Fixed #13935, added support for using QuerySet.dates across related fields. Thanks to valyagolev for his work on the patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@14461 bcc190cf-cafb-0310-a4f2-bffc1f526a37

5 files changed, 121 insertions, 10 deletions

diff --git a/django/db/models/query.py b/django/db/models/query.py
index 7e91b0fc93..bb62f22f8a 100644
--- a/django/db/models/query.py
+++ b/django/db/models/query.py
@@ -7,7 +7,8 @@ from itertools import izip
 from django.db import connections, router, transaction, IntegrityError
 from django.db.models.aggregates import Aggregate
 from django.db.models.fields import DateField
-from django.db.models.query_utils import Q, select_related_descend, CollectedObjects, CyclicDependency, deferred_class_factory, InvalidQuery
+from django.db.models.query_utils import (Q, select_related_descend,
+    CollectedObjects, CyclicDependency, deferred_class_factory, InvalidQuery)
 from django.db.models import signals, sql
 from django.utils.copycompat import deepcopy
 
@@ -998,12 +999,7 @@ class DateQuerySet(QuerySet):
         self.query.clear_deferred_loading()
         self.query = self.query.clone(klass=sql.DateQuery, setup=True)
         self.query.select = []
-        field = self.model._meta.get_field(self._field_name, many_to_many=False)
-        assert isinstance(field, DateField), "%r isn't a DateField." \
-                % field.name
-        self.query.add_date_select(field, self._kind, self._order)
-        if field.null:
-            self.query.add_filter(('%s__isnull' % field.name, False))
+        self.query.add_date_select(self._field_name, self._kind, self._order)
 
     def _clone(self, klass=None, setup=False, **kwargs):
         c = super(DateQuerySet, self)._clone(klass, False, **kwargs)
diff --git a/django/db/models/sql/subqueries.py b/django/db/models/sql/subqueries.py
index a066dfeca8..932a4429ec 100644
--- a/django/db/models/sql/subqueries.py
+++ b/django/db/models/sql/subqueries.py
@@ -4,6 +4,7 @@ Query subclasses which provide extra functionality beyond simple data retrieval.
 
 from django.core.exceptions import FieldError
 from django.db import connections
+from django.db.models.fields import DateField
 from django.db.models.sql.constants import *
 from django.db.models.sql.datastructures import Date
 from django.db.models.sql.expressions import SQLEvaluator
@@ -184,12 +185,19 @@ class DateQuery(Query):
 
     compiler = 'SQLDateCompiler'
 
-    def add_date_select(self, field, lookup_type, order='ASC'):
+    def add_date_select(self, field_name, lookup_type, order='ASC'):
         """
         Converts the query into a date extraction query.
         """
-        result = self.setup_joins([field.name], self.get_meta(),
-                self.get_initial_alias(), False)
+        result = self.setup_joins(
+            field_name.split(LOOKUP_SEP),
+            self.get_meta(),
+            self.get_initial_alias(),
+            False
+        )
+        field = result[0]
+        assert isinstance(field, DateField), "%r isn't a DateField." \
+                % field.name
         alias = result[3][-1]
         select = Date((alias, field.column), lookup_type)
         self.select = [select]
@@ -199,6 +207,9 @@ class DateQuery(Query):
         self.distinct = True
         self.order_by = order == 'ASC' and [1] or [-1]
 
+        if field.null:
+            self.add_filter(("%s__isnull" % field_name, False))
+
 class AggregateQuery(Query):
     """
     An AggregateQuery takes another query as a parameter to the FROM
diff --git a/tests/regressiontests/dates/__init__.py b/tests/regressiontests/dates/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/tests/regressiontests/dates/__init__.py
diff --git a/tests/regressiontests/dates/models.py b/tests/regressiontests/dates/models.py
new file mode 100644
index 0000000000..e1fc1e74fe
--- /dev/null
+++ b/tests/regressiontests/dates/models.py
@@ -0,0 +1,23 @@
+from django.db import models
+
+
+class Article(models.Model):
+    title = models.CharField(max_length=100)
+    pub_date = models.DateField()
+
+    categories = models.ManyToManyField("Category", related_name="articles")
+
+    def __unicode__(self):
+        return self.title
+
+class Comment(models.Model):
+    article = models.ForeignKey(Article, related_name="comments")
+    text = models.TextField()
+    pub_date = models.DateField()
+    approval_date = models.DateField(null=True)
+
+    def __unicode__(self):
+        return 'Comment to %s (%s)' % (self.article.title, self.pub_date)
+
+class Category(models.Model):
+    name = models.CharField(max_length=255)
diff --git a/tests/regressiontests/dates/tests.py b/tests/regressiontests/dates/tests.py
new file mode 100644
index 0000000000..769d074215
--- /dev/null
+++ b/tests/regressiontests/dates/tests.py
@@ -0,0 +1,81 @@
+from datetime import datetime
+
+from django.test import TestCase
+
+from models import Article, Comment, Category
+
+
+class DatesTests(TestCase):
+    def test_related_model_traverse(self):
+        a1 = Article.objects.create(
+            title="First one",
+            pub_date=datetime(2005, 7, 28),
+        )
+        a2 = Article.objects.create(
+            title="Another one",
+            pub_date=datetime(2010, 7, 28),
+        )
+        a3 = Article.objects.create(
+            title="Third one, in the first day",
+            pub_date=datetime(2005, 7, 28),
+        )
+
+        a1.comments.create(
+            text="Im the HULK!",
+            pub_date=datetime(2005, 7, 28),
+        )
+        a1.comments.create(
+            text="HULK SMASH!",
+            pub_date=datetime(2005, 7, 29),
+        )
+        a2.comments.create(
+            text="LMAO",
+            pub_date=datetime(2010, 7, 28),
+        )
+        a3.comments.create(
+            text="+1",
+            pub_date=datetime(2005, 8, 29),
+        )
+
+        c = Category.objects.create(name="serious-news")
+        c.articles.add(a1, a3)
+
+        self.assertQuerysetEqual(
+            Comment.objects.dates("article__pub_date", "year"), [
+                datetime(2005, 1, 1),
+                datetime(2010, 1, 1),
+            ],
+            lambda d: d,
+        )
+        self.assertQuerysetEqual(
+            Comment.objects.dates("article__pub_date", "month"), [
+                datetime(2005, 7, 1),
+                datetime(2010, 7, 1),
+            ],
+            lambda d: d
+        )
+        self.assertQuerysetEqual(
+            Comment.objects.dates("article__pub_date", "day"), [
+                datetime(2005, 7, 28),
+                datetime(2010, 7, 28),
+            ],
+            lambda d: d
+        )
+        self.assertQuerysetEqual(
+            Article.objects.dates("comments__pub_date", "day"), [
+                datetime(2005, 7, 28),
+                datetime(2005, 7, 29),
+                datetime(2005, 8, 29),
+                datetime(2010, 7, 28),
+            ],
+            lambda d: d
+        )
+        self.assertQuerysetEqual(
+            Article.objects.dates("comments__approval_date", "day"), []
+        )
+        self.assertQuerysetEqual(
+            Category.objects.dates("articles__pub_date", "day"), [
+                datetime(2005, 7, 28),
+            ],
+            lambda d: d,
+        )