Validate layers for options (fixes #173)

Ensure that options are only set for layers that are included.
This also ensures that one doesn't forget to nest the options under the
layer name.

Note: The `additionalProperties` is actually sufficient, but produces a
somewhat obscure error message.

charmtools/build/tactics.py

@@ -374,7 +374,8 @@ def __init__(self, *args, **kwargs):
         super(LayerYAML, self).__init__(*args, **kwargs)
         self.schema = {
             'type': 'object',
-            'properties': {}
+            'properties': {},
+            'additionalProperties': False,
         }
 
     @property
@@ -405,6 +406,14 @@ def combine(self, existing):
 
     def lint(self):
         self.read()
+        defined_layer_names = set(self.schema['properties'].keys())
+        options_layer_names = set(self.data['options'].keys())
+        unknown_layer_names = options_layer_names - defined_layer_names
+        if unknown_layer_names:
+            log.error('Options set for undefined layer{s}: {layers}'.format(
+                s='s' if len(unknown_layer_names) > 1 else '',
+                layers=', '.join(unknown_layer_names)))
+            return False
         validator = extend_with_default(jsonschema.Draft4Validator)(self.schema)
         valid = True
         for error in validator.iter_errors(self.data['options']):

tests/test_build.py

@@ -68,7 +68,7 @@ def test_tester_layer(self):
         cyaml_data = yaml.load(cyaml.open())
         self.assertEquals(cyaml_data['includes'], ['trusty/mysql'])
         self.assertEquals(cyaml_data['is'], 'foo')
-        self.assertEquals(cyaml_data['options']['mysql']['qux'], 'one')
+        self.assertEquals(cyaml_data['options']['trusty/mysql']['qux'], 'one')
 
         self.assertTrue((base / "hooks/config-changed").exists())
 
@@ -328,9 +328,6 @@ def test_layer_options(self, log):
         top = build.tactics.LayerYAML(entity, top_layer, target, config)
         top.data = {
             'options': {
-                'base': {
-                    'bar': 'bah',
-                },
             },
             'defines': {
                 'qux': {
@@ -341,6 +338,12 @@ def test_layer_options(self, log):
             }
         }
         assert top.lint()
+        top.data['options'].update({
+            'base': {
+                'bar': 'bah',
+            }
+        })
+        assert not top.lint()
         top.combine(base)
         assert not top.lint()
         log.error.assert_called_with('Invalid value for option %s: %s',

tests/trusty/tester/layer.yaml

@@ -7,5 +7,5 @@ config:
 tactics:
     - layer.custom.READMETactic
 options:
-  mysql:
+  trusty/mysql:
     qux: 'one'