Alter save mechanism on Django 1.4

awx/main/models/base.py

@@ -9,6 +9,7 @@ import shlex
 import yaml
 
 # Django
+import django
 from django.conf import settings
 from django.db import models
 from django.core.exceptions import ValidationError
@@ -146,15 +147,66 @@ class BaseModel(models.Model):
         return update_fields
 
     def save(self, *args, **kwargs):
-        # For compatibility with Django 1.4.x, attempt to handle any calls to
-        # save that pass update_fields.
-        try:
-            super(BaseModel, self).save(*args, **kwargs)
-        except TypeError:
-            if 'update_fields' not in kwargs:
-                raise
+        """Save the model instance to the database.
+
+        Additionally, if `update_fields` is present but we are on a version
+        of Django that doesn't yet support it, handle support for it
+        ourselves.
+        """
+        # If we're trying to use update_fields and Django doesn't yet support
+        # it, then we need to do the save using the manager's update method,
+        # which is the only way to save only individual fields on earlier
+        # versions of Django.
+        update_fields = kwargs.get('update_fields', None)
+        if update_fields is not None and django.VERSION < (1, 5):
+            # Sanity check: If update_fields is empty, do nothing.
+            if len(update_fields) == 0:
+                return
+
+            # We need to manually send the pre_save signal; Django won't do it
+            # using a manager update.
+            #
+            # This code is copied from Django itself.
+            # See: django/db/models/base.py
+            #
+            # Django's copyright and license are found here:
+            # https://github.com/django/django/blob/master/LICENSE
+            cls = origin = self.__class__
+            if cls._meta.proxy:
+                cls = cls._meta.concrete_model
+            meta = cls._meta
+            if not meta.auto_created:
+                # It's safe to send `update_fields` here since signal listeners
+                # are required to take **kwargs.
+                signals.pre_save.send(sender=origin, instance=self,
+                                      raw=kwargs.get('raw', False),
+                                      using=kwargs.get('using', None),
+                                      update_fields=update_fields)
+            # (end copied code)
+
+            # Actually update the record. We do this with an update off of
+            # the manager. Also, since update_fields in 1.5+ requires the
+            # record already exist, I do not need to check for that here.
+            to_update = {}
+            for field in update_fields:
+                to_update[field] = getattr(self, field)
+            cls.objects.filter(pk=self.pk).update(**to_update)
+
+            # Send the post-save signal.
+            if not meta.auto_created:
+                signals.post_save.send(sender=origin, instance=self,
+                                       raw=kwargs.get('raw', False),
+                                       using=kwargs.get('using', None),
+                                       update_fields=update_fields)
+
+            # Now we're done; return None.
+            return
+
+        # This is either Django 1.5+, or not using update_fields.
+        # Either way, we're in good shape.
+        if 'update_fields' in kwargs and kwargs['update_fields'] is None:
             kwargs.pop('update_fields')
-            super(BaseModel, self).save(*args, **kwargs)
+        return super(BaseModel, self).save(*args, **kwargs)
 
 
 class CreatedModifiedModel(BaseModel):