From 155b31d4ec138664d62665eb2d8a442469045b78 Mon Sep 17 00:00:00 2001
From: Raphael Michel <mail@raphaelmichel.de>
Date: Tue, 7 Aug 2018 18:08:39 +0200
Subject: [PATCH] Fixed #29648 -- Fixed crash when using subqueries inside
 datetime truncation functions.

---
 django/db/models/functions/datetime.py |  2 --
 tests/db_functions/models.py           |  1 +
 tests/db_functions/test_datetime.py    | 36 ++++++++++++++++++++++++--
 3 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/django/db/models/functions/datetime.py b/django/db/models/functions/datetime.py
index 74b88b77ca..1876aa7d5c 100644
--- a/django/db/models/functions/datetime.py
+++ b/django/db/models/functions/datetime.py
@@ -164,8 +164,6 @@ class TruncBase(TimezoneMixin, Transform):
 
     def as_sql(self, compiler, connection):
         inner_sql, inner_params = compiler.compile(self.lhs)
-        # Escape any params because trunc_sql will format the string.
-        inner_sql = inner_sql.replace('%s', '%%s')
         if isinstance(self.output_field, DateTimeField):
             tzname = self.get_tzname()
             sql = connection.ops.datetime_trunc_sql(self.kind, inner_sql, tzname)
diff --git a/tests/db_functions/models.py b/tests/db_functions/models.py
index c31de39b85..083655e80f 100644
--- a/tests/db_functions/models.py
+++ b/tests/db_functions/models.py
@@ -32,6 +32,7 @@ class Fan(models.Model):
     name = models.CharField(max_length=50)
     age = models.PositiveSmallIntegerField(default=30)
     author = models.ForeignKey(Author, models.CASCADE, related_name='fans')
+    fan_since = models.DateTimeField(null=True, blank=True)
 
     def __str__(self):
         return self.name
diff --git a/tests/db_functions/test_datetime.py b/tests/db_functions/test_datetime.py
index dc4c911ab9..07b6b0438a 100644
--- a/tests/db_functions/test_datetime.py
+++ b/tests/db_functions/test_datetime.py
@@ -3,7 +3,9 @@ from datetime import datetime, timedelta
 import pytz
 
 from django.conf import settings
-from django.db.models import DateField, DateTimeField, IntegerField, TimeField
+from django.db.models import (
+    DateField, DateTimeField, IntegerField, Max, OuterRef, Subquery, TimeField,
+)
 from django.db.models.functions import (
     Extract, ExtractDay, ExtractHour, ExtractMinute, ExtractMonth,
     ExtractQuarter, ExtractSecond, ExtractWeek, ExtractWeekDay, ExtractYear,
@@ -15,7 +17,7 @@ from django.test import (
 )
 from django.utils import timezone
 
-from .models import DTModel
+from .models import Author, DTModel, Fan
 
 
 def truncate_to(value, kind, tzinfo=None):
@@ -854,6 +856,36 @@ class DateFunctionTests(TestCase):
         with self.assertRaisesMessage(ValueError, "Cannot truncate DateField 'start_date' to DateTimeField"):
             list(DTModel.objects.annotate(truncated=TruncSecond('start_date', output_field=DateField())))
 
+    def test_trunc_subquery_with_parameters(self):
+        author_1 = Author.objects.create(name='J. R. R. Tolkien')
+        author_2 = Author.objects.create(name='G. R. R. Martin')
+        fan_since_1 = datetime(2016, 2, 3, 15, 0, 0)
+        fan_since_2 = datetime(2015, 2, 3, 15, 0, 0)
+        fan_since_3 = datetime(2017, 2, 3, 15, 0, 0)
+        if settings.USE_TZ:
+            fan_since_1 = timezone.make_aware(fan_since_1, is_dst=False)
+            fan_since_2 = timezone.make_aware(fan_since_2, is_dst=False)
+            fan_since_3 = timezone.make_aware(fan_since_3, is_dst=False)
+        Fan.objects.create(author=author_1, name='Tom', fan_since=fan_since_1)
+        Fan.objects.create(author=author_1, name='Emma', fan_since=fan_since_2)
+        Fan.objects.create(author=author_2, name='Isabella', fan_since=fan_since_3)
+
+        inner = Fan.objects.filter(
+            author=OuterRef('pk'),
+            name__in=('Emma', 'Isabella', 'Tom')
+        ).values('author').annotate(newest_fan=Max('fan_since')).values('newest_fan')
+        outer = Author.objects.annotate(
+            newest_fan_year=TruncYear(Subquery(inner, output_field=DateTimeField()))
+        )
+        tz = pytz.UTC if settings.USE_TZ else None
+        self.assertSequenceEqual(
+            outer.order_by('name').values('name', 'newest_fan_year'),
+            [
+                {'name': 'G. R. R. Martin', 'newest_fan_year': datetime(2017, 1, 1, 0, 0, tzinfo=tz)},
+                {'name': 'J. R. R. Tolkien', 'newest_fan_year': datetime(2016, 1, 1, 0, 0, tzinfo=tz)},
+            ]
+        )
+
 
 @override_settings(USE_TZ=True, TIME_ZONE='UTC')
 class DateFunctionWithTimeZoneTests(DateFunctionTests):