Fixed #2936, #6500 -- Added a __hash__() method to Models (since we implement our own __eq__ method).

git-svn-id: http://code.djangoproject.com/svn/django/trunk@7132 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/base.py

@@ -135,6 +135,9 @@ class Model(object):
     def __ne__(self, other):
         return not self.__eq__(other)
 
+    def __hash__(self):
+        return hash(self._get_pk_val())
+
     def __init__(self, *args, **kwargs):
         dispatcher.send(signal=signals.pre_init, sender=self.__class__, args=args, kwargs=kwargs)
 

tests/modeltests/basic/models.py

@@ -5,6 +5,11 @@
 This is a basic model with only two non-primary-key fields.
 """
 
+try:
+    set
+except NameError:
+    from sets import Set as set
+
 from django.db import models
 
 class Article(models.Model):
@@ -389,4 +394,10 @@ year, including Jan. 1 and Dec. 31.
 >>> a.save()
 >>> Article.objects.get(pk=a.id).headline
 u'\u6797\u539f \u3081\u3050\u307f'
+
+# Model instances have a hash function, so they can be used in sets or as
+# dictionary keys. Two models compare as equal if their primary keys are equal.
+>>> s = set([a10, a11, a12])
+>>> Article.objects.get(headline='Article 11') in s
+True
 """