fix(qmd): reject unreliable npm listings and restore non-mapping models verbatim

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/lib/qmd.py

@@ -74,12 +74,14 @@ class Setup:
 
     def package_installed(self):
         # npm list exits non-zero on tree problems (ELSPROBLEMS) but still prints valid JSON.
-        output = self.run(['npm', 'list', '--global', '--depth=0', '--json'], check=False) or '{}'
+        output = self.run(['npm', 'list', '--global', '--depth=0', '--json'], check=False)
         try:
             listing = json.loads(output)
         except json.JSONDecodeError:
             raise ValueError('npm list did not return JSON.')
-        return PACKAGE in (listing.get('dependencies') or {})
+        if not isinstance(listing, dict) or not isinstance(listing.get('dependencies'), dict):
+            raise ValueError('npm list did not report the global packages.')
+        return PACKAGE in listing['dependencies']
 
     def require_node(self):
         if not node_version_ok(self.run(['node', '--version'])):
@@ -135,7 +137,7 @@ class Setup:
                 previous = json.loads(output.strip().splitlines()[-1])['previous']
             except (IndexError, KeyError, TypeError, json.JSONDecodeError):
                 raise ValueError('qmd-config set-models returned no previous models.')
-            state['previous_models'] = previous if isinstance(previous, dict) else None
+            state['previous_models'] = previous
             state['models_block'] = True
             atomic_json(self.state_path, state)
         before = {p.name for p in self.models.iterdir()} if self.models.is_dir() else set()

scripts/tests/test-qmd-lib.mjs

@@ -78,6 +78,8 @@ test('runQmdCli runs the CLI entry of QMD_PACKAGE_DIR without a shell', () => {
 
 test('previousModels captures a user models block, null when absent', () => {
   assert.deepEqual(previousModels('models:\n  embed: mine\ncollections: {}\n', YAML), { embed: 'mine' });
+  assert.equal(previousModels('models: custom\n', YAML), 'custom');
+  assert.deepEqual(previousModels('models: [a, b]\n', YAML), ['a', 'b']);
   assert.equal(previousModels('collections: {}\n', YAML), null);
   assert.equal(previousModels('', YAML), null);
 });

scripts/tests/test-qmd-setup.py

@@ -13,9 +13,9 @@ spec.loader.exec_module(qmd)
 
 
 class FakeRunner:
-    def __init__(self, installed=False, gpu='cuda', gpu_result=None, cpu_result=None, previous=None, fail_pull=False):
+    def __init__(self, installed=False, gpu='cuda', gpu_result=None, cpu_result=None, previous=None, fail_pull=False, list_output=None):
         self.calls, self.installed, self.gpu = [], installed, gpu
-        self.previous, self.fail_pull = previous, fail_pull
+        self.previous, self.fail_pull, self.list_output = previous, fail_pull, list_output
         self.results = {'gpu': gpu_result, 'cpu': cpu_result}
 
     def __call__(self, arguments, env=None, timeout=None, check=True):
@@ -27,6 +27,8 @@ class FakeRunner:
             return json.dumps({'previous': self.previous}) + chr(10)
         if self.fail_pull and arguments[:2] == ['qmd', 'pull']:
             raise ValueError('pull failed')
+        if 'npm list' in joined and self.list_output is not None:
+            return self.list_output
         if 'npm list' in joined:
             return json.dumps({'dependencies': {'@tobilu/qmd': {}} if self.installed else {}})
         if 'npm install' in joined:
@@ -198,6 +200,21 @@ class SetupTest(unittest.TestCase):
         self.assertTrue(self.setup(FakeRunner(installed=True)).package_installed())
         self.assertFalse(self.setup(FakeRunner()).package_installed())
 
+    def test_package_installed_rejects_unreliable_listings(self):
+        for output in ('', '  ', 'not json', '{"error": {"code": "ELSPROBLEMS"}}', '{}', '[]'):
+            with self.assertRaises(ValueError, msg=repr(output)):
+                self.setup(FakeRunner(list_output=output)).package_installed()
+        self.assertTrue(self.setup(FakeRunner(list_output='{"dependencies": {"@tobilu/qmd": {}}, "error": {}}')).package_installed())
+        self.assertFalse(self.setup(FakeRunner(list_output='{"dependencies": {}}')).package_installed())
+
+    def test_non_mapping_previous_models_are_restored_verbatim(self):
+        runner = FakeRunner(previous='custom.gguf')
+        setup = self.setup(runner)
+        setup.enable(['claude'])
+        self.assertEqual(self.state()['previous_models'], 'custom.gguf')
+        setup.disable(['claude'])
+        self.assertTrue(any(c[-2:] == ['restore-models', '"custom.gguf"'] for c in runner.calls))
+
     def test_dry_run_changes_nothing(self):
         runner = FakeRunner()
         self.setup(runner, dry_run=True).enable(['claude'])