Fix some map_replace issues

While testing I discovered a couple of corner cases not previously
handled:
- If you provide values/keys via a get_attr reference it's possible for
them to be None during validation
- If the input map has an unhashable value, it breaks the values replacement
so we need to tolerate a failure to lookup an unhashable key in the values
data.

Change-Id: I14d92056e0a07816a216aba752711887e8ac0aa5

doc/source/template_guide/hot_spec.rst

@@ -1329,6 +1329,10 @@ The keys/values mappings are optional, either or both may be specified.
 Note that an error is raised if a replacement defined in "keys" results
 in a collision with an existing keys in the input or output map.
 
+Also note that while unhashable values (e.g lists) in the input map are valid,
+they will be ignored by the values replacement, because no key can be defined
+in the values mapping to define their replacement.
+
 yaql
 ----
 The ``yaql`` evaluates yaql expression on a given data.

heat/engine/hot/functions.py

@@ -542,8 +542,8 @@ class MapReplace(function.Function):
                 raise ValueError(_('Incorrect arguments to "%(fn_name)s" '
                                    'should be: %(example)s') % self.fmt_data)
 
-        repl_keys = repl_map.get('keys', {})
-        repl_values = repl_map.get('values', {})
+        repl_keys = ensure_map(repl_map.get('keys', {}))
+        repl_values = ensure_map(repl_map.get('values', {}))
         ret_map = {}
         for k, v in six.iteritems(in_map):
             key = repl_keys.get(k)
@@ -559,7 +559,11 @@ class MapReplace(function.Function):
                 msg = _('key replacement %s collides with '
                         'a key in the output map')
                 raise ValueError(msg % key)
-            value = repl_values.get(v, v)
+            try:
+                value = repl_values.get(v, v)
+            except TypeError:
+                # If the value is unhashable, we get here
+                value = v
             ret_map[key] = value
         return ret_map
 

heat/tests/test_hot.py

@@ -926,6 +926,30 @@ class HOTemplateTest(common.HeatTestCase):
         self.assertEqual({'f1': 'b1', 'F2': 'b2'},
                          resolved)
 
+    def test_map_replace_none_values(self):
+        snippet = {'map_replace': [{'f1': 'b1', 'f2': 'b2'},
+                                   {'values': None}]}
+        tmpl = template.Template(hot_newton_tpl_empty)
+        resolved = self.resolve(snippet, tmpl)
+        self.assertEqual({'f1': 'b1', 'f2': 'b2'},
+                         resolved)
+
+    def test_map_replace_none_keys(self):
+        snippet = {'map_replace': [{'f1': 'b1', 'f2': 'b2'},
+                                   {'keys': None}]}
+        tmpl = template.Template(hot_newton_tpl_empty)
+        resolved = self.resolve(snippet, tmpl)
+        self.assertEqual({'f1': 'b1', 'f2': 'b2'},
+                         resolved)
+
+    def test_map_replace_unhashable_value(self):
+        snippet = {'map_replace': [{'f1': 'b1', 'f2': []},
+                                   {'values': {}}]}
+        tmpl = template.Template(hot_newton_tpl_empty)
+        resolved = self.resolve(snippet, tmpl)
+        self.assertEqual({'f1': 'b1', 'f2': []},
+                         resolved)
+
     def test_map_replace_keys_collide(self):
         snippet = {'map_replace': [{'f1': 'b1', 'f2': 'b2'},
                                    {'keys': {'f2': 'f1'}}]}