attributes in Option are now read-only if option set in Config (_name is everytime read-only)

tiramisu/option.py

@@ -91,7 +91,37 @@ class BaseInformation(object):
                                        self.__class__.__name__))
 
 
-class Option(BaseInformation):
+class _ReadOnlyOption(BaseInformation):
+    __slots__ = ('_readonly',)
+
+    def __setattr__(self, name, value):
+        is_readonly = False
+        # never change _name
+        if name == '_name':
+            try:
+                self._name
+                #so _name is already set
+                is_readonly = True
+            except:
+                pass
+        try:
+            if self._readonly is True:
+                if value is True:
+                    # already readonly and try to re set readonly
+                    # don't raise, just exit
+                    return
+                is_readonly = True
+        except AttributeError:
+            pass
+        if is_readonly:
+            raise AttributeError(_("'{0}' ({1}) object attribute '{2}' is"
+                                   " read-only").format(
+                                       self.__class__.__name__, self._name,
+                                       name))
+        object.__setattr__(self, name, value)
+
+
+class Option(_ReadOnlyOption):
     """
     Abstract base class for configuration option's.
 
@@ -450,10 +480,9 @@ else:
                 raise ValueError(_('value must be an unicode'))
 
 
-class SymLinkOption(object):
+class SymLinkOption(_ReadOnlyOption):
     __slots__ = ('_name', '_opt')
     _opt_type = 'symlink'
-    _consistencies = None
 
     def __init__(self, name, opt):
         self._name = name
@@ -462,9 +491,10 @@ class SymLinkOption(object):
                                'must be an option '
                                'for symlink {0}').format(name))
         self._opt = opt
+        self._readonly = True
 
     def __getattr__(self, name):
-        if name in ('_name', '_opt', '_consistencies'):
+        if name in ('_name', '_opt', '_opt_type', '_readonly'):
             return object.__getattr__(self, name)
         else:
             return getattr(self._opt, name)
@@ -684,13 +714,13 @@ class DomainnameOption(Option):
             raise ValueError(_('invalid domainname'))
 
 
-class OptionDescription(BaseInformation):
+class OptionDescription(_ReadOnlyOption):
     """Config's schema (organisation, group) and container of Options
     The `OptionsDescription` objects lives in the `tiramisu.config.Config`.
     """
     __slots__ = ('_name', '_requires', '_cache_paths', '_group_type',
                  '_properties', '_children', '_consistencies',
-                 '_calc_properties', '__weakref__')
+                 '_calc_properties', '__weakref__', '_readonly', '_impl_informations')
 
     def __init__(self, name, doc, children, requires=None, properties=None):
         """
@@ -731,6 +761,8 @@ class OptionDescription(BaseInformation):
         return self.impl_get_information('doc')
 
     def __getattr__(self, name):
+        if name in self.__slots__:
+            return object.__getattribute__(self, name)
         try:
             return self._children[1][self._children[0].index(name)]
         except ValueError:
@@ -769,6 +801,7 @@ class OptionDescription(BaseInformation):
                          _currpath=None,
                          _consistencies=None):
         if _currpath is None and self._cache_paths is not None:
+            # cache already set
             return
         if _currpath is None:
             save = True
@@ -787,6 +820,7 @@ class OptionDescription(BaseInformation):
                 raise ConflictError(_('duplicate option: {0}').format(option))
 
             cache_option.append(option)
+            option._readonly = True
             cache_path.append(str('.'.join(_currpath + [attr])))
             if not isinstance(option, OptionDescription):
                 if option._consistencies is not None:
@@ -807,6 +841,7 @@ class OptionDescription(BaseInformation):
         if save:
             self._cache_paths = (tuple(cache_option), tuple(cache_path))
             self._consistencies = _consistencies
+            self._readonly = True
 
     def impl_get_opt_by_path(self, path):
         try: