Throw TypeError in repository enable/disable macros

Currently we do not validate the type of the reponames argument to the
enable_extra_repos and disable_extra_repos macros. It should be a list,
but we merged a call where the argument was a string, which interpreted
as a list of single characters ('e', 'p', 'e', 'l'), and silently
ignored.

This change validates that the reponames argument is a list to avoid
this issue.

Change-Id: I497c8b2c1dc548e678698474d3604664cf8eeb07

kolla/template/methods.py

@@ -88,6 +88,9 @@ def handle_repos(context, reponames, mode):
     else:
         raise KeyError
 
+    if not isinstance(reponames, list):
+        raise TypeError("First argument should be a list of repositories")
+
     repofile = os.path.dirname(os.path.realpath(__file__)) + '/repos.yaml'
     with open(repofile, 'r') as repos_file:
         repo_data = {}

kolla/tests/test_methods.py

@@ -150,3 +150,16 @@ class MethodsTest(base.TestCase):
         result = methods.handle_repos(template_vars, ['grafana'], 'disable')
         expectCmd = ''
         self.assertEqual(expectCmd, result)
+
+    def test_handle_repos_string(self):
+        template_vars = {
+            'base_arch': 'x86_64',
+            'base_distro': 'debian',
+            'base_package_type': 'deb'
+        }
+
+        self.assertRaisesRegex(TypeError,
+                               r'First argument should be a list of '
+                               r'repositories',
+                               methods.handle_repos, template_vars, 'grafana',
+                               'disable')