cfg: clean up None value handling

Remove the need for an internal NoneValue class by making the existence
of the 'default' or 'override' keys signify whether a default or
override is set.

Change-Id: Iacf49553df5ba8414307904a3ee334c7b8c55758

1 files changed, 13 insertions, 23 deletions

diff --git a/openstack/common/cfg.py b/openstack/common/cfg.py
index a56f957..37c65b1 100644
--- a/openstack/common/cfg.py
+++ b/openstack/common/cfg.py
@@ -809,7 +809,7 @@ class OptGroup(object):
         if _is_opt_registered(self._opts, opt):
             return False
 
-        self._opts[opt.dest] = {'opt': opt, 'override': None, 'default': None}
+        self._opts[opt.dest] = {'opt': opt}
 
         return True
 
@@ -1087,7 +1087,7 @@ class ConfigOpts(collections.Mapping):
         if _is_opt_registered(self._opts, opt):
             return False
 
-        self._opts[opt.dest] = {'opt': opt, 'override': None, 'default': None}
+        self._opts[opt.dest] = {'opt': opt}
 
         return True
 
@@ -1175,9 +1175,6 @@ class ConfigOpts(collections.Mapping):
         __import__(module_str)
         self._get_opt_info(name, group)
 
-    class _NoneValue(object):
-        pass
-
     @__clear_cache
     def set_override(self, name, override, group=None):
         """Override an opt value.
@@ -1190,8 +1187,6 @@ class ConfigOpts(collections.Mapping):
         :param group: an option OptGroup object or group name
         :raises: NoSuchOptError, NoSuchGroupError
         """
-        if override is None:
-            override = self._NoneValue()
         opt_info = self._get_opt_info(name, group)
         opt_info['override'] = override
 
@@ -1207,8 +1202,6 @@ class ConfigOpts(collections.Mapping):
         :param group: an option OptGroup object or group name
         :raises: NoSuchOptError, NoSuchGroupError
         """
-        if default is None:
-            default = self._NoneValue()
         opt_info = self._get_opt_info(name, group)
         opt_info['default'] = default
 
@@ -1224,7 +1217,7 @@ class ConfigOpts(collections.Mapping):
         :raises: NoSuchOptError, NoSuchGroupError
         """
         opt_info = self._get_opt_info(name, group)
-        opt_info['override'] = None
+        opt_info.pop('override', None)
 
     @__clear_cache
     def clear_default(self, name, group=None):
@@ -1237,7 +1230,7 @@ class ConfigOpts(collections.Mapping):
         :raises: NoSuchOptError, NoSuchGroupError
         """
         opt_info = self._get_opt_info(name, group)
-        opt_info['default'] = None
+        opt_info.pop('default', None)
 
     def _all_opt_infos(self):
         """A generator function for iteration opt infos."""
@@ -1255,8 +1248,8 @@ class ConfigOpts(collections.Mapping):
     def _unset_defaults_and_overrides(self):
         """Unset any default or override on all options."""
         for info, group in self._all_opt_infos():
-            info['default'] = None
-            info['override'] = None
+            info.pop('default', None)
+            info.pop('override', None)
 
     def disable_interspersed_args(self):
         """Set parsing to stop on the first non-option.
@@ -1379,13 +1372,10 @@ class ConfigOpts(collections.Mapping):
             return self.GroupAttr(self, self._get_group(name))
 
         info = self._get_opt_info(name, group)
-        default, opt, override = [info[k] for k in sorted(info.keys())]
-
-        def _convert_none(value):
-            return None if isinstance(value, self._NoneValue) else value
+        opt = info['opt']
 
-        if override is not None:
-            return _convert_none(override)
+        if 'override' in info:
+            return info['override']
 
         values = []
         if self._cparser is not None:
@@ -1413,8 +1403,8 @@ class ConfigOpts(collections.Mapping):
         if values:
             return values
 
-        if default is not None:
-            return _convert_none(default)
+        if 'default' in info:
+            return info['default']
 
         return opt.default
 
@@ -1506,10 +1496,10 @@ class ConfigOpts(collections.Mapping):
         :raises: RequiredOptError
         """
         for info, group in self._all_opt_infos():
-            default, opt, override = [info[k] for k in sorted(info.keys())]
+            opt = info['opt']
 
             if opt.required:
-                if (default is not None or override is not None):
+                if ('default' in info or 'override' in info):
                     continue
 
                 if self._get(opt.name, group) is None: