Fixed #16302 -- Ensure contrib.comments is IPv6 capable

Changed the ip_address field for Comment to GenericIPAddressField. Added
instructions to the release notes on how to update the schema of existing
databases.

django/contrib/comments/models.py

@@ -60,7 +60,7 @@ class Comment(BaseCommentAbstractModel):
 
     # Metadata about the comment
     submit_date = models.DateTimeField(_('date/time submitted'), default=None)
-    ip_address = models.IPAddressField(_('IP address'), blank=True, null=True)
+    ip_address = models.GenericIPAddressField(_('IP address'), unpack_ipv4=True, blank=True, null=True)
     is_public = models.BooleanField(_('is public'), default=True,
                     help_text=_('Uncheck this box to make the comment effectively ' \
                                 'disappear from the site.'))

docs/releases/1.6.txt

@@ -149,6 +149,30 @@ Backwards incompatible changes in 1.6
     {{ title }}{# Translators: Extracted and associated with 'Welcome' below #}
     <h1>{% trans "Welcome" %}</h1>
 
+* The :doc:`comments </ref/contrib/comments/index>` app now uses a ``GenericIPAddressField``
+  for storing commenters' IP addresses, to support comments submitted from IPv6 addresses.
+  Until now, it stored them in an ``IPAddressField``, which is only meant to support IPv4.
+  When saving a comment made from an IPv6 address, the address would be silently truncated
+  on MySQL databases, and raise an exception on Oracle.
+  You will need to change the column type in your database to benefit from this change.
+
+  For MySQL, execute this query on your project's database:
+
+  .. code-block:: sql
+
+    ALTER TABLE django_comments MODIFY ip_address VARCHAR(39);
+
+  For Oracle, execute this query:
+
+  .. code-block:: sql
+
+    ALTER TABLE DJANGO_COMMENTS MODIFY (ip_address VARCHAR2(39));
+
+  If you do not apply this change, the behaviour is unchanged: on MySQL, IPv6 addresses
+  are silently truncated; on Oracle, an exception is generated. No database
+  change is needed for SQLite or PostgreSQL databases.
+
+
 .. warning::
 
     In addition to the changes outlined in this section, be sure to review the

tests/regressiontests/comment_tests/tests/comment_view_tests.py

@@ -101,13 +101,43 @@ def testDebugCommentErrors(self):
         settings.DEBUG = olddebug
 
     def testCreateValidComment(self):
+        address = "1.2.3.4"
         a = Article.objects.get(pk=1)
         data = self.getValidData(a)
-        self.response = self.client.post("/post/", data, REMOTE_ADDR="1.2.3.4")
+        self.response = self.client.post("/post/", data, REMOTE_ADDR=address)
         self.assertEqual(self.response.status_code, 302)
         self.assertEqual(Comment.objects.count(), 1)
         c = Comment.objects.all()[0]
-        self.assertEqual(c.ip_address, "1.2.3.4")
+        self.assertEqual(c.ip_address, address)
+        self.assertEqual(c.comment, "This is my comment")
+
+    def testCreateValidCommentIPv6(self):
+        """
+        Test creating a valid comment with a long IPv6 address.
+        Note that this test should fail when Comment.ip_address is an IPAddress instead of a GenericIPAddress,
+        but does not do so on SQLite or PostgreSQL, because they use the TEXT and INET types, which already
+        allow storing an IPv6 address internally.
+        """
+        address = "2a02::223:6cff:fe8a:2e8a"
+        a = Article.objects.get(pk=1)
+        data = self.getValidData(a)
+        self.response = self.client.post("/post/", data, REMOTE_ADDR=address)
+        self.assertEqual(self.response.status_code, 302)
+        self.assertEqual(Comment.objects.count(), 1)
+        c = Comment.objects.all()[0]
+        self.assertEqual(c.ip_address, address)
+        self.assertEqual(c.comment, "This is my comment")
+
+    def testCreateValidCommentIPv6Unpack(self):
+        address = "::ffff:18.52.18.52"
+        a = Article.objects.get(pk=1)
+        data = self.getValidData(a)
+        self.response = self.client.post("/post/", data, REMOTE_ADDR=address)
+        self.assertEqual(self.response.status_code, 302)
+        self.assertEqual(Comment.objects.count(), 1)
+        c = Comment.objects.all()[0]
+        # We trim the '::ffff:' bit off because it is an IPv4 addr
+        self.assertEqual(c.ip_address, address[7:])
         self.assertEqual(c.comment, "This is my comment")
 
     def testPostAsAuthenticatedUser(self):