[1.8.x] Fixed #25666 -- Fixed the exact lookup of ArrayField.

Backport of 263b3d2ba132ea443193dc0b728741317742c8d3 from master

3 files changed, 95 insertions, 3 deletions

diff --git a/django/contrib/postgres/fields/array.py b/django/contrib/postgres/fields/array.py
index 5d49d49e22..87760613fb 100644
--- a/django/contrib/postgres/fields/array.py
+++ b/django/contrib/postgres/fields/array.py
@@ -5,6 +5,7 @@ from django.contrib.postgres.forms import SimpleArrayField
 from django.contrib.postgres.validators import ArrayMaxLengthValidator
 from django.core import checks, exceptions
 from django.db.models import Field, IntegerField, Transform
+from django.db.models.lookups import Exact
 from django.utils import six
 from django.utils.translation import string_concat, ugettext_lazy as _
 
@@ -162,7 +163,7 @@ class ArrayField(Field):
 class ArrayContains(lookups.DataContains):
     def as_sql(self, qn, connection):
         sql, params = super(ArrayContains, self).as_sql(qn, connection)
-        sql += '::%s' % self.lhs.output_field.db_type(connection)
+        sql = '%s::%s' % (sql, self.lhs.output_field.db_type(connection))
         return sql, params
 
 
@@ -170,7 +171,15 @@ class ArrayContains(lookups.DataContains):
 class ArrayContainedBy(lookups.ContainedBy):
     def as_sql(self, qn, connection):
         sql, params = super(ArrayContainedBy, self).as_sql(qn, connection)
-        sql += '::%s' % self.lhs.output_field.db_type(connection)
+        sql = '%s::%s' % (sql, self.lhs.output_field.db_type(connection))
+        return sql, params
+
+
+@ArrayField.register_lookup
+class ArrayExact(Exact):
+    def as_sql(self, qn, connection):
+        sql, params = super(ArrayExact, self).as_sql(qn, connection)
+        sql = '%s::%s' % (sql, self.lhs.output_field.db_type(connection))
         return sql, params
 
 
@@ -178,7 +187,7 @@ class ArrayContainedBy(lookups.ContainedBy):
 class ArrayOverlap(lookups.Overlap):
     def as_sql(self, qn, connection):
         sql, params = super(ArrayOverlap, self).as_sql(qn, connection)
-        sql += '::%s' % self.lhs.output_field.db_type(connection)
+        sql = '%s::%s' % (sql, self.lhs.output_field.db_type(connection))
         return sql, params
 
 
diff --git a/docs/releases/1.8.7.txt b/docs/releases/1.8.7.txt
index f73d53e799..acc82f1581 100644
--- a/docs/releases/1.8.7.txt
+++ b/docs/releases/1.8.7.txt
@@ -34,3 +34,5 @@ Bugfixes
 * Fixed serialization of
   :class:`~django.contrib.postgres.fields.DateRangeField` and
   :class:`~django.contrib.postgres.fields.DateTimeRangeField` (:ticket:`24937`).
+
+* Fixed the exact lookup of ``ArrayField`` (:ticket:`25666`).
diff --git a/tests/postgres_tests/test_array.py b/tests/postgres_tests/test_array.py
index d85c0f58ec..fb7eb16da2 100644
--- a/tests/postgres_tests/test_array.py
+++ b/tests/postgres_tests/test_array.py
@@ -110,6 +110,20 @@ class TestQuerying(TestCase):
             self.objs[:1]
         )
 
+    def test_exact_charfield(self):
+        instance = CharArrayModel.objects.create(field=['text'])
+        self.assertSequenceEqual(
+            CharArrayModel.objects.filter(field=['text']),
+            [instance]
+        )
+
+    def test_exact_nested(self):
+        instance = NestedIntegerArrayModel.objects.create(field=[[1, 2], [3, 4]])
+        self.assertSequenceEqual(
+            NestedIntegerArrayModel.objects.filter(field=[[1, 2], [3, 4]]),
+            [instance]
+        )
+
     def test_isnull(self):
         self.assertSequenceEqual(
             NullableIntegerArrayModel.objects.filter(field__isnull=True),
@@ -232,6 +246,73 @@ class TestQuerying(TestCase):
         )
 
 
+class TestDateTimeExactQuerying(TestCase):
+
+    def setUp(self):
+        now = timezone.now()
+        self.datetimes = [now]
+        self.dates = [now.date()]
+        self.times = [now.time()]
+        self.objs = [
+            DateTimeArrayModel.objects.create(
+                datetimes=self.datetimes,
+                dates=self.dates,
+                times=self.times,
+            )
+        ]
+
+    def test_exact_datetimes(self):
+        self.assertSequenceEqual(
+            DateTimeArrayModel.objects.filter(datetimes=self.datetimes),
+            self.objs
+        )
+
+    def test_exact_dates(self):
+        self.assertSequenceEqual(
+            DateTimeArrayModel.objects.filter(dates=self.dates),
+            self.objs
+        )
+
+    def test_exact_times(self):
+        self.assertSequenceEqual(
+            DateTimeArrayModel.objects.filter(times=self.times),
+            self.objs
+        )
+
+
+class TestOtherTypesExactQuerying(TestCase):
+
+    def setUp(self):
+        self.ips = ['192.168.0.1', '::1']
+        self.uuids = [uuid.uuid4()]
+        self.decimals = [decimal.Decimal(1.25), 1.75]
+        self.objs = [
+            OtherTypesArrayModel.objects.create(
+                ips=self.ips,
+                uuids=self.uuids,
+                decimals=self.decimals,
+            )
+        ]
+
+    def test_exact_ip_addresses(self):
+        self.assertSequenceEqual(
+            OtherTypesArrayModel.objects.filter(ips=self.ips),
+            self.objs
+        )
+
+    def test_exact_uuids(self):
+        self.assertSequenceEqual(
+            OtherTypesArrayModel.objects.filter(uuids=self.uuids),
+            self.objs
+        )
+
+    def test_exact_decimals(self):
+        self.assertSequenceEqual(
+            OtherTypesArrayModel.objects.filter(decimals=self.decimals),
+            self.objs
+        )
+
+
 class TestChecks(TestCase):
 
     def test_field_checks(self):