Fixed #4879 -- Added 'created' arg to post_save signal. This is True is a new object is created. Patch from George Vilches.

Fully backwards compatible, because signal receivers do not have to be able to accept all the arguments (thankyou, robust_apply()).


git-svn-id: http://code.djangoproject.com/svn/django/trunk@6269 bcc190cf-cafb-0310-a4f2-bffc1f526a37

AUTHORS

@@ -296,6 +296,7 @@ answer newbie questions, and generally made Django that much better:
     Amit Upadhyay
     Geert Vanderkelen
     viestards.lists@gmail.com
+    George Vilches <gav@thataddress.com>
     Vlado <vlado@labath.org>
     Milton Waddams
     wam-djangobug@wamber.net

django/db/models/base.py

@@ -247,6 +247,7 @@ class Model(object):
                     qn(self._meta.order_with_respect_to.column))
                 cursor.execute(subsel, (getattr(self, self._meta.order_with_respect_to.attname),))
                 db_values.append(cursor.fetchone()[0])
+            record_exists = False
             if db_values:
                 cursor.execute("INSERT INTO %s (%s) VALUES (%s)" % \
                     (qn(self._meta.db_table), ','.join(field_names),
@@ -261,7 +262,8 @@ class Model(object):
         transaction.commit_unless_managed()
 
         # Run any post-save hooks.
-        dispatcher.send(signal=signals.post_save, sender=self.__class__, instance=self)
+        dispatcher.send(signal=signals.post_save, sender=self.__class__,
+                instance=self, created=(not record_exists))
 
     save.alters_data = True
 

tests/modeltests/signals/models.py

@@ -0,0 +1,85 @@
+"""
+Testing signals before/after saving and deleting.
+"""
+
+from django.db import models
+from django.dispatch import dispatcher
+
+class Person(models.Model):
+    first_name = models.CharField(max_length=20)
+    last_name = models.CharField(max_length=20)
+
+    def __unicode__(self):
+        return u"%s %s" % (self.first_name, self.last_name)
+
+
+def pre_save_test(sender, instance, **kwargs):
+    print 'pre_save signal,', instance
+
+def post_save_test(sender, instance, **kwargs):
+    print 'post_save signal,', instance
+    if 'created' in kwargs:
+        if kwargs['created']:
+            print 'Is created'
+        else:
+            print 'Is updated'
+
+def pre_delete_test(sender, instance, **kwargs):
+    print 'pre_delete signal,', instance
+    print 'instance.id is not None: %s' % (instance.id != None)  
+
+def post_delete_test(sender, instance, **kwargs):
+    print 'post_delete signal,', instance
+    print 'instance.id is None: %s' % (instance.id == None)  
+
+__test__ = {'API_TESTS':"""
+>>> dispatcher.connect(pre_save_test, signal=models.signals.pre_save)
+>>> dispatcher.connect(post_save_test, signal=models.signals.post_save)
+>>> dispatcher.connect(pre_delete_test, signal=models.signals.pre_delete)
+>>> dispatcher.connect(post_delete_test, signal=models.signals.post_delete)
+
+>>> p1 = Person(first_name='John', last_name='Smith')
+>>> p1.save()
+pre_save signal, John Smith
+post_save signal, John Smith
+Is created
+
+>>> p1.first_name = 'Tom'
+>>> p1.save()
+pre_save signal, Tom Smith
+post_save signal, Tom Smith
+Is updated
+
+>>> p1.delete()
+pre_delete signal, Tom Smith
+instance.id is not None: True
+post_delete signal, Tom Smith
+instance.id is None: True
+
+>>> p2 = Person(first_name='James', last_name='Jones')
+>>> p2.id = 99999
+>>> p2.save()
+pre_save signal, James Jones
+post_save signal, James Jones
+Is created
+
+>>> p2.id = 99998
+>>> p2.save()
+pre_save signal, James Jones
+post_save signal, James Jones
+Is created
+
+>>> p2.delete()
+pre_delete signal, James Jones
+instance.id is not None: True
+post_delete signal, James Jones
+instance.id is None: True
+
+>>> Person.objects.all()
+[<Person: James Jones>]
+
+>>> dispatcher.disconnect(post_delete_test, signal=models.signals.post_delete)
+>>> dispatcher.disconnect(pre_delete_test, signal=models.signals.pre_delete)
+>>> dispatcher.disconnect(post_save_test, signal=models.signals.post_save)
+>>> dispatcher.disconnect(pre_save_test, signal=models.signals.pre_save)
+"""}