Fix default language assignment once and for all.

Stop trying to be clever and magical and just make the caller pass in a
damn primary key.

pokedex/db/multilang.py

@@ -157,46 +157,36 @@ def create_translation_table(_table_name, foreign_class, relation_name,
 class MultilangSession(Session):
     """A tiny Session subclass that adds support for a default language.
 
-    Caller will need to assign something to `default_language` before this will
-    actually work.
+    Needs to be used with `MultilangScopedSession`, below.
     """
-    _default_language_id = 0  # Better fill this in, caller
+    default_language_id = None
 
     def __init__(self, *args, **kwargs):
-        self.language_class = kwargs.pop('language_class')
+        if 'default_language_id' in kwargs:
+            self.default_language_id = kwargs.pop('default_language_id')
+
         super(MultilangSession, self).__init__(*args, **kwargs)
 
-    @property
-    def default_language(self):
-        return self.query(self.language_class) \
-            .filter_by(id=self._default_language_id) \
-            .one()
-
-    @default_language.setter
-    def default_language(self, new):
-        self._default_language_id = new.id
-
-    @default_language.deleter
-    def default_language(self):
-        try:
-            del self._default_language_id
-        except AttributeError:
-            pass
-
     def execute(self, clause, params=None, *args, **kwargs):
         if not params:
             params = {}
-        params.setdefault('_default_language_id', self._default_language_id)
+        params.setdefault('_default_language_id', self.default_language_id)
+
         return super(MultilangSession, self).execute(
             clause, params, *args, **kwargs)
 
 class MultilangScopedSession(ScopedSession):
     """Dispatches language selection to the attached Session."""
 
-    @property
-    def default_language(self):
-        return self.registry().default_language
+    def __init__(self, *args, **kwargs):
+        super(MultilangScopedSession, self).__init__(*args, **kwargs)
 
-    @default_language.setter
-    def default_language(self, new):
-        self.registry().default_language = new
+    @property
+    def default_language_id(self):
+        """Passes the new default language id through to the current session.
+        """
+        return self.registry().default_language_id
+
+    @default_language_id.setter
+    def default_language_id(self, new):
+        self.registry().default_language_id = new