https://github.com/python/cpython/commit/c7bbf040e721781be8f11a3b0716220835d4de2f commit: c7bbf040e721781be8f11a3b0716220835d4de2f branch: main author: Serhiy Storchaka <[email protected]> committer: serhiy-storchaka <[email protected]> date: 2026-07-20T19:59:56Z summary:
gh-154291: Fix socket.has_dualstack_ipv6() on DragonFly BSD (GH-154292) On DragonFly BSD setsockopt(IPPROTO_IPV6, IPV6_V6ONLY, 0) succeeds without actually clearing the flag, so has_dualstack_ipv6() wrongly returned True. Verify with getsockopt() that IPV6_V6ONLY was cleared. Co-authored-by: Claude Opus 4.8 (1M context) <[email protected]> files: A Misc/NEWS.d/next/Library/2026-07-20-22-03-44.gh-issue-154291.Mi5HeQ.rst M Lib/socket.py diff --git a/Lib/socket.py b/Lib/socket.py index 03c3fe88f15cfe..2a4f875f76b069 100644 --- a/Lib/socket.py +++ b/Lib/socket.py @@ -900,7 +900,9 @@ def has_dualstack_ipv6(): try: with socket(AF_INET6, SOCK_STREAM) as sock: sock.setsockopt(IPPROTO_IPV6, IPV6_V6ONLY, 0) - return True + # On some platforms (e.g. DragonFly BSD) setting IPV6_V6ONLY to 0 + # silently has no effect, so check that it was actually cleared. + return sock.getsockopt(IPPROTO_IPV6, IPV6_V6ONLY) == 0 except error: return False diff --git a/Misc/NEWS.d/next/Library/2026-07-20-22-03-44.gh-issue-154291.Mi5HeQ.rst b/Misc/NEWS.d/next/Library/2026-07-20-22-03-44.gh-issue-154291.Mi5HeQ.rst new file mode 100644 index 00000000000000..d962f8987ad491 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2026-07-20-22-03-44.gh-issue-154291.Mi5HeQ.rst @@ -0,0 +1,3 @@ +Fix :func:`socket.has_dualstack_ipv6` to return ``False`` on platforms such as +DragonFly BSD where setting ``IPV6_V6ONLY`` to 0 silently has no +effect. _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
