[2.0.x] Fixed #29054 -- Fixed a regression where a queryset that annotates with geometry objects crashes.

Made GEOSGeometryBase hashable.
Regression in 19b2dfd1bfe7fd716dd3d8bfa5f972070d83b42f.

Thanks Tim Graham for the review.
Backport of b002a032f90b8cd228cfcee6c88cd238a8191cc0 from master

4 files changed, 35 insertions, 1 deletions

diff --git a/django/contrib/gis/geos/geometry.py b/django/contrib/gis/geos/geometry.py
index bcda25fa2f..1ebecc864b 100644
--- a/django/contrib/gis/geos/geometry.py
+++ b/django/contrib/gis/geos/geometry.py
@@ -144,6 +144,9 @@ class GEOSGeometryBase(GEOSBase):
                 return False
         return isinstance(other, GEOSGeometry) and self.srid == other.srid and self.equals_exact(other)
 
+    def __hash__(self):
+        return hash((self.srid, self.wkt))
+
     # ### Geometry set-like operations ###
     # Thanks to Sean Gillies for inspiration:
     #  http://lists.gispython.org/pipermail/community/2007-July/001034.html
diff --git a/docs/releases/2.0.2.txt b/docs/releases/2.0.2.txt
index 4a06ccb792..06968d4ba3 100644
--- a/docs/releases/2.0.2.txt
+++ b/docs/releases/2.0.2.txt
@@ -17,3 +17,6 @@ Bugfixes
 
 * Fixed regression in the use of ``QuerySet.values_list(..., flat=True)``
   followed by ``annotate()`` (:ticket:`29067`).
+
+* Fixed a regression where a queryset that annotates with geometry objects
+  crashes (:ticket:`29054`).
diff --git a/tests/gis_tests/geoapp/test_expressions.py b/tests/gis_tests/geoapp/test_expressions.py
index 496e6b58ce..2d0ebbcae0 100644
--- a/tests/gis_tests/geoapp/test_expressions.py
+++ b/tests/gis_tests/geoapp/test_expressions.py
@@ -3,10 +3,11 @@ from unittest import skipUnless
 from django.contrib.gis.db.models import F, GeometryField, Value, functions
 from django.contrib.gis.geos import Point, Polygon
 from django.db import connection
+from django.db.models import Count
 from django.test import TestCase, skipUnlessDBFeature
 
 from ..utils import postgis
-from .models import City, ManyPointModel
+from .models import City, ManyPointModel, MultiFields
 
 
 class GeoExpressionsTests(TestCase):
@@ -48,6 +49,17 @@ class GeoExpressionsTests(TestCase):
             obj.refresh_from_db()
             self.assertTrue(obj.point3.equals_exact(p1.transform(3857, clone=True), 0.1))
 
+    def test_multiple_annotation(self):
+        multi_field = MultiFields.objects.create(
+            point=Point(1, 1),
+            city=City.objects.get(name='Houston'),
+            poly=Polygon(((1, 1), (1, 2), (2, 2), (2, 1), (1, 1))),
+        )
+        qs = City.objects.values('name').annotate(
+            distance=functions.Distance('multifields__point', multi_field.city.point),
+        ).annotate(count=Count('multifields'))
+        self.assertTrue(qs.first())
+
     @skipUnlessDBFeature('has_Translate_function')
     def test_update_with_expression(self):
         city = City.objects.create(point=Point(1, 1, srid=4326))
diff --git a/tests/gis_tests/geos_tests/test_geos.py b/tests/gis_tests/geos_tests/test_geos.py
index 0db98285fa..66574f16d1 100644
--- a/tests/gis_tests/geos_tests/test_geos.py
+++ b/tests/gis_tests/geos_tests/test_geos.py
@@ -187,6 +187,22 @@ class GEOSTest(SimpleTestCase, TestDataMixin):
             self.assertNotEqual(g, {'foo': 'bar'})
             self.assertNotEqual(g, False)
 
+    def test_hash(self):
+        point_1 = Point(5, 23)
+        point_2 = Point(5, 23, srid=4326)
+        point_3 = Point(5, 23, srid=32632)
+        multipoint_1 = MultiPoint(point_1, srid=4326)
+        multipoint_2 = MultiPoint(point_2)
+        multipoint_3 = MultiPoint(point_3)
+        self.assertNotEqual(hash(point_1), hash(point_2))
+        self.assertNotEqual(hash(point_1), hash(point_3))
+        self.assertNotEqual(hash(point_2), hash(point_3))
+        self.assertNotEqual(hash(multipoint_1), hash(multipoint_2))
+        self.assertEqual(hash(multipoint_2), hash(multipoint_3))
+        self.assertNotEqual(hash(multipoint_1), hash(point_1))
+        self.assertNotEqual(hash(multipoint_2), hash(point_2))
+        self.assertNotEqual(hash(multipoint_3), hash(point_3))
+
     def test_eq_with_srid(self):
         "Testing non-equivalence with different srids."
         p0 = Point(5, 23)