From 6f185a53a2a7acad0ad8383267942d554527688a Mon Sep 17 00:00:00 2001
From: Mariusz Felisiak <felisiak.mariusz@gmail.com>
Date: Mon, 7 Feb 2022 20:34:21 +0100
Subject: [PATCH] Refs #33482 -- Fixed QuerySet selecting and filtering againts
 negated Exists() with empty queryset.

Regression in b7d1da5a62fe4141beff2bfea565f7ef0038c94c.
---
 django/db/models/expressions.py | 5 ++++-
 tests/expressions/tests.py      | 8 ++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/django/db/models/expressions.py b/django/db/models/expressions.py
index c71970636c..f31ff4d3df 100644
--- a/django/db/models/expressions.py
+++ b/django/db/models/expressions.py
@@ -1221,7 +1221,10 @@ class Exists(Subquery):
             )
         except EmptyResultSet:
             if self.negated:
-                return '', ()
+                features = compiler.connection.features
+                if not features.supports_boolean_expr_in_select_clause:
+                    return "1=1", ()
+                return compiler.compile(Value(True))
             raise
         if self.negated:
             sql = 'NOT {}'.format(sql)
diff --git a/tests/expressions/tests.py b/tests/expressions/tests.py
index dcde321c57..1aa0049cbe 100644
--- a/tests/expressions/tests.py
+++ b/tests/expressions/tests.py
@@ -1918,6 +1918,14 @@ class ExistsTests(TestCase):
         )
         self.assertSequenceEqual(qs, [manager])
 
+    def test_select_negated_empty_exists(self):
+        manager = Manager.objects.create()
+        qs = Manager.objects.annotate(
+            not_exists=~Exists(Manager.objects.none())
+        ).filter(pk=manager.pk)
+        self.assertSequenceEqual(qs, [manager])
+        self.assertIs(qs.get().not_exists, True)
+
 
 class FieldTransformTests(TestCase):