$test_dir/usr/share/sddm/themes/maya/metadata.desktop" <<'EOF'
+[SddmGreeterTheme]
+Name=Maya
+EOF
+
+cat >"$test_dir/usr/share/sddm/themes/custom6/metadata.desktop" <<'EOF'
+[SddmGreeterTheme]
+Name=Custom
+QtVersion=6
+EOF
+
+touch "$test_dir/usr/bin/sddm-greeter-good"
+touch "$test_dir/usr/bin/sddm-greeter-broken"
+touch "$test_dir/usr/bin/sddm-greeter-qt6"
+chmod +x "$test_dir/usr/bin/"sddm-greeter-*
+
+run_migration() {
+  HOME="$test_dir/home" \
+    OMARCHY_SDDM_CONF="$test_dir/etc/sddm.conf" \
+    OMARCHY_SDDM_CONF_DIR="$test_dir/etc/sddm.conf.d" \
+    OMARCHY_SDDM_SYS_CONF_DIR="$test_dir/usr/lib/sddm/sddm.conf.d" \
+    OMARCHY_SDDM_PROC_ROOT="$test_dir/proc" \
+    OMARCHY_SDDM_BACKUP_DIR="$test_dir/backups" \
+    OMARCHY_SDDM_THEME_DIR="$test_dir/usr/share/sddm/themes" \
+    OMARCHY_SDDM_QT5_GREETER="$test_dir/usr/bin/$1" \
+    OMARCHY_SDDM_QT6_GREETER="$test_dir/usr/bin/sddm-greeter-qt6" \
+    PATH="$test_dir/bin:$PATH" \
+    bash -euo pipefail "$migration"
+}
+
+# Scenario 1: the active theme already declares QtVersion=6 — no change.
+{
+  reset_state() {
+    rm -rf "$test_dir/etc" "$test_dir/home"
+    mkdir -p "$test_dir/etc/sddm.conf.d" "$test_dir/home"
+  }
+  reset_state
+  printf '[Theme]\nCurrent=omarchy\n' >"$test_dir/etc/sddm.conf.d/10-theme.conf"
+  run_migration sddm-greeter-broken >/dev/null
+  grep -Fx 'Current=omarchy' "$test_dir/etc/sddm.conf.d/10-theme.conf" >/dev/null ||
+    fail "safe Qt6 theme is left unchanged"
+}
+
+# Scenario 2: an existing Qt5 theme is active with missing greeter libraries — reset.
+{
+  reset_state
+  printf '[Theme]\nCurrent=omarchy\n' >"$test_dir/etc/sddm.conf.d/10-theme.conf"
+  printf '[Theme]\nCurrent=maya\n' >"$test_dir/etc/sddm.conf.d/99-user-theme.conf"
+  run_migration sddm-greeter-broken >/dev/null
+  grep -Fx 'Current=omarchy' "$test_dir/etc/sddm.conf.d/99-user-theme.conf" >/dev/null ||
+    fail "unsafe non-Qt6 theme is reset to omarchy"
+  grep -Fx 'Current=omarchy' "$test_dir/etc/sddm.conf.d/10-theme.conf" >/dev/null ||
+    fail "packaged theme file stays valid"
+}
+
+# Scenario 3: a Qt5 theme is active but its greeter links successfully — leave it.
+{
+  reset_state
+  printf '[Theme]\nCurrent=maya\n' >"$test_dir/etc/sddm.conf.d/10-theme.conf"
+  run_migration sddm-greeter-good >/dev/null
+  grep -Fx 'Current=maya' "$test_dir/etc/sddm.conf.d/10-theme.conf" >/dev/null ||
+    fail "non-Qt6 theme is left alone when Qt5 greeter works"
+}
+
+# Scenario 4: a custom theme declares QtVersion=6 even though the Qt5 greeter is broken.
+{
+  reset_state
+  printf '[Theme]\nCurrent=custom6\n' >"$test_dir/etc/sddm.conf.d/10-theme.conf"
+  run_migration sddm-greeter-broken >/dev/null
+  grep -Fx 'Current=custom6' "$test_dir/etc/sddm.conf.d/10-theme.conf" >/dev/null ||
+    fail "custom Qt6 theme is left unchanged"
+}
+
+# Scenario 5: no Current= is configured anywhere — nothing to guard.
+{
+  reset_state
+  run_migration sddm-greeter-broken >/dev/null
+  [[ ! -e $test_dir/etc/sddm.conf.d/10-theme.conf ]] ||
+    fail "guard does not create a theme file when none exists"
+}
+
+pass "SDDM Qt6 theme guard resets unsafe themes and preserves safe ones"
+
+python3 - "$migration" <<'PY'
+import os
+from pathlib import Path
+import subprocess
+import sys
+import tempfile
+import unittest
+
+migration = sys.argv.pop()
+
+
+class SddmRepairTest(unittest.TestCase):
+  def setUp(self):
+    self.scratch = tempfile.TemporaryDirectory()
+    self.addCleanup(self.scratch.cleanup)
+    self.root = Path(self.scratch.name).resolve()
+    for directory in ('etc/sddm.conf.d', 'vendor', 'bin', 'home', 'backups'):
+      (self.root / directory).mkdir(parents=True)
+    self.env = dict(os.environ, HOME=str(self.root / 'home'), LC_ALL='C',
+      OMARCHY_SDDM_CONF=str(self.root / 'etc/sddm.conf'),
+      OMARCHY_SDDM_CONF_DIR=str(self.root / 'etc/sddm.conf.d'),
+      OMARCHY_SDDM_SYS_CONF_DIR=str(self.root / 'vendor'),
+      OMARCHY_SDDM_PROC_ROOT=str(self.root / 'proc'),
+      OMARCHY_SDDM_THEME_DIR=str(self.root / 'themes'),
+      OMARCHY_SDDM_BACKUP_DIR=str(self.root / 'backups'),
+      OMARCHY_SDDM_QT5_GREETER=str(self.root / 'bin/greeter5'),
+      OMARCHY_SDDM_QT6_GREETER=str(self.root / 'bin/greeter6'),
+      PATH=str(self.root / 'bin') + ':' + os.environ['PATH'])
+    for name in ('greeter5', 'greeter6'):
+      self.put('bin/' + name, '')
+      (self.root / 'bin' / name).chmod(0o755)
+    self.put('bin/ldd', '\n'.join((
+      '#!/bin/bash',
+      'if [[ $1 == *greeter5 ]]; then',
+      '  case ${SDDM_TEST_LDD:-broken} in',
+      "    good) printf 'libQt5Core.so.5 => /usr/lib/libQt5Core.so.5\\n' ;;",
+      "    error) echo 'ldd: failed to inspect greeter' >&2; exit 42 ;;",
+      "    changed) printf '# administrator edit\\n' >>\"$OMARCHY_SDDM_CONF_DIR/10-theme.conf\"; printf 'libQt5Core.so.5 => not found\\n' ;;",
+      "    large) printf 'libQt5Core.so.5 => not found\\n'; for ((i=0; i<10000; i++)); do printf 'libother.so => /usr/lib/libother.so\\n'; done ;;",
+      "    *) printf 'libQt5Core.so.5 => not found\\n' ;;",
+      '  esac',
+      "elif [[ ${SDDM_TEST_QT6_BROKEN:-0} == 1 ]]; then",
+      "  printf 'libQt6Core.so.6 => not found\\n'",
+      'fi',
+      '')))
+    (self.root / 'bin/ldd').chmod(0o755)
+    self.put('bin/sudo', '#!/bin/bash\nexec "$@"\n')
+    (self.root / 'bin/sudo').chmod(0o755)
+    self.put('bin/systemctl', '\n'.join((
+      '#!/bin/bash',
+      '[[ $* == "show sddm.service --property=MainPID --value" ]] || exit 2',
+      'touch "$OMARCHY_SDDM_PROC_ROOT/queried"',
+      'printf "%s\\n" "${SDDM_TEST_MAIN_PID:-23456}"',
+      'exit "${SDDM_TEST_SYSTEMCTL_STATUS:-0}"',
+      ''))).chmod(0o755)
+    self.put('proc/23456/environ', 'LC_ALL=C\0')
+    (self.root / 'proc/23456/exe').symlink_to('/usr/bin/sddm')
+    for theme, metadata in {'omarchy': 'QtVersion=6', 'maya': 'Name=Maya', 'custom6': 'QtVersion=6'}.items():
+      self.put('themes/' + theme + '/metadata.desktop', '[SddmGreeterTheme]\n' + metadata + '\n')
+    self.dropin = 'etc/sddm.conf.d/10-theme.conf'
+
+  def put(self, path, text):
+    dest = self.root / path
+    dest.parent.mkdir(parents=True, exist_ok=True)
+    dest.write_bytes(text.encode())
+    return dest
+
+  def get(self, path):
+    return (self.root / path).read_bytes().decode()
+
+  def run_repair(self, success=True):
+    result = subprocess.run(['bash', '-euo', 'pipefail', migration], env=self.env, cwd=self.root / 'home', capture_output=True, text=True)
+    if success:
+      self.assertEqual(result.returncode, 0, result.stdout + result.stderr)
+    else:
+      self.assertNotEqual(result.returncode, 0, result.stdout + result.stderr)
+    return result
+
+  def snapshot(self):
+    return {str(p.relative_to(self.root)): p.read_bytes() for directory in ('etc', 'vendor', 'backups')
+      for p in (self.root / directory).rglob('*') if p.is_file()}
+
+  def assert_unchanged(self, success=True):
+    before = self.snapshot()
+    self.run_repair(success)
+    self.assertEqual(self.snapshot(), before)
+
+  def backups(self):
+    return [p for p in (self.root / 'backups').rglob('*') if p.is_file()]
+
+  def test_etc_conf_has_highest_precedence(self):
+    self.put(self.dropin, '[Theme]\nCurrent=omarchy\n')
+    self.put('etc/sddm.conf', '[Theme]\nCurrent=maya\n')
+    self.run_repair()
+    self.assertEqual(self.get('etc/sddm.conf'), '[Theme]\nCurrent=omarchy\n')
+    self.assertEqual(self.get(self.dropin), '[Theme]\nCurrent=omarchy\n')
+
+  @unittest.skipUnless(sys.platform.startswith('linux'), 'Linux ICU sorting')
+  def test_locale_aware_directory_order_matches_qt_icu(self):
+    for environment in ('LANG=en_US.UTF-8\0', 'LANG=C\0LC_COLLATE=en_US.UTF-8\0',
+                        'LANG=C\0LC_COLLATE=C\0LC_ALL=en_US.UTF-8\0'):
+      with self.subTest(environment=environment):
+        self.put('proc/23456/environ', environment + 'PRIVATE=do-not-print-this\0')
+        self.put('etc/sddm.conf.d/a.conf', '[Theme]\nCurrent=maya\n')
+        self.put('etc/sddm.conf.d/a_.conf', '[Theme]\nCurrent=custom6\n')
+        result = self.run_repair()
+        self.assertNotIn('do-not-print-this', result.stdout + result.stderr)
+        self.assertEqual(self.get('etc/sddm.conf.d/a.conf'), '[Theme]\nCurrent=omarchy\n')
+        self.assertEqual(self.get('etc/sddm.conf.d/a_.conf'), '[Theme]\nCurrent=custom6\n')
+
+  @unittest.skipUnless(sys.platform.startswith('linux'), 'Linux ICU sorting')
+  def test_equal_icu_keys_are_not_given_a_guessed_order(self):
+    self.put('proc/23456/environ', 'LC_ALL=en_US.UTF-8\0')
+    for i in range(20):
+      self.put('etc/sddm.conf.d/a' + '\u200d' * i + '.conf', '[Theme]\nCurrent=' + ('maya' if i else 'custom6') + '\n')
+    before = self.snapshot()
+    result = self.run_repair(success=False)
+    self.assertIn('ambiguous', result.stderr)
+    self.assertEqual(self.snapshot(), before)
+
+  def test_service_c_locale_overrides_updater_locale(self):
+    self.env['LC_ALL'] = 'en_US.UTF-8'
+    self.put('etc/sddm.conf.d/a.conf', '[Theme]\nCurrent=maya\n')
+    self.put('etc/sddm.conf.d/a_.conf', '[Theme]\nCurrent=custom6\n')
+    for environment in ('', 'LANG=\0LC_ALL=\0', 'LANG=en_US.UTF-8\0LC_COLLATE=C\0',
+                        'LANG=en_US.UTF-8\0LC_COLLATE=en_US.UTF-8\0LC_ALL=C\0'):
+      with self.subTest(environment=environment):
+        self.put('proc/23456/environ', environment)
+        self.assert_unchanged()
+
+  def test_unavailable_service_locale_does_not_guess_competing_settings(self):
+    self.put('etc/sddm.conf.d/a.conf', '[Theme]\nCurrent=maya\n')
+    self.put('etc/sddm.conf.d/a_.conf', '[Theme]\nCurrent=custom6\n')
+    for pid in ('0', 'not-a-pid', '99999', '../23456'):
+      with self.subTest(pid=pid):
+        self.env['SDDM_TEST_MAIN_PID'] = pid
+        before = self.snapshot()
+        result = self.run_repair(success=False)
+        self.assertIn('service locale', result.stderr)
+        self.assertEqual(self.snapshot(), before)
+    self.env['SDDM_TEST_MAIN_PID'] = '23456'
+    self.env['SDDM_TEST_SYSTEMCTL_STATUS'] = '1'
+    self.assert_unchanged(success=False)
+    self.env['SDDM_TEST_SYSTEMCTL_STATUS'] = '0'
+    (self.root / 'proc/23456/environ').unlink()
+    self.assert_unchanged(success=False)
+
+  def test_service_locale_is_not_taken_from_another_executable(self):
+    self.put('etc/sddm.conf.d/a.conf', '[Theme]\nCurrent=maya\n')
+    self.put('etc/sddm.conf.d/a_.conf', '[Theme]\nCurrent=custom6\n')
+    executable = self.root / 'proc/23456/exe'
+    executable.unlink()
+    executable.symlink_to('/usr/bin/user-session')
+    self.assert_unchanged(success=False)
+    executable.unlink()
+    executable.symlink_to('/usr/bin/sddm (deleted)')
+    self.assert_unchanged()
+
+  def test_service_pid_change_during_locale_read_stays_pending(self):
+    self.put('bin/systemctl', '\n'.join((
+      '#!/bin/bash',
+      'if [[ -e $OMARCHY_SDDM_PROC_ROOT/queried ]]; then',
+      "  printf '0\\n'",
+      'else',
+      '  touch "$OMARCHY_SDDM_PROC_ROOT/queried"',
+      "  printf '23456\\n'",
+      'fi',
+      ''))).chmod(0o755)
+    self.put('etc/sddm.conf.d/a.conf', '[Theme]\nCurrent=maya\n')
+    self.put('etc/sddm.conf.d/a_.conf', '[Theme]\nCurrent=custom6\n')
+    self.assert_unchanged(success=False)
+
+  def test_stopped_service_allows_unambiguous_settings_and_higher_overrides(self):
+    self.env['SDDM_TEST_MAIN_PID'] = '0'
+    self.env['LC_ALL'] = 'not-a-locale'
+    self.put('vendor/default.conf', '[Theme]\nCurrent=maya\n')
+    self.put('etc/sddm.conf.d/a.conf', '[Theme]\nCurrent=custom6\n')
+    self.put('etc/sddm.conf.d/a_.conf', '[Theme]\nCurrent=custom6\n[Users]\nHideUsers=private\n')
+    self.assert_unchanged()
+    self.put('etc/sddm.conf.d/a.conf', '[Theme]\nCurrent=maya\n')
+    self.put('etc/sddm.conf', '[Theme]\nCurrent=custom6\n')
+    self.assert_unchanged()
+    self.put('etc/sddm.conf', '[Theme]\nCurrent=maya\n')
+    self.run_repair()
+    self.assertEqual(self.get('etc/sddm.conf'), '[Theme]\nCurrent=omarchy\n')
+    self.assertFalse((self.root / 'proc/queried').exists())
+
+  def test_stopped_service_same_broken_choice_gets_an_override(self):
+    self.env['SDDM_TEST_MAIN_PID'] = '0'
+    for name in ('a.conf', 'a_.conf'):
+      self.put('etc/sddm.conf.d/' + name, '[Theme]\nCurrent=maya\n')
+    self.run_repair()
+    self.assertEqual(self.get('etc/sddm.conf'), '[Theme]\nCurrent=omarchy\n')
+    for name in ('a.conf', 'a_.conf'):
+      self.assertEqual(self.get('etc/sddm.conf.d/' + name), '[Theme]\nCurrent=maya\n')
+
+  def test_stopped_service_does_not_guess_theme_directory(self):
+    self.env['SDDM_TEST_MAIN_PID'] = '0'
+    self.put(self.dropin, '[Theme]\nCurrent=custom6\n')
+    self.put('vendor/a.conf', '[Theme]\nThemeDir=/missing\n')
+    self.put('vendor/a_.conf', '[Theme]\nThemeDir=' + str(self.root / 'themes') + '\n')
+    self.assert_unchanged(success=False)
+    self.put('etc/sddm.conf', '[Theme]\nThemeDir=' + str(self.root / 'themes') + '\n')
+    self.assert_unchanged()
+
+  def test_missing_qt5_executable_needs_no_service_locale(self):
+    self.env['SDDM_TEST_MAIN_PID'] = '0'
+    self.put('etc/sddm.conf.d/a.conf', '[Theme]\nCurrent=maya\n')
+    self.put('etc/sddm.conf.d/a_.conf', '[Theme]\nCurrent=custom6\n')
+    (self.root / 'bin/greeter5').unlink()
+    self.assert_unchanged()
+
+  def test_metadata_escaped_group_and_quoted_semicolon_follow_qsettings(self):
+    for metadata in ('[%53ddmGreeterTheme]\nQtVersion=6\n',
+                     '[SddmGreeterTheme]\nQtVersion="5;not a number"\n'):
+      with self.subTest(metadata=metadata):
+        self.put('themes/custom6/metadata.desktop', metadata)
+        self.put(self.dropin, '[Theme]\nCurrent=custom6\n')
+        self.assert_unchanged()
+
+  def test_only_newline_delimits_sddm_config_records(self):
+    self.put(self.dropin, '[Theme]\nCurrent=custom6\vCurrent=maya\n')
+    self.assert_unchanged()
+
+  def test_safe_high_priority_config_does_not_modify_inactive_choices(self):
+    self.put(self.dropin, '[Theme]\nCurrent=maya\n')
+    self.put('etc/sddm.conf', '[Theme]\nCurrent=custom6\n')
+    self.assert_unchanged()
+
+  def test_all_visible_directory_files_participate(self):
+    for suffix in ('.pacsave', '.pacnew', '.bak', '~', '.txt'):
+      with self.subTest(suffix=suffix):
+        self.put(self.dropin, '[Theme]\nCurrent=omarchy\n')
+        path = self.dropin + suffix
+        self.put(path, '[Theme]\nCurrent=maya\n')
+        self.run_repair()
+        self.assertEqual(self.get(path), '[Theme]\nCurrent=maya\n')
+        self.assertEqual(self.get('etc/sddm.conf'), '[Theme]\nCurrent=omarchy\n')
+        (self.root / path).unlink()
+        (self.root / 'etc/sddm.conf').unlink()
+
+  def test_hidden_files_and_directories_are_not_loaded(self):
+    self.put(self.dropin, '[Theme]\nCurrent=custom6\n')
+    self.put('etc/sddm.conf.d/.hidden', '[Theme]\nCurrent=maya\n')
+    self.put('etc/sddm.conf.d/99-directory/file.conf', '[Theme]\nCurrent=maya\n')
+    self.assert_unchanged()
+
+  def test_vendor_theme_gets_local_override_not_package_edit(self):
+    self.put('vendor/default.conf', '[Theme]\nCurrent=maya\n')
+    self.put('etc/sddm.conf', '[Users]\nHideUsers=private')
+    self.run_repair()
+    self.assertEqual(self.get('vendor/default.conf'), '[Theme]\nCurrent=maya\n')
+    self.assertEqual(self.get('etc/sddm.conf'), '[Users]\nHideUsers=private\n[Theme]\nCurrent=omarchy\n')
+
+  def test_local_settings_override_vendor_files(self):
+    self.put('vendor/default.conf', '[Theme]\nCurrent=maya\n')
+    self.put(self.dropin, '[Theme]\nCurrent=custom6\n')
+    self.assert_unchanged()
+
+  def test_current_syntax_comments_eof_and_exact_edit(self):
+    for line in ('Current=maya', '  Current = maya\n', 'Current=maya # chosen\n', 'Current=maya\r\n'):
+      with self.subTest(line=line):
+        self.put(self.dropin, '[Theme]\n' + line)
+        self.run_repair()
+        self.assertEqual(self.get(self.dropin), '[Theme]\n' + line.replace('maya', 'omarchy'))
+
+  def test_only_winning_theme_current_is_replaced(self):
+    original = '[Theme]\nCurrent=custom6\n[General]\nCurrent=irrelevant\n[Theme]\nCurrent=maya\n[Users]\nCurrent=omarchy\n'
+    self.put(self.dropin, original)
+    self.run_repair()
+    self.assertEqual(self.get(self.dropin), original.replace('Current=maya', 'Current=omarchy'))
+
+  def test_safe_comments_and_irrelevant_keys_do_not_trigger_edits(self):
+    self.put(self.dropin, '[Theme]\nCurrent=custom6 # chosen\n[General]\nCurrent=maya\n')
+    self.assert_unchanged()
+
+  def test_safe_fallbacks_and_non_qt5_metadata_are_unchanged(self):
+    for theme in ('', 'nosuchtheme'):
+      with self.subTest(theme=theme):
+        self.put(self.dropin, '[Theme]\nCurrent=' + theme + '\n')
+        self.assert_unchanged()
+    self.put(self.dropin, '[Theme]\nCurrent=maya\n')
+    for version in ('6', '7', 'invalid', '"6"', '+6', '06'):
+      with self.subTest(version=version):
+        self.put('themes/maya/metadata.desktop', '[SddmGreeterTheme]\nQtVersion=' + version + '\n')
+        self.assert_unchanged()
+    self.put('themes/maya/metadata.desktop', '[SddmGreeterTheme]\nName=Maya\n')
+    (self.root / 'bin/greeter5').chmod(0o644)
+    self.assert_unchanged()
+    (self.root / 'bin/greeter5').unlink()
+    self.assert_unchanged()
+
+  def test_missing_metadata_in_existing_theme_is_qt5(self):
+    (self.root / 'themes/maya/metadata.desktop').unlink()
+    self.put(self.dropin, '[Theme]\nCurrent=maya\n')
+    self.run_repair()
+    self.assertEqual(self.get(self.dropin), '[Theme]\nCurrent=omarchy\n')
+
+  def test_metadata_key_is_group_scoped_case_sensitive_and_last_wins(self):
+    for metadata in ('[SddmGreeterTheme]\nName=Maya\n[Other]\nQtVersion=6\n',
+                     '[SddmGreeterTheme]\nqtversion=6\n',
+                     '[DEFAULT]\nQtVersion=6\n[SddmGreeterTheme]\nName=Maya\n',
+                     '[SddmGreeterTheme]\nQtVersion=6\nQtVersion=5\n'):
+      with self.subTest(metadata=metadata):
+        self.put('themes/maya/metadata.desktop', metadata)
+        self.put(self.dropin, '[Theme]\nCurrent=maya\n')
+        self.run_repair()
+        self.assertEqual(self.get(self.dropin), '[Theme]\nCurrent=omarchy\n')
+    self.put('themes/custom6/metadata.desktop', '[SddmGreeterTheme]\nQtVersion=6\n[Other]\nQtVersion=5\n')
+    self.put(self.dropin, '[Theme]\nCurrent=custom6\n')
+    self.assert_unchanged()
+
+  def test_effective_theme_dir_and_absolute_theme_names(self):
+    alternate = str(self.root / 'alternate')
+    self.put('alternate/outside6/metadata.desktop', '[SddmGreeterTheme]\nQtVersion=6\n')
+    self.put('alternate/omarchy/metadata.desktop', '[SddmGreeterTheme]\nQtVersion=5\n')
+    self.put('vendor/default.conf', '[Theme]\nThemeDir=' + alternate + '\n')
+    self.put(self.dropin, '[Theme]\nCurrent=outside6\n')
+    self.assert_unchanged()
+    self.put(self.dropin, '[Theme]\nCurrent=' + alternate + '/outside6\n')
+    self.assert_unchanged()
+    self.put(self.dropin, '[Theme]\nCurrent=omarchy\n')
+    self.run_repair()
+    self.assertEqual(self.get(self.dropin), '[Theme]\nCurrent=' + str(self.root / 'themes/omarchy') + '\n')
+    self.assertEqual(self.get('vendor/default.conf'), '[Theme]\nThemeDir=' + alternate + '\n')
+
+  def test_relative_theme_dir_uses_the_system_service_working_directory(self):
+    relative = str(self.root / 'themes').lstrip('/')
+    original = '[Theme]\nThemeDir=' + relative + '\nCurrent=maya\n'
+    self.put(self.dropin, original)
+    self.run_repair()
+    self.assertEqual(self.get(self.dropin), original.replace('Current=maya', 'Current=' + str(self.root / 'themes/omarchy')))
+
+  def test_theme_dir_highest_precedence_is_used(self):
+    self.put('vendor/default.conf', '[Theme]\nThemeDir=/missing\n')
+    self.put(self.dropin, '[Theme]\nCurrent=custom6\n')
+    self.put('etc/sddm.conf', '[Theme]\nThemeDir=' + str(self.root / 'themes') + '\n')
+    self.assert_unchanged()
+
+  def test_backup_is_retained_outside_loaded_dirs_with_original_bytes_and_mode(self):
+    original = '[Theme]\n  Current = maya # selected\n[Users]\nHideUsers=private\n'
+    source = self.put(self.dropin, original)
+    source.chmod(0o640)
+    self.put(self.dropin + '.bak', '# previous administrator backup\n[Users]\nHideUsers=other\n')
+    self.put('backups/10-theme.conf', 'older recovery copy\n')
+    result = self.run_repair()
+    self.assertEqual(self.get(self.dropin + '.bak'), '# previous administrator backup\n[Users]\nHideUsers=other\n')
+    self.assertEqual(self.get('backups/10-theme.conf'), 'older recovery copy\n')
+    copies = [p for p in self.backups() if p.read_text() == original]
+    self.assertEqual(len(copies), 1)
+    self.assertIn(str(copies[0]), result.stdout)
+    self.assertEqual(copies[0].stat().st_mode & 0o777, 0o600)
+    self.assertEqual(source.stat().st_mode & 0o777, 0o640)
+    self.assert_unchanged()
+    self.put(self.dropin, original)
+    self.run_repair()
+    self.assertEqual(len([p for p in self.backups() if p.read_text() == original]), 2)
+
+  def test_backup_failure_leaves_configuration_untouched(self):
+    self.put(self.dropin, '[Theme]\nCurrent=maya\n')
+    self.put('not-a-directory', 'blocked')
+    self.env['OMARCHY_SDDM_BACKUP_DIR'] = str(self.root / 'not-a-directory/backup')
+    self.assert_unchanged(success=False)
+
+  def test_backup_inside_loaded_directory_is_rejected(self):
+    self.put(self.dropin, '[Theme]\nCurrent=maya\n')
+    for directory in ('etc/sddm.conf.d', 'etc/sddm.conf.d/recovery', 'vendor/recovery'):
+      self.env['OMARCHY_SDDM_BACKUP_DIR'] = str(self.root / directory)
+      self.assert_unchanged(success=False)
+
+  def test_symlink_and_writable_config_are_not_replaced(self):
+    source = self.put('outside.conf', '[Theme]\nCurrent=maya\n')
+    link = self.root / self.dropin
+    link.symlink_to(source)
+    self.assert_unchanged(success=False)
+    self.assertTrue(link.is_symlink())
+    link.unlink()
+    self.put(self.dropin, '[Theme]\nCurrent=maya\n').chmod(0o666)
+    self.assert_unchanged(success=False)
+    link.chmod(0o644)
+    os.link(link, self.root / 'hardlink.conf')
+    self.assert_unchanged(success=False)
+
+  def test_unsafe_parent_and_backup_symlink_are_rejected(self):
+    self.put(self.dropin, '[Theme]\nCurrent=maya\n')
+    parent = self.root / 'etc/sddm.conf.d'
+    parent.chmod(0o777)
+    self.assert_unchanged(success=False)
+    parent.chmod(0o755)
+    (self.root / 'backups').rmdir()
+    (self.root / 'backups').symlink_to(self.root / 'home', target_is_directory=True)
+    self.assert_unchanged(success=False)
+
+  def test_ldd_failures_are_pending_and_large_output_is_fully_consumed(self):
+    self.put(self.dropin, '[Theme]\nCurrent=maya\n')
+    self.env['SDDM_TEST_LDD'] = 'good'
+    self.assert_unchanged()
+    self.env['SDDM_TEST_LDD'] = 'error'
+    result = self.run_repair(success=False)
+    self.assertIn('ldd', result.stderr)
+    self.assertEqual(self.get(self.dropin), '[Theme]\nCurrent=maya\n')
+    self.env['SDDM_TEST_LDD'] = 'large'
+    self.run_repair()
+    self.assertEqual(self.get(self.dropin), '[Theme]\nCurrent=omarchy\n')
+
+  def test_changed_configuration_is_not_overwritten(self):
+    self.put(self.dropin, '[Theme]\nCurrent=maya\n')
+    self.env['SDDM_TEST_LDD'] = 'changed'
+    self.run_repair(success=False)
+    self.assertEqual(self.get(self.dropin), '[Theme]\nCurrent=maya\n# administrator edit\n')
+    self.assertEqual(self.backups(), [])
+
+  def test_unsupported_metadata_is_not_guessed(self):
+    self.put(self.dropin, '[Theme]\nCurrent=custom6\n')
+    for value in ('\\\\x36', '"6\n"', '@ByteArray(5)', '@Variant(5)', '@String(5'):
+      with self.subTest(value=value):
+        self.put('themes/custom6/metadata.desktop', '[SddmGreeterTheme]\nQtVersion=' + value + '\n')
+        self.assert_unchanged(success=False)
+
+  def test_malformed_metadata_sections_never_trigger_repair(self):
+    self.put(self.dropin, '[Theme]\nCurrent=custom6\n')
+    for metadata in ('[SddmGreeterTheme\nQtVersion=6\n',
+                     '[SddmGreeterTheme]\nQtVersion=6\n[Other\nQtVersion=5\n',
+                     '[SddmGreeterTheme]]\nQtVersion=6\n'):
+      with self.subTest(metadata=metadata):
+        self.put('themes/custom6/metadata.desktop', metadata)
+        self.assert_unchanged(success=False)
+    self.put(self.dropin, '[Theme]\nCurrent=maya\n')
+    self.put('themes/omarchy/metadata.desktop', '[SddmGreeterTheme\nQtVersion=6\n')
+    self.assert_unchanged(success=False)
+
+  def test_qsettings_string_encoded_qt_versions(self):
+    self.put('themes/omarchy/metadata.desktop', '[SddmGreeterTheme]\nQtVersion=@String(6)\n')
+    for version in ('@String(5)', '"@String(5)"', '@String(+5)', '@String(05)'):
+      with self.subTest(version=version):
+        self.put(self.dropin, '[Theme]\nCurrent=maya\n')
+        self.put('themes/maya/metadata.desktop', '[SddmGreeterTheme]\nQtVersion=' + version + '\n')
+        self.run_repair()
+        self.assertEqual(self.get(self.dropin), '[Theme]\nCurrent=omarchy\n')
+    self.put(self.dropin, '[Theme]\nCurrent=custom6\n')
+    self.put('themes/custom6/metadata.desktop', '[SddmGreeterTheme]\nQtVersion=@String(6)\n')
+    self.assert_unchanged()
+
+  def test_migration_failure_stays_pending_then_completes_only_once(self):
+    self.put(self.dropin, '[Theme]\nCurrent=maya\n')
+    self.put('runtime/migrations/1788380505.sh', Path(migration).read_text())
+    self.put('runtime/migrations/9999999999.sh', 'touch "$HOME/later-ran"\n')
+    self.env['OMARCHY_PATH'] = str(self.root / 'runtime')
+    self.env['OMARCHY_MIGRATION_STATE'] = str(self.root / 'home/markers')
+    runner = str(Path(os.environ['ROOT']) / 'bin/omarchy-migrate')
+    self.env['SDDM_TEST_LDD'] = 'error'
+    result = subprocess.run(['bash', runner], env=self.env, capture_output=True, text=True)
+    self.assertNotEqual(result.returncode, 0, result.stdout + result.stderr)
+    self.assertFalse((self.root / 'home/markers/1788380505.sh').exists())
+    self.assertFalse((self.root / 'home/later-ran').exists())
+    self.env['SDDM_TEST_LDD'] = 'broken'
+    result = subprocess.run(['bash', runner], env=self.env, capture_output=True, text=True)
+    self.assertEqual(result.returncode, 0, result.stdout + result.stderr)
+    self.assertTrue((self.root / 'home/markers/1788380505.sh').exists())
+    self.assertTrue((self.root / 'home/later-ran').exists())
+    self.assertEqual(self.get(self.dropin), '[Theme]\nCurrent=omarchy\n')
+    self.put(self.dropin, '[Theme]\nCurrent=maya\n')
+    before = self.snapshot()
+    result = subprocess.run(['bash', runner], env=self.env, capture_output=True, text=True)
+    self.assertEqual(result.returncode, 0, result.stdout + result.stderr)
+    self.assertEqual(self.snapshot(), before)
+
+  def test_replacement_must_be_available_and_qt6(self):
+    self.put(self.dropin, '[Theme]\nCurrent=maya\n')
+    self.env['SDDM_TEST_QT6_BROKEN'] = '1'
+    self.assert_unchanged(success=False)
+    self.env['SDDM_TEST_QT6_BROKEN'] = '0'
+    self.put('themes/omarchy/metadata.desktop', '[SddmGreeterTheme]\nQtVersion=5\n')
+    self.assert_unchanged(success=False)
+
+
+unittest.main(verbosity=2)
+PY