Bug report

Bug description:

IPv6Interface.is_unspecified is False for the IPv4-mapped address ::ffff:0.0.0.0, even though the interface's own .ip and .network both say True. gh-122792 made IPv6Address.is_unspecified follow the mapped IPv4 address, but the IPv6Interface override still compares the raw integer with 0 instead of deferring to super() the way is_loopback does since gh-117566.

>>> import ipaddress
>>> i = ipaddress.ip_interface('::ffff:0.0.0.0')
>>> i.is_unspecified, i.ip.is_unspecified, i.network.is_unspecified
(False, True, True)
>>> ipaddress.ip_interface('0.0.0.0').is_unspecified
True

Expected True, matching ip_address('::ffff:0.0.0.0').is_unspecified and ip_interface('0.0.0.0').is_unspecified.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-161100: Fix IPv6Interface.is_unspecified for IPv4-mapped addresses #161101
• [3.15] gh-161100: Fix IPv6Interface.is_unspecified for IPv4-mapped addresses (GH-161101) #161136