Init meta.rel_name_active/default only if fields created

parler/managers.py

@@ -50,19 +50,19 @@ def __init__(self, *args, **kwargs):
         self._language = None
 
     def select_related(self, *fields):
-        fields_to_add = []
-        fields_to_exclude = []
+        fields_to_add = set()
+        fields_to_exclude = set([None])  # if rel_name_active, rel_name_default is None
         for extension in self.model._parler_meta:
             if extension.rel_name in fields:
-                fields_to_exclude.append(extension.rel_name)  # Can not select related OneToMany field
-                fields_to_add.append(extension.rel_name_active)
-                fields_to_add.append(extension.rel_name_default)
+                fields_to_exclude.add(extension.rel_name)  # Can not select related OneToMany field
+                fields_to_add.add(extension.rel_name_active)
+                fields_to_add.add(extension.rel_name_default)
             if extension.rel_name_active in fields:
-                fields_to_add.append(extension.rel_name_default)
+                fields_to_add.add(extension.rel_name_default)
             if extension.rel_name_default in fields:
-                fields_to_add.append(extension.rel_name_active)
-        fields = [field for field in fields if field not in fields_to_exclude] + fields_to_add
-        return super(TranslatableQuerySet, self).select_related(*tuple(set(fields)))
+                fields_to_add.add(extension.rel_name_active)
+        fields = set(fields).union(fields_to_add).difference(fields_to_exclude)
+        return super(TranslatableQuerySet, self).select_related(*tuple(fields))
 
     def _clone(self, klass=None, setup=False, **kw):
         if django.VERSION < (1, 9):
@@ -83,8 +83,11 @@ def _add_active_default_select_related(self):
         existing, defer = self.query.deferred_loading
         related_to_add = set()
         for extension in self.model._parler_meta:
-            if extension.rel_name:
+            if not extension.rel_name:
+                continue
+            if extension.rel_name_active:
                 related_to_add.add(extension.rel_name_active)
+            if extension.rel_name_default:
                 related_to_add.add(extension.rel_name_default)
         if defer:
             related_to_add = related_to_add.difference(existing)

parler/models.py

@@ -145,7 +145,10 @@ def create_translations_composite_fk(shared_model, related_name, translated_mode
     """
     if not (1, 8) <= django.VERSION < (2, 0):
         return
+
     meta = shared_model._parler_meta._get_extension_by_related_name(related_name)
+    meta.rel_name_active = related_name + '_active'
+    meta.rel_name_default = related_name + '_default'
     translations_active = CompositeOneToOneVirtualField(
         translated_model,
         null=True,
@@ -569,21 +572,20 @@ def _get_translated_model(self, language_code=None, use_fallback=False, auto_cre
                         pass
                     else:
                         # 2.3 from select related data or fetch from database if not (for django >=1.8, <2.0)
-                        if (1, 8) <= django.VERSION < (2, 0):
-                            if language_code == appsettings.PARLER_LANGUAGES.get_default_language():
-                                try:
-                                    object = getattr(self, meta.rel_name_default) or MISSING
-                                except meta.model.DoesNotExist:
-                                    object = MISSING
-                            elif language_code == self._creation_current_language:
-                                try:
-                                    object = getattr(self, meta.rel_name_active) or MISSING
-                                except meta.model.DoesNotExist:
-                                    object = MISSING
-                                # Double check. It should be almost always object.language_code = language_code
-                                # not hits only if during the queryset iteration active language has changed
-                                if object and object.language_code != language_code:
-                                    object = None
+                        if language_code == appsettings.PARLER_LANGUAGES.get_default_language() and meta.rel_name_default:
+                            try:
+                                object = getattr(self, meta.rel_name_default) or MISSING
+                            except meta.model.DoesNotExist:
+                                object = MISSING
+                        elif language_code == self._creation_current_language and meta.rel_name_active:
+                            try:
+                                object = getattr(self, meta.rel_name_active) or MISSING
+                            except meta.model.DoesNotExist:
+                                object = MISSING
+                            # Double check. It should be almost always object.language_code = language_code
+                            # not hits only if during the queryset iteration active language has changed
+                            if object and object.language_code != language_code:
+                                object = None
                         # 2.4, fetch from database
                         if object is None:
                             try:
@@ -1158,9 +1160,8 @@ def __init__(self, shared_model, translations_model, related_name):
         self.shared_model = shared_model
         self.model = translations_model
         self.rel_name = related_name
-        if related_name:
-            self.rel_name_active = related_name + '_active'
-            self.rel_name_default = related_name + '_default'
+        self.rel_name_active = None
+        self.rel_name_default = None
 
     def get_translated_fields(self):
         """