Fixed #13552 -- Added a 'using' parameter to database signals. Thanks to gmandx for the suggestion, and Andrew Godwin for the patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@13538 bcc190cf-cafb-0310-a4f2-bffc1f526a37

AUTHORS

@@ -190,6 +190,7 @@ answer newbie questions, and generally made Django that much better:
     martin.glueck@gmail.com
     Artyom Gnilov <boobsd@gmail.com>
     Ben Godfrey <http://aftnn.org>
+    Andrew Godwin <andrew@aeracode.org>
     GomoX <gomo@datafull.com>
     Guilherme Mesquita Gondim <semente@taurinus.org>
     Mario Gonzalez <gonzalemario@gmail.com>

django/db/models/base.py

@@ -456,7 +456,7 @@ class Model(object):
             meta = cls._meta
 
         if origin and not meta.auto_created:
-            signals.pre_save.send(sender=origin, instance=self, raw=raw)
+            signals.pre_save.send(sender=origin, instance=self, raw=raw, using=using)
 
         # If we are in a raw save, save the object exactly as presented.
         # That means that we don't try to be smart about saving attributes
@@ -540,7 +540,7 @@ class Model(object):
         # Signal that the save is complete
         if origin and not meta.auto_created:
             signals.post_save.send(sender=origin, instance=self,
-                created=(not record_exists), raw=raw)
+                created=(not record_exists), raw=raw, using=using)
 
     save_base.alters_data = True
 

django/db/models/fields/related.py

@@ -566,7 +566,7 @@ def create_many_related_manager(superclass, rel=False):
                     # duplicate data row for symmetrical reverse entries.
                     signals.m2m_changed.send(sender=rel.through, action='pre_add',
                         instance=self.instance, reverse=self.reverse,
-                        model=self.model, pk_set=new_ids)
+                        model=self.model, pk_set=new_ids, using=db)
                 # Add the ones that aren't there already
                 for obj_id in new_ids:
                     self.through._default_manager.using(db).create(**{
@@ -578,7 +578,7 @@ def create_many_related_manager(superclass, rel=False):
                     # duplicate data row for symmetrical reverse entries.
                     signals.m2m_changed.send(sender=rel.through, action='post_add',
                         instance=self.instance, reverse=self.reverse,
-                        model=self.model, pk_set=new_ids)
+                        model=self.model, pk_set=new_ids, using=db)
 
         def _remove_items(self, source_field_name, target_field_name, *objs):
             # source_col_name: the PK colname in join_table for the source object
@@ -594,14 +594,16 @@ def create_many_related_manager(superclass, rel=False):
                         old_ids.add(obj.pk)
                     else:
                         old_ids.add(obj)
+                # Work out what DB we're operating on
+                db = router.db_for_write(self.through.__class__, instance=self.instance)
+                # Send a signal to the other end if need be.
                 if self.reverse or source_field_name == self.source_field_name:
                     # Don't send the signal when we are deleting the
                     # duplicate data row for symmetrical reverse entries.
                     signals.m2m_changed.send(sender=rel.through, action="pre_remove",
                         instance=self.instance, reverse=self.reverse,
-                        model=self.model, pk_set=old_ids)
+                        model=self.model, pk_set=old_ids, using=db)
                 # Remove the specified objects from the join table
-                db = router.db_for_write(self.through.__class__, instance=self.instance)
                 self.through._default_manager.using(db).filter(**{
                     source_field_name: self._pk_val,
                     '%s__in' % target_field_name: old_ids
@@ -611,17 +613,17 @@ def create_many_related_manager(superclass, rel=False):
                     # duplicate data row for symmetrical reverse entries.
                     signals.m2m_changed.send(sender=rel.through, action="post_remove",
                         instance=self.instance, reverse=self.reverse,
-                        model=self.model, pk_set=old_ids)
+                        model=self.model, pk_set=old_ids, using=db)
 
         def _clear_items(self, source_field_name):
+            db = router.db_for_write(self.through.__class__, instance=self.instance)
             # source_col_name: the PK colname in join_table for the source object
             if self.reverse or source_field_name == self.source_field_name:
                 # Don't send the signal when we are clearing the
                 # duplicate data rows for symmetrical reverse entries.
                 signals.m2m_changed.send(sender=rel.through, action="pre_clear",
                     instance=self.instance, reverse=self.reverse,
-                    model=self.model, pk_set=None)
+                    model=self.model, pk_set=None, using=db)
-            db = router.db_for_write(self.through.__class__, instance=self.instance)
             self.through._default_manager.using(db).filter(**{
                 source_field_name: self._pk_val
             }).delete()
@@ -630,7 +632,7 @@ def create_many_related_manager(superclass, rel=False):
                 # duplicate data rows for symmetrical reverse entries.
                 signals.m2m_changed.send(sender=rel.through, action="post_clear",
                     instance=self.instance, reverse=self.reverse,
-                    model=self.model, pk_set=None)
+                    model=self.model, pk_set=None, using=db)
 
     return ManyRelatedManager
 

django/db/models/query.py

@@ -1311,7 +1311,8 @@ def delete_objects(seen_objs, using):
             # Pre-notify all instances to be deleted.
             for pk_val, instance in items:
                 if not cls._meta.auto_created:
-                    signals.pre_delete.send(sender=cls, instance=instance)
+                    signals.pre_delete.send(sender=cls, instance=instance,
+                        using=using)
 
             pk_list = [pk for pk,instance in items]
 
@@ -1343,7 +1344,7 @@ def delete_objects(seen_objs, using):
                         setattr(instance, field.attname, None)
 
                 if not cls._meta.auto_created:
-                    signals.post_delete.send(sender=cls, instance=instance)
+                    signals.post_delete.send(sender=cls, instance=instance, using=using)
                 setattr(instance, cls._meta.pk.attname, None)
 
         if forced_managed:

django/db/models/signals.py

@@ -5,12 +5,12 @@ class_prepared = Signal(providing_args=["class"])
 pre_init = Signal(providing_args=["instance", "args", "kwargs"])
 post_init = Signal(providing_args=["instance"])
 
-pre_save = Signal(providing_args=["instance", "raw"])
+pre_save = Signal(providing_args=["instance", "raw", "using"])
-post_save = Signal(providing_args=["instance", "raw", "created"])
+post_save = Signal(providing_args=["instance", "raw", "created", "using"])
 
-pre_delete = Signal(providing_args=["instance"])
+pre_delete = Signal(providing_args=["instance", "using"])
-post_delete = Signal(providing_args=["instance"])
+post_delete = Signal(providing_args=["instance", "using"])
 
 post_syncdb = Signal(providing_args=["class", "app", "created_models", "verbosity", "interactive"])
 
-m2m_changed = Signal(providing_args=["action", "instance", "reverse", "model", "pk_set"])
+m2m_changed = Signal(providing_args=["action", "instance", "reverse", "model", "pk_set", "using"])

docs/ref/signals.txt

@@ -33,9 +33,9 @@ module system.
     If you override these methods on your model, you must call the parent class'
     methods for this signals to be sent.
 
-	Note also that Django stores signal handlers as weak references by default,
+    Note also that Django stores signal handlers as weak references by default,
-	so if your handler is a local function, it may be garbage collected.  To
+    so if your handler is a local function, it may be garbage collected.  To
-	prevent this, pass ``weak=False`` when you call the signal's :meth:`~django.dispatch.Signal.connect`.
+    prevent this, pass ``weak=False`` when you call the signal's :meth:`~django.dispatch.Signal.connect`.
 
 pre_init
 --------
@@ -113,6 +113,9 @@ Arguments sent with this signal:
     ``instance``
         The actual instance being saved.
 
+    ``using``
+        The database alias being used.
+
 post_save
 ---------
 
@@ -133,6 +136,9 @@ Arguments sent with this signal:
     ``created``
         A boolean; ``True`` if a new record was created.
 
+    ``using``
+        The database alias being used.
+
 pre_delete
 ----------
 
@@ -150,6 +156,9 @@ Arguments sent with this signal:
     ``instance``
         The actual instance being deleted.
 
+    ``using``
+        The database alias being used.
+
 post_delete
 -----------
 
@@ -170,6 +179,9 @@ Arguments sent with this signal:
         Note that the object will no longer be in the database, so be very
         careful what you do with this instance.
 
+    ``using``
+        The database alias being used.
+
 m2m_changed
 -----------
 
@@ -215,8 +227,8 @@ Arguments sent with this signal:
             Sent *after* the relation is cleared
 
     ``reverse``
-    	Indicates which side of the relation is updated (i.e., if it is the
+        Indicates which side of the relation is updated (i.e., if it is the
-    	forward or reverse relation that is being modified).
+        forward or reverse relation that is being modified).
 
     ``model``
         The class of the objects that are added to, removed from or cleared
@@ -228,6 +240,9 @@ Arguments sent with this signal:
 
         For the ``"clear"`` action, this is ``None``.
 
+    ``using``
+        The database alias being used.
+
 For example, if a ``Pizza`` can have multiple ``Topping`` objects, modeled
 like this:
 
@@ -266,6 +281,8 @@ the arguments sent to a :data:`m2m_changed` handler would be:
                     ``Pizza``)
 
     ``pk_set``      ``[t.id]`` (since only ``Topping t`` was added to the relation)
+
+    ``using``       ``"default"`` (since the default router sends writes here)
     ==============  ============================================================
 
 And if we would then do something like this:
@@ -293,6 +310,8 @@ the arguments sent to a :data:`m2m_changed` handler would be:
 
     ``pk_set``      ``[p.id]`` (since only ``Pizza p`` was removed from the
                     relation)
+
+    ``using``       ``"default"`` (since the default router sends writes here)
     ==============  ============================================================
 
 class_prepared

tests/regressiontests/multiple_database/tests.py

@@ -7,6 +7,7 @@ from django.conf import settings
 from django.contrib.auth.models import User
 from django.core import management
 from django.db import connections, router, DEFAULT_DB_ALIAS
+from django.db.models import signals
 from django.db.utils import ConnectionRouter
 from django.test import TestCase
 
@@ -1619,3 +1620,114 @@ class PickleQuerySetTestCase(TestCase):
             Book.objects.using(db).create(title='Dive into Python', published=datetime.date(2009, 5, 4))
             qs = Book.objects.all()
             self.assertEqual(qs.db, pickle.loads(pickle.dumps(qs)).db)
+
+
+class DatabaseReceiver(object):
+    """
+    Used in the tests for the database argument in signals (#13552)
+    """
+    def __call__(self, signal, sender, **kwargs):
+        self._database = kwargs['using']
+
+class WriteToOtherRouter(object):
+    """
+    A router that sends all writes to the other database.
+    """
+    def db_for_write(self, model, **hints):
+        return "other"
+
+class SignalTests(TestCase):
+    multi_db = True
+
+    def setUp(self):
+        self.old_routers = router.routers
+
+    def tearDown(self):
+        router.routser = self.old_routers
+
+    def _write_to_other(self):
+        "Sends all writes to 'other'."
+        router.routers = [WriteToOtherRouter()]
+
+    def _write_to_default(self):
+        "Sends all writes to the default DB"
+        router.routers = self.old_routers
+
+    def test_database_arg_save_and_delete(self):
+        """
+        Tests that the pre/post_save signal contains the correct database.
+        (#13552)
+        """
+        # Make some signal receivers
+        pre_save_receiver = DatabaseReceiver()
+        post_save_receiver = DatabaseReceiver()
+        pre_delete_receiver = DatabaseReceiver()
+        post_delete_receiver = DatabaseReceiver()
+        # Make model and connect receivers
+        signals.pre_save.connect(sender=Person, receiver=pre_save_receiver)
+        signals.post_save.connect(sender=Person, receiver=post_save_receiver)
+        signals.pre_delete.connect(sender=Person, receiver=pre_delete_receiver)
+        signals.post_delete.connect(sender=Person, receiver=post_delete_receiver)
+        p = Person.objects.create(name='Darth Vader')
+        # Save and test receivers got calls
+        p.save()
+        self.assertEqual(pre_save_receiver._database, DEFAULT_DB_ALIAS)
+        self.assertEqual(post_save_receiver._database, DEFAULT_DB_ALIAS)
+        # Delete, and test
+        p.delete()
+        self.assertEqual(pre_delete_receiver._database, DEFAULT_DB_ALIAS)
+        self.assertEqual(post_delete_receiver._database, DEFAULT_DB_ALIAS)
+        # Save again to a different database
+        p.save(using="other")
+        self.assertEqual(pre_save_receiver._database, "other")
+        self.assertEqual(post_save_receiver._database, "other")
+        # Delete, and test
+        p.delete(using="other")
+        self.assertEqual(pre_delete_receiver._database, "other")
+        self.assertEqual(post_delete_receiver._database, "other")
+
+    def test_database_arg_m2m(self):
+        """
+        Test that the m2m_changed signal has a correct database arg (#13552)
+        """
+        # Make a receiver
+        receiver = DatabaseReceiver()
+        # Connect it, and make the models
+        signals.m2m_changed.connect(receiver=receiver)
+
+        b = Book.objects.create(title="Pro Django",
+                                published=datetime.date(2008, 12, 16))
+
+        p = Person.objects.create(name="Marty Alchin")
+
+        # Test addition
+        b.authors.add(p)
+        self.assertEqual(receiver._database, DEFAULT_DB_ALIAS)
+        self._write_to_other()
+        b.authors.add(p)
+        self._write_to_default()
+        self.assertEqual(receiver._database, "other")
+
+        # Test removal
+        b.authors.remove(p)
+        self.assertEqual(receiver._database, DEFAULT_DB_ALIAS)
+        self._write_to_other()
+        b.authors.remove(p)
+        self._write_to_default()
+        self.assertEqual(receiver._database, "other")
+
+        # Test addition in reverse
+        p.book_set.add(b)
+        self.assertEqual(receiver._database, DEFAULT_DB_ALIAS)
+        self._write_to_other()
+        p.book_set.add(b)
+        self._write_to_default()
+        self.assertEqual(receiver._database, "other")
+
+        # Test clearing
+        b.authors.clear()
+        self.assertEqual(receiver._database, DEFAULT_DB_ALIAS)
+        self._write_to_other()
+        b.authors.clear()
+        self._write_to_default()
+        self.assertEqual(receiver._database, "other")