From 91be6e1818c3cb70890608491eea79e984f98ede Mon Sep 17 00:00:00 2001
From: Kacper Wolkiewicz <45897171+wolkiewiczk@users.noreply.github.com>
Date: Wed, 31 May 2023 12:57:40 +0200
Subject: [PATCH] Fixed #34606 -- Fixed Right() function with zero length on
 Oracle and SQLite.

---
 AUTHORS                               |  1 +
 django/db/models/functions/text.py    |  4 +++-
 tests/db_functions/text/test_right.py | 18 +++++++++++++++++-
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/AUTHORS b/AUTHORS
index 95f24762ee..d5e3af2310 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -545,6 +545,7 @@ answer newbie questions, and generally made Django that much better:
     Justin Michalicek <jmichalicek@gmail.com>
     Justin Myles Holmes <justin@slashrootcafe.com>
     Jyrki Pulliainen <jyrki.pulliainen@gmail.com>
+    Kacper Wolkiewicz <kac.wolkiewicz@gmail.com>
     Kadesarin Sanjek
     Kapil Bansal <kapilbansal.gbpecdelhi@gmail.com>
     Karderio <karderio@gmail.com>
diff --git a/django/db/models/functions/text.py b/django/db/models/functions/text.py
index fba2840c4b..2b49f54328 100644
--- a/django/db/models/functions/text.py
+++ b/django/db/models/functions/text.py
@@ -276,7 +276,9 @@ class Right(Left):
 
     def get_substr(self):
         return Substr(
-            self.source_expressions[0], self.source_expressions[1] * Value(-1)
+            self.source_expressions[0],
+            self.source_expressions[1] * Value(-1),
+            self.source_expressions[1],
         )
 
 
diff --git a/tests/db_functions/text/test_right.py b/tests/db_functions/text/test_right.py
index 126f1583a5..93d929f9e0 100644
--- a/tests/db_functions/text/test_right.py
+++ b/tests/db_functions/text/test_right.py
@@ -1,5 +1,6 @@
+from django.db import connection
 from django.db.models import IntegerField, Value
-from django.db.models.functions import Lower, Right
+from django.db.models.functions import Length, Lower, Right
 from django.test import TestCase
 
 from ..models import Author
@@ -26,6 +27,21 @@ class RightTests(TestCase):
         with self.assertRaisesMessage(ValueError, "'length' must be greater than 0"):
             Author.objects.annotate(raises=Right("name", 0))
 
+    def test_zero_length(self):
+        Author.objects.create(name="Tom", alias="tom")
+        authors = Author.objects.annotate(
+            name_part=Right("name", Length("name") - Length("alias"))
+        )
+        self.assertQuerySetEqual(
+            authors.order_by("name"),
+            [
+                "mith",
+                "" if connection.features.interprets_empty_strings_as_nulls else None,
+                "",
+            ],
+            lambda a: a.name_part,
+        )
+
     def test_expressions(self):
         authors = Author.objects.annotate(
             name_part=Right("name", Value(3, output_field=IntegerField()))