[4.2.x] Fixed #36098 -- Fixed validate_ipv6_address()/validate_ipv46_address() crash for non-string values.

Regression in ca2be7724e1244a4cb723de40a070f873c6e94bf.

Backport of b3c5830769d8a5dbf2f974da7116fe503c9454d9 from main.

5 files changed, 50 insertions, 4 deletions

diff --git a/django/utils/ipv6.py b/django/utils/ipv6.py
index de41a97f72..487fa7b1e1 100644
--- a/django/utils/ipv6.py
+++ b/django/utils/ipv6.py
@@ -49,12 +49,14 @@ def clean_ipv6_address(
     return str(addr)
 
 
-def is_valid_ipv6_address(ip_str):
+def is_valid_ipv6_address(ip_addr):
     """
-    Return whether or not the `ip_str` string is a valid IPv6 address.
+    Return whether the `ip_addr` object is a valid IPv6 address.
     """
+    if isinstance(ip_addr, ipaddress.IPv6Address):
+        return True
     try:
-        _ipv6_address_from_str(ip_str)
-    except ValueError:
+        _ipv6_address_from_str(ip_addr)
+    except (TypeError, ValueError):
         return False
     return True
diff --git a/docs/releases/4.2.19.txt b/docs/releases/4.2.19.txt
new file mode 100644
index 0000000000..91bc8e5842
--- /dev/null
+++ b/docs/releases/4.2.19.txt
@@ -0,0 +1,14 @@
+===========================
+Django 4.2.19 release notes
+===========================
+
+*Expected February 5, 2025*
+
+Django 4.2.19 fixes a regression in 4.2.18.
+
+Bugfixes
+========
+
+* Fixed a regression in Django 4.2.18 that caused ``validate_ipv6_address()``
+  and ``validate_ipv46_address()`` to crash when handling non-string values
+  (:ticket:`36098`).
diff --git a/docs/releases/index.txt b/docs/releases/index.txt
index ec69c8e414..034821f151 100644
--- a/docs/releases/index.txt
+++ b/docs/releases/index.txt
@@ -26,6 +26,7 @@ versions of the documentation contain the release notes for any later releases.
 .. toctree::
    :maxdepth: 1
 
+   4.2.19
    4.2.18
    4.2.17
    4.2.16
diff --git a/tests/utils_tests/test_ipv6.py b/tests/utils_tests/test_ipv6.py
index 2d06507fa1..3734222318 100644
--- a/tests/utils_tests/test_ipv6.py
+++ b/tests/utils_tests/test_ipv6.py
@@ -1,5 +1,7 @@
 import traceback
+from decimal import Decimal
 from io import StringIO
+from ipaddress import IPv6Address
 
 from django.core.exceptions import ValidationError
 from django.test import SimpleTestCase
@@ -24,6 +26,16 @@ class TestUtilsIPv6(SimpleTestCase):
         self.assertTrue(is_valid_ipv6_address("::ffff:254.42.16.14"))
         self.assertTrue(is_valid_ipv6_address("::ffff:0a0a:0a0a"))
 
+    def test_validates_correct_with_ipv6_instance(self):
+        cases = [
+            IPv6Address("::ffff:2.125.160.216"),
+            IPv6Address("fe80::1"),
+            IPv6Address("::"),
+        ]
+        for case in cases:
+            with self.subTest(case=case):
+                self.assertIs(is_valid_ipv6_address(case), True)
+
     def test_validates_incorrect_plain_address(self):
         self.assertFalse(is_valid_ipv6_address("foo"))
         self.assertFalse(is_valid_ipv6_address("127.0.0.1"))
@@ -46,6 +58,12 @@ class TestUtilsIPv6(SimpleTestCase):
         self.assertFalse(is_valid_ipv6_address("::999.42.16.14"))
         self.assertFalse(is_valid_ipv6_address("::zzzz:0a0a"))
 
+    def test_validates_incorrect_with_non_string(self):
+        cases = [None, [], {}, (), Decimal("2.46"), 192.168, 42]
+        for case in cases:
+            with self.subTest(case=case):
+                self.assertIs(is_valid_ipv6_address(case), False)
+
     def test_cleans_plain_address(self):
         self.assertEqual(clean_ipv6_address("DEAD::0:BEEF"), "dead::beef")
         self.assertEqual(
diff --git a/tests/validators/tests.py b/tests/validators/tests.py
index e99baab862..f4ab7fbece 100644
--- a/tests/validators/tests.py
+++ b/tests/validators/tests.py
@@ -1,3 +1,4 @@
+import ipaddress
 import re
 import types
 from datetime import datetime, timedelta
@@ -381,15 +382,25 @@ TEST_DATA = [
     (validate_ipv6_address, "fe80::1", None),
     (validate_ipv6_address, "::1", None),
     (validate_ipv6_address, "1:2:3:4:5:6:7:8", None),
+    (validate_ipv6_address, ipaddress.IPv6Address("::ffff:2.125.160.216"), None),
+    (validate_ipv6_address, ipaddress.IPv6Address("fe80::1"), None),
+    (validate_ipv6_address, Decimal("33.1"), ValidationError),
+    (validate_ipv6_address, 9.22, ValidationError),
     (validate_ipv6_address, "1:2", ValidationError),
     (validate_ipv6_address, "::zzz", ValidationError),
     (validate_ipv6_address, "12345::", ValidationError),
     (validate_ipv46_address, "1.1.1.1", None),
     (validate_ipv46_address, "255.0.0.0", None),
     (validate_ipv46_address, "0.0.0.0", None),
+    (validate_ipv46_address, ipaddress.IPv4Address("1.1.1.1"), None),
+    (validate_ipv46_address, ipaddress.IPv4Address("255.0.0.0"), None),
     (validate_ipv46_address, "fe80::1", None),
     (validate_ipv46_address, "::1", None),
     (validate_ipv46_address, "1:2:3:4:5:6:7:8", None),
+    (validate_ipv46_address, ipaddress.IPv6Address("::ffff:2.125.160.216"), None),
+    (validate_ipv46_address, ipaddress.IPv6Address("fe80::1"), None),
+    (validate_ipv46_address, Decimal("33.1"), ValidationError),
+    (validate_ipv46_address, 9.22, ValidationError),
     (validate_ipv46_address, "256.1.1.1", ValidationError),
     (validate_ipv46_address, "25.1.1.", ValidationError),
     (validate_ipv46_address, "25,1,1,1", ValidationError),