ipv4-mapped test fails on python 3.12

[bsmith5uoe]

A test for ipv4-mapped addresses fails on python 3.12 as IPv6Address.__str__ formats it in hex rather than as dotted-quad. See python/cpython@f22bf8e for the commit that changed this behaviour for python 3.13 onwards.

The test could be improved to work on 3.12 by using the ipv4_mapped property instead of relying on the stringification.

======================================================================
FAIL: test_round_trip_ipv4_mapped_address (tests.unit_tests.test_driver.test_network.TestIPv6DataType.test_round_trip_ipv4_mapped_address)
A full round-trip test to ensure serialization and deserialization work together.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/afs/inf.ed.ac.uk/user/b/bsmith5/chclient/clickhouse-connect/.pybuild/cpython3_3.12_clickhouse-connect/build/tests/unit_tests/test_driver/test_network.py", line 87, in test_round_trip_ipv4_mapped_address
    self.assertEqual(str(final_ip), ip_string)
AssertionError: '::ffff:c0a8:101' != '::ffff:192.168.1.1'
- ::ffff:c0a8:101
+ ::ffff:192.168.1.1

----------------------------------------------------------------------
Ran 54 tests in 0.028s

FAILED (failures=1)

Example patch:

From: Benjamin Smith <bsmith5@ed.ac.uk>
Date: Wed, 17 Sep 2025 10:45:36 +0100
Subject: Patch around a test for python 3.12

---
 tests/unit_tests/test_driver/test_network.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tests/unit_tests/test_driver/test_network.py b/tests/unit_tests/test_driver/test_network.py
index 8fa4fbe..af740c5 100644
--- a/tests/unit_tests/test_driver/test_network.py
+++ b/tests/unit_tests/test_driver/test_network.py
@@ -84,7 +84,9 @@ class TestIPv6DataType(unittest.TestCase):
         final_ip = read_result[0]
 
         self.assertIsInstance(final_ip, IPv6Address)
-        self.assertEqual(str(final_ip), ip_string)
+        # ipv4-mapped handling in IPv6Address.__str__ is a 3.13 feature
+        #self.assertEqual(str(final_ip), ip_string)
+        self.assertEqual('::ffff:' + str(final_ip.ipv4_mapped), ip_string)
 
     def test_round_trip_standard_ipv6(self):
         """Ensures a standard IPv6 address can be written and read back correctly."""

[joe-clickhouse]

Hey, thanks for raising this! This is very likely a Python 3.12 patch-level difference. Our GH actions setup always installs the latest available micro release for each minor, so our CI runs end up with the patched behavior for IPv6Address.__str__ on IPv4‑mapped addresses. Your local environment is probably an earlier 3.12.x that still emits the hexadecimal tail. Either way, I agree the test should assert semantic equivalence instead of the string form.

[bsmith5uoe]

Thanks for the hint - my local environment is Ubuntu Noble 24.04 LTS: it's at patch-level 3.12.3-1ubuntu0.8 - considerably behind the latest 3.12. I should probably open a Ubuntu bug as dealing with inconsistently presented IPv4-mapped addresses is awkward.