Implement support for translated fields in save's update_fields argum…

…ent.

docs/public/models.rst

@@ -117,13 +117,19 @@ get_available_languages
 save
 ====
 
-.. method:: save(force_insert=False, force_update=False, using=None)
+.. method:: save(force_insert=False, force_update=False, using=None, update_fields=None)
 
     Overrides :meth:`~django.db.models.Model.save`.
 
     This method runs an extra query to save the translation cached on
     this instance, if any translation was cached.
 
+    It accepts both translated and untranslated fields in ``update_fields``.
+
+    - If only untranslated fields are specified, the extra query will be skipped.
+    - If only translated fields are specified, the shared model update will be skipped.
+      Note that this means signals will not be triggered.
+
 
 **********************
 Working with relations

docs/public/release_notes.rst

@@ -13,6 +13,14 @@ New features:
 - It is now possible to specify a :ref:`custom translation base <custom-translation-models>`
   model, allowing advanced translation manipulation, such as controlling their loading
   with :meth:`~django.db.models.Model.from_db`.
+- Translated model's :meth:`~django.db.models.Model.save` method now accepts translated field
+  names in ``update_fields``. Also, if only translated fields, or only untranslated fields
+  are specified in ``update_fields``, the extra query will be skipped.
+
+Compatibility Warnings:
+
+- Saving of translations now happens in the model's :meth:`~django.db.models.Model.save` method.
+  It used to happen in the ``post_save`` signal.
 
 .. release 1.4.0
 

hvad/models.py

@@ -252,13 +252,29 @@ def __init__(self, *args, **kwargs):
             tkwargs['language_code'] = tkwargs.get('language_code') or get_language()
             set_cached_translation(self, self._meta.translations_model(**tkwargs))
 
-    @classmethod
-    def save_translations(cls, instance, **kwargs):
-        'Signal handler for post_save'
-        translation = get_cached_translation(instance)
-        if translation is not None:
-            translation.master = instance
-            translation.save()
+    def save(self, *args, **skwargs):
+        translation_model = self._meta.translations_model
+        translation = get_cached_translation(self)
+        tkwargs = skwargs.copy()
+
+        # split update_fields in shared/translated fields
+        update_fields = skwargs.get('update_fields')
+        if update_fields is not None:
+            supdate, tupdate = [], []
+            for name in update_fields:
+                if name in self._translated_field_names and not name in ('id', 'master_id', 'master'):
+                    tupdate.append(name)
+                else:
+                    supdate.append(name)
+            skwargs['update_fields'], tkwargs['update_fields'] = supdate, tupdate
+
+        # save share and translated model in a single transaction
+        if update_fields is None or skwargs['update_fields']:
+            super(TranslatableModel, self).save(*args, **skwargs)
+        if (update_fields is None or tkwargs['update_fields']) and translation is not None:
+            translation.master = self
+            translation.save(*args, **tkwargs)
+    save.alters_data = True
 
     def translate(self, language_code):
         ''' Create a new translation for current instance.
@@ -269,6 +285,7 @@ def translate(self, language_code):
             self._meta.translations_model(language_code=language_code)
         )
         return self
+    translate.alters_data = True
 
     def safe_translation_getter(self, name, default=None):
         cache = get_cached_translation(self)
@@ -469,7 +486,4 @@ def prepare_translatable_model(sender, **kwargs):
             model._meta
         )
 
-    # Attach save_translations
-    post_save.connect(model.save_translations, sender=model, weak=False)
-
 class_prepared.connect(prepare_translatable_model)

hvad/tests/basic.py

@@ -397,6 +397,50 @@ def test_create_lang_deprecation(self):
             )
 
 
+class UpdateTest(HvadTestCase, NormalFixture):
+    normal_count = 2
+
+    def test_basic_update(self):
+        obj = Normal.objects.language('en').get(pk=self.normal_id[1])
+        obj.shared_field = 'update_shared'
+        obj.translated_field = 'update_translated'
+        with self.assertNumQueries(2):
+            obj.save()
+        obj = Normal.objects.language().get(pk=self.normal_id[1])
+        self.assertEqual(obj.shared_field, 'update_shared')
+        self.assertEqual(obj.translated_field, 'update_translated')
+
+    def test_force_update(self):
+        obj = Normal.objects.language('en').get(pk=self.normal_id[1])
+        obj.shared_field = 'update_shared'
+        obj.translated_field = 'update_translated'
+        with self.assertNumQueries(2):
+            obj.save(force_update=True)
+        obj = Normal.objects.language().get(pk=self.normal_id[1])
+        self.assertEqual(obj.shared_field, 'update_shared')
+        self.assertEqual(obj.translated_field, 'update_translated')
+
+    def test_update_fields_shared(self):
+        obj = Normal.objects.language('en').get(pk=self.normal_id[1])
+        obj.shared_field = 'update_shared'
+        obj.translated_field = 'update_translated'
+        with self.assertNumQueries(1):
+            obj.save(update_fields=['shared_field'])
+        obj = Normal.objects.language().get(pk=self.normal_id[1])
+        self.assertEqual(obj.shared_field, 'update_shared')
+        self.assertEqual(obj.translated_field, NORMAL[1].translated_field['en'])
+
+    def test_update_fields_translated(self):
+        obj = Normal.objects.language('en').get(pk=self.normal_id[1])
+        obj.shared_field = 'update_shared'
+        obj.translated_field = 'update_translated'
+        with self.assertNumQueries(1):
+            obj.save(update_fields=['translated_field'])
+        obj = Normal.objects.language().get(pk=self.normal_id[1])
+        self.assertEqual(obj.shared_field, NORMAL[1].shared_field)
+        self.assertEqual(obj.translated_field, 'update_translated')
+
+
 class DeleteTest(HvadTestCase, NormalFixture):
     normal_count = 2